CHAPTER IV.

RESULTS IN PROOF OF THE TENABLENESS OF THE PROPOSITION.

SECTION I.

OBSERVATIONS ON SOME OF THE LAWS OF EPIDEMIC DISEASES.

The results obtained by comparing certain facts connected with Epidemic Affections of animals, with analogous affections in plants, afford, from the few instances I shall here notice, a very strong presumption, that analogous causes operate in the production of these affections. I have already quoted from Hecker, to shew that previously to, and during the Epidemics of the Middle Ages, the minuter forms of animal and vegetable life appeared to be called into existence, much more abundantly than usual; that famines prevailed in consequence of failure of cereal crops, no doubt depending then, as now, upon the various forms of fungiferous growth. I cannot refrain quoting here, a passage or two from our old friend Virgil; for he confirms not only the fact of peculiar showers in {156} connexion with diseases, but he also refers to the rust of corn, thus:

150. "Mox et frumentis labor additus; ut mala culmos Esset rubigo ... ... Intereunt segetes."

_Georg. 1._

Then:

311. "Quid tempestates autumni et sidera dicam?

. . . . . .

322. "Saepe etiam[61] immensum coelo venit agmen aquarum Et foedam glomerant tempestatem imbribus atris Collectae ex alto nubes."

_Georg. 1._

The occurrence of black showers in this country has been observed during the present year, and I understand that in the fenny countries of the East, the corn has suffered much from the Uredo. I am not mentioning the circumstances as cause and effect, but merely to call attention to the fact, that unusual phenomena of this kind have been generally associated with disease of the animal and vegetable tribes.

The same causes also predispose plants as well as animals, to epidemic attacks of disease. The repeated observations in the public journals on the subject of ventilation, drainage, and over-crowding, render all notice from me needless, to shew that these, though they do not produce the diseases {157} treated of, yet that under the influence of bad air, bad drainage, and over-crowding, epidemics are fostered and spread.

Lastly, says the Count Philippo R['e], "I would remark that if _bad cultivation, and especially bad drainage, does not produce bunt or smut, it is certain that those fields, the worst treated in these respects, suffer the most from these diseases_."

It has been remarked by many observers, that a greater fecundity has attended upon Pestilences, and this has been proved by comparison, that the births in proportion have far exceeded the ordinary limit.[62] In juxtaposition with this observation, I will place the following, not as a proof, but as a remark made quite independently of the subject of which I am treating. "From the first the diseased ears are larger than the healthy ones, and are sooner matured. What appears singular, but which I have not, perhaps, sufficiently verified, is _that the seeds are more abundant than in a sound ear_."

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Now these are facts which require amplification, and if these two alone should be shewn upon an extensive field of observation, to apply not only to corn, but to other members of the vegetable kingdom, as I doubt not will be the case, though I am not fully prepared to prove it, it would be difficult to dissociate the fertility of the two living kingdoms from the operations of one and the same, or an analogous law.

The epidemic diseases of plants are both infectious and contagious, at times they are observed to be endemic only, and then depending particularly upon some local causes. This is a law of diseases which applies equally to those of men and animals. In connexion with this law is another, which, as far as I am aware, has not hitherto been noticed in connexion with plants. The potato disease, which excited so much interest and created so much anxiety for the poorer classes of society, led the Government of this country to employ the most learned men to investigate the subject, in the hope of propounding some reasons which should explain the cause of the calamity, and thereby deduce a method of eradicating the evil, or, in other words, discover a cure for the disease. Many were the opinions as to the cause of the distemper, which it were useless here to recount, but a method was suggested, to which most people, I believe, looked forward with great anticipations, and this was to obtain native seed, and to sow it on virgin soil. Was the end accomplished? No. {159} For though the seed was sown, and the plants grew, the disease still appeared among the newly imported individuals, to as great an extent, as among the native or domesticated plants.

As a parallel to this, it may be stated, that, as regards either endemic or epidemic disease, those persons newly arrived, either in a district or country where these prevail, are even more liable to them than the residents.[63] Again, I have learned, that where the potato disease has been so bad as to render the crop almost valueless, the best plan to be adopted is, to allow the plants to remain in the earth, and thus leave such as retain their germinating powers to come up spontaneously the following year. I certainly saw one large field treated in this way, yield a crop almost without disease.

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The seasoning, in this instance, seems to bear a comparison with the seasoning of animals and man, under a variety of diseases, which for a time renders them insusceptible of another attack. It therefore does not appear so improbable, that these affections may be regarded, as Unger, the German botanist supposed, the Exanthemata, or Eruptive Fevers of vegetables.

Another feature seems to associate the Epidemics of plants and animals, in a manner suggestive of analogous causes operating in both instances.

The lungs of animals and the leaves of vegetables, are their respiratory organs, by means of which, the blood in the one case and the sap in the other, derive gas from the air, and impart gas to it, each taking what is thrown off by the other.

Now the epidemics among vegetables, have a remarkable tendency to exhibit their effects primarily on the leaves, and particularly on those parts which are appropriated to the function of respiration. It is from the stomates that many of the fungi commence to germinate, and their fructification may be seen sprouting from the opening composed of a chink, surrounded by a peculiar arrangement of cells, which constitute the breathing apparatus of their victim.

In the earlier epidemics, of which we read, one of the most remarkable circumstances, was the extraordinary influence the poisonous matter appeared to {161} exercise over the lungs,[64] and they again, were the means of propagating the disease, and spreading the contagious particles through the atmosphere, for we read: "Thus did the plague rage in Avignon for six or eight weeks, and the pestilential breath of the sick, who expectorated blood, caused a terrible contagion far and near, for even the vicinity of those who had fallen ill of plague was certain death; so that parents abandoned their infected children, and all the ties of kindred were dissolved."[65] "The like was seen in Egypt. Here also inflammation of the lungs was predominant." "Here too the _breath_ of the sick spread a deadly contagion."

It is more than probable that all infectious matter obtains an entrance to the system through the lungs. Inspiring the air containing the pestilential semina is, indeed, the only plausible explanation of infection; for though the skin is indubitably an absorbing {162} surface, and capable of taking up and conveying to the blood any noxious matter applied to it, yet it is far more probable that the lungs would effect this process with greater rapidity. Then the stomach, the only other absorbing surface to which extraneous matter can be applied, is not likely to be the part where the elements of disease would obtain an entrance to the system, for many facts prove, that infectious matter may be swallowed without any injurious consequences, unless in a very concentrated state. Instances are not easily found of diseased matter having been swallowed, except where diseased vegetables have formed under some combination of circumstances, a portion of diet.[66]

Many facts are on record which prove the powerful effect of diseased grain when made into bread, and taken for any length time as a principal article of food. The history of Ergot of Rye is too fresh in the memory of most people to require more than an allusion here. The stomach had no power over the secale, its poisonous properties were retained, after having been submitted to the digestive process, as was evidenced by the abortions and gangrenes it occasioned.

But diseased wheat is also capable of inducing {163} gangrene, and it is more than probable, that many diseases might be traced to the use of infected grain of various kinds. An interesting account of a family who lived at Wattisham, near Stowmarket, in Suffolk, and all of whom suffered more or less from living on bread made of smutty wheat, may be found in the Philosophical Transactions. The mother of this family and five of the children, consisting of three girls and two boys, all suffered from gangrene of the extremities; the father lost the nails from his hands, and had ulceration of two of his fingers.[67] Dr. Woollaston wrote thus in a letter on this case: "The corn with which they made their bread was certainly very bad: it was wheat that had been cut in a rainy season, and had lain on the ground till many of the grains were black and totally decayed, but many other poor families in the same village made use of the same corn without receiving any injury from it. One man lost the use of his arm for some time, and still imagines himself that he was afflicted with the same disorder as Downing's family." It is not unlikely this was the case, for numbness and loss of power was one of the well marked characters of the disease.

What other afflictions may be due to diseased vegetation and adulterated articles of food, and what loss of life may accrue from cheap and adulterated {164} drugs and chemicals is hardly yet dreamt of.[68] The systematic practice of adulteration of almost every article of diet which comes to table has become a serious question for the legislature to consider. Take only the article of milk, upon which the young children of large towns and cities, make their chief meals, with the addition of bread. How much milk comes into London from the country, how much is obtained from stall and grain-fed cows in the metropolis, and how much is said to be consumed, would be an interesting calculation. It is pretty well known that a mixture is sold by which a retailer of milk may increase his supply by one-third or one-half. It was discovered in Paris that the brains of animals, when prepared in a particular manner, formed, when mixed with a certain proportion of milk and water, a very fine and deceptive cream; in that city this system was carried on to a considerable extent. I could not help alluding to these facts while speaking of diseased grain, for who shall say to what extent a miller in a large way of business, may be able to "work in," as it is called, a considerable amount of smutty corn in the manufacture of flour? Now, as diseased grain is known {165} to induce abortion, it is impossible to tell how small a portion may in some cases produce the effect; we may therefore say with Thomas of Malmesbury, "There is no action of man in this life which is not the beginning of so long a chain of consequences, as that no human providence is high enough to give us a prospect to the end."[69]

To return,--associated with these observations are other facts of considerable weight. Before and during pestilences, abortions are more frequent than in ordinary times; infectious and contagious diseases induce abortion; besides this, and independently of disease, conditions of the atmosphere have been known to exist when abortion has been an epidemic affection; of this Dr. Copland says, "to certain states of the atmosphere only can be attributed those frequent abortions sometimes observed which have even assumed an epidemic form, and of which Hippocrates, Fischer, Tessier, Desormeaux, and others have made mention." With this reference I will close the subject of comparison between the affections of the breathing apparatus in animals and plants, merely alluding to the probability that under some conditions of atmosphere, independently of heat, &c. vegetables without any other assignable cause will become abortive.

* * * * *

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SECTION II.

WHAT IS THE NATURE OF THOSE POISONS WHICH MOST RESEMBLE THE MORBID POISONS IN THEIR EFFECTS ON THE BODY?

In the early part of this book, I considered the nature of poisons generally, and had occasion to remark upon the characters which separated poisons into two distinct classes. 1st, Those which have the power of self multiplication; and 2nd, Those destitute of this property.

Of the first we have seen that the poisons of epidemic diseases multiply both in and out of the body.

The poisons of infectious diseases, not usually epidemic, do the same. Those of endemic affections, such as ague and some fevers, usually become multiplied out of the body only, but under some circumstances, and peculiar atmospheric conditions, they may be also multiplied within the body. The amount of these poisons necessary to produce their specific effects, may be inappreciable. Of the second class, there are two kinds, those derived from the organic kingdom and those derived from the inorganic kingdom. Of these, the amount necessary to produce their specific effects is appreciable and pretty well known.

But among those poisons, consisting of organic {167} products, there is one which seems to hold an intermediate place. This is derived from one of the Fungals, and as it takes this remarkable position as a link of connexion between the two classes of poisons, I may be excused quoting a passage of some length upon this agent, from Dr. Lindley's Vegetable Kingdom. "One of the most poisonous of our fungi, is the Amanita muscaria, so called from its power of killing flies, when steeped in milk. Even this is eaten in Kamchatka, with no other than intoxicating effects, according to the following account by Langsdorf, as translated by Greville. This variety of Amanita muscaria, is used by the inhabitants of the north-eastern parts of Asia in the same manner as wine, brandy, arrack, opium, &c. is by other nations."--"The most singular effect of the amanita is the influence it possesses over the urine. It is said, that from time immemorial, the inhabitants have known that the fungus imparts an intoxicating quality to that secretion, which _continues for a considerable time after taking it_. For instance, a man moderately intoxicated to-day, will by the next morning have slept himself sober, but (as is the custom) by taking a teacup of his urine, he will be _more powerfully intoxicated_ than he was the preceding day. It is, therefore, not uncommon for confirmed drunkards to preserve their urine, as a precious liquor against a scarcity of the fungus. The intoxicating property of the urine _is capable of_ {168} _being propagated_; for every one who partakes of it has his urine similarly affected. Thus with a very few amanitae, a party of drunkards may keep up their debauch for a week."

This property of the amanita, at once places it in a separate category from all other organic poisons, it has yet to be shewn upon what this intoxicating fungus depends for its activity. Whether some secretion is formed in the tissue of the plant, or whether some new arrangement of the particles of matter or modification of the sporules, is brought about by entering the system, it is impossible to say. Langsdorf states that the small deep-coloured specimens of amanita, and thickly covered with warts, are said to be more powerful than those of a larger size and paler colour. As the effect is not produced until from one to two hours after swallowing the bolus, and as a pleasant intoxication may be obtained by this agent for a whole day, and from one dose only, there is a defined line between this and the ordinary narcotics and stimulants in common use. That the digestive powers of the stomach have no influence over the intoxicating properties of the plant, is manifested in the fact, that the active principle passes into the urine, not only not deteriorated but apparently increased, for, as we have seen, a teacup of the urine from a man, intoxicated by taking the amanita into his stomach, will cause him to be more powerfully intoxicated than by the {169} original dose. We have, therefore, but two conjectures left for consideration, either the original intoxicating principle is excreted from the system in a condensed form, in which case its indestructibility by digestion, makes it approach the ordinary organic poisons, or there must be an increase of the toxic agent, in which case we must suppose a reproductive process having taken place in the system. "There is," says Dr. Mitchell, "in the wild regions of our western country, a disease called the _milk sickness_, the _trembles_, the _tires_, the _slows_, the _stiff-joints_, the _puking fever_, _&c._" The animals affected with this disease, "stray irregularly, apparently without motive;" they lose their power of attention, and finally tremble, stagger, and die. "When other animals--men, dogs, cats, poultry, crows, buzzards, and hogs, drink the milk or eat the flesh of a diseased cow, they suffer in a somewhat similar manner." This disease is attributed by Dr. Mitchell to the animals having grazed on pasture contaminated with mildew, and the resemblance to the effects of the amanita, together with the persistence of the specific principle within the fluids and tissues of the body, render it more than probable that to some fungoid growth, is due the peculiar toxic effects here noticed. Further: "The animals made sick by the beef of the first one, have been in their turn the cause of a like affection in others; so that three or four have thus fallen victims successively." De Graaf states, that butter {170} made from the milk of diseased cows, though heated until it caught fire, did not lose its deleterious properties. The urine of diseased animals, collected and reduced by evaporation, produced the characteristic symptoms. All these facts point to some peculiarity in the properties of matter not yet investigated or at least not explained. If we may assume that reproduction is here an element of the persistence and apparent multiplication of active matter, I know only of one instance to compare with it. A gentleman about to deliver a lecture on the properties of arsenic, and its history generally, made two solutions of a given quantity of arsenious acid, in the following manner. He took a certain amount of distilled water, and the same of filtered Thames water, and made his solutions of arsenic by separate boilings, he then as soon as possible placed the liquids in identical bottles, carefully prepared for their reception. In the one which contained the arsenic boiled in river water, the hygrocrocis is now growing, while that boiled in distilled water remains perfectly limpid and free from any vegetable production. There can scarcely be a doubt, that the filtration of river water was not sufficiently purifying to remove the minute spores of some lower forms of vegetation, which not only live in arsenic but have resisted the temperature employed in boiling an arsenical solution to saturation.

As to the first class, or truly reproductive and {171} morbid poisons, the most heterogenous ideas have from all time existed. I have introduced the notice of the above poisons, viz. the Amanita, and that which engenders the milk sickness, to compare the results of the morbid poisons on the human body with them, and also to associate them with the effects of diseased grain. From the Amanita and that other fungoid matter which is said to produce the milk sickness, there appears to be a purely toxic action on the system, but in the instance of diseased grain, a blood disease, ending in gangrene, or a specific and peculiar action of the generative organs is the consequence, and where the latter occurs, the poison usually expends itself on these parts, either by inducing abortion, or augmenting the catamenial secretion.

Now, the morbid poisons, if studied only in their results, shew that there is a combination of these two actions. There is usually, in the first place, a toxic or poisonous action, and secondly, a deteriorating or decomposing action on the blood, by which there is a tendency to low or asthenic inflammation and gangrene. It matters not what form of fever we take as an illustration, whether intermittent, pestilential, or exanthematous, either will serve the purpose of shewing how completely the effects of vegetable organic poisons resemble those which for the sake of distinction (I suppose) have been denominated Morbid Poisons.

Take an attack from the paludal poison. It is {172} usually ushered in with head-ache, weariness, pains in the limbs, and thirst, with other symptoms; all these are indicative of a poisonous agent in the blood: then come the full phenomena of the disease at a longer or shorter interval, and tending ultimately to destroy some organ of the body. The mind suffers during the course of the attack, and delirium occasionally happens. In severe cases of this disease, which were more frequent formerly than now, coma, delirium, and frenzy were observed at the commencement of the attack, and a tendency to rapid disorganization of one or several of the viscera.

If we take the effects of poison of Erysipelas, of Scarlet Fever, or Plague, in each we find at the onset more or less general derangement of the system, usually with cerebral disturbance and disordered action of all the dynamic forces of the body, which clearly indicate the action of a poison; then, unless some favourable symptoms arise, the blood exhibits a steady advance towards disorganization, and sphacelation of one or more tissues or parts of the body ensues. In Erysipelas the force of the diseased action is expended on the skin, and subcutaneous cellular tissue; in Scarlet Fever the fauces ulcerate, and slough and the parotids suppurate; in the Plague there is a general tendency to putrefaction, and the formation of glandular abscesses with sphacelas. Without going any further into this matter, for my present intention is merely to draw {173} notice to certain facts, let me now ask, whether or not, do the poisons of the Ergot, the Uredo, and the Amanita, exhibit more analogy in their action on the nervous system, the blood and the tissues, than any other poisonous agents with which we are acquainted? If the whole range of the lower fungi could be examined in reference to their operation on the blood, as decomposers of organic compounds,--if experiments could be made, by which the properties of fungoid matter could be detected, I would venture to say the whole of the phenomena of these diseases could be readily comprehended and their intricacies unravelled.

We know that the fungi are poisonous, that at times and seasons, and under variations of climate, they vary in their effects, and perhaps lose altogether these properties. We know that the fungi produce gangrene of the tissues, and disorganization of the blood; we know that their spores pervade the atmosphere, and are ready, under favouring conditions, to increase and multiply; we know that they are ubiquitous, and that those conditions most favourable to their development, are exactly such as are proved to foster and engender disease, and above all, they have been proved to be the elements of some diseases in man, in animals, and in plants. Can as much be said of any other known agents, animate or inanimate, comprised in our category?

It has been said, we do not see after death,--the {174} interlacing mycilium, or the sprouting pileus; therefore the fungi are not the agents of disease--it has been said that carbonic acid and alcohol are not found as products of diseased action--consequently disease is not a fermentative process. "In all cases," says Liebig, "where the strictest investigation has failed to demonstrate the presence of organic beings in the contagion of a miasm, or contagious disease, the hypothesis that such beings have cooperated, or do cooperate in the morbid process, must be rejected as totally void of foundation and support." Much as I admire the genius of this great man, it is difficult to refrain from remarking, that I doubt if any of his great discoveries would have been made, if, in the first instance, hypotheses had not formed the basis of all his researches. It has been said, "that casual conjunctions in chemistry, gave us most of our valuable discoveries:" and it is from casual conjunctions that hypotheses are usually formed, the working out proves either their fallacy or their truth, but to say that an hypothesis has no foundation, until demonstrated to be true, is rather knocking down argument. And who, let me ask, has been more prolific of hypotheses than our continental neighbour? Yet he, according to his mode of reasoning, would sweep away all such words from the vocabularies of philosophers. What foundation has the chemical hypothesis of disease, when it fails to explain the most important element {175} of contagious and infectious diseases: viz. the reproductive property of their germs?

It is perhaps necessary to say something in explanation of the sudden deaths arising from morbid poisons. They may occur from two causes. One being the result of a concentrated amount of poison germs being inhaled into the lungs, and acting as an ordinary toxic agent; and the other, which I put only hypothetically, the consequence of the rapid evolution of gas in the vessels arising from a sudden decomposition of blood, as it passes through the lungs. The only authority I have for this supposition, is the fact that the blood after death, from pestilential affections, is found to be far advanced towards decomposition; that in Paris last year, two patients were bled while suffering from Cholera, and with the small quantity of blood which flowed, bubbles of air also escaped:[70] and besides this, it was demonstrated by Mr. Herapath, that ammonia was given off from Cholera patients, both by the lungs and skin. These facts, though they are not conclusive, nevertheless render it probable that such an explanation is not entirely out of reason--especially too, when we know how fatal are the effects of uncombined air, when it enters the vessels near to the heart.

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SECTION III.

WHAT RESULTS DO WE OBTAIN FROM THE EFFECTS OF REMEDIAL AGENTS, IN PROOF OF THE HYPOTHESIS?

I have here used the word hypothesis, because, having so far advanced in the enquiry, I trust sufficient has been said to render the term applicable.

Under the term remedial agents, I shall include all those causes, whether natural or artificial, which tend to neutralize or destroy the germs of infection, or miasmatic poison, whether this be effected out of or within the body.

First, then, let us consider the results of drainage and cultivation in removing the causes of endemic disease. One well authenticated case is as good as a thousand. I will take one, which, from its source, will be received as unexceptionable; and from its association with a very learned and amusing book, will be accepted as an agreeable reminder of the many pleasant hours spent in the perusal of the poet Southey's "Doctor."

"Doncaster is built upon a peninsula, or ridge of land, about a mile across, having a gentle slope from east to west, and bounded on the west by the river; this ridge is composed of three strata; to wit, of the alluvial soil deposited by the river in former {177} ages, and of limestone on the north and west; and of sandstone to the south and east. To the south of this neck of land, lies a tract called Potteric Carr, which is much below the level of the river, and was a morass, or range of fens when our Doctor first took up his abode in Doncaster. This tract extends about four miles in length, and nearly three in breadth, and the security which it afforded against an attack on that side, while the river protected the peninsula by its semicircular bend on the other, was evidently one reason why the Romans fixed upon the site of Doncaster for a station. In Brockett's Glossary of North Country words, Carr is interpreted to mean 'flat marshy land,' 'a pool or lake;' but the etymology of the word is yet to be discovered.

"These fens were drained and enclosed pursuant to an Act of Parliament, which was obtained for that purpose in the year 1766. Three principal drains were then cut, fourteen feet wide, and about four miles long, into which the water was conducted from every part of the Carr southward, to the little river Torne, at Rossington Bridge, whence it flows into the Trent. Before these drainings, the ground was liable to frequent inundations; and about the centre there was a decoy for wild ducks; there is still a deep water there of considerable extent, in which very large pike and eels are found. The soil, which was so boggy at first that horses were lost in attempting to drink at the drains, has been brought {178} into good cultivation, (as all such ground may be) to the great improvement of the district; for till this improvement was effected, _intermittent fevers and sore throats were prevalent there, and they have ceased from the time the land was drained_. The most unhealthy season now, is the spring, when cold winds, from the north and north-east, usually prevail during some six weeks; at other times Doncaster is considered to be a healthy place. It has been observed that when endemic(?) diseases arrive there, they uniformly come from the south; and that the state of the weather may be foretold from a knowledge of what it has been at a given time in London, making an allowance of about three days, for the chance of winds. Here, as in all places which lie upon a great and frequented road, the transmission of disease has been greatly facilitated by the increase of travelling."

I feel certain of being excused for transcribing this long passage from Southey. It would have been impossible to convey its whole meaning without giving it entire. The continuation of the chapter is no less instructive and applicable to our subject, though more particularly so to an extension of the enquiry. The sore throats and intermittents, from which Doncaster has been freed, by the drainage of Potteric Carr, informs us at once that decomposing matter is the material by which the poison of fever is vivified and sustained, the wet and boggy state of the soil is just the condition, when no drainage exists, to bring into activity the germs of {179} disease, which otherwise would lie latent. So satisfied and acquainted are we with the elements necessary for the production of fever, that we might as certainly bring about an endemic intermittent by forming an artificial bog, as we could be sure of growing mushrooms by making a bed in the manner laid down by gardeners for this purpose. Dr. Lindley also says, "the _Polyporus fomentarius_ has been artificially produced in Germany, but merely by placing wood in a favourable situation, and keeping it well moistened. Five or six crops were obtained in the year."

Let warmth, moisture, darkness, and decaying matter be given, and inanimate disintegrated particles will soon be converted into definite forms and combinations instinct with life. It is by the unseen forms of living beings, that the atmosphere is preserved from becoming charged with deadly gases; they take the first rank in the great scheme of animated beings, the plant first, and then the animal. "Let the earth bring forth grass." "Let there be lights in the firmament." "Let the waters bring forth the moving creature, and fowl that may fly," and "Let the earth bring forth the cattle, the creeping thing, and the beast." This is the order of creation, of living things, and the earth was prepared by vegetation for the animal world. The work of conversion is accomplished by vegetation; and this is consumed for the construction of higher organizations.

The laws which govern and control the universe, {180} are as definite and as wonderful among invisible atoms, as those which regulate the enormous masses floating in space; and the time will come when the advancing intellect of man will measure and weigh the morbid poisons, as he measures and weighs the stars. Why should the laws of Epidemics be less understood, than the laws which govern the course of comets? The aspirations of man have led him to penetrate the heavens, which charm and inspire him; he studies rather the more violent disturbing elements of nature, the thunder-cloud and the fire of heaven, than the silent pestilence which steals over the earth. I cannot conceive it possible that the Intellects, which are occupied in procuring means for the Majesty of this empire to issue her mandates with the velocity of a spirit to the nethermost parts of the earth, should be incapable of solving so deeply interesting a mystery as the causes and nature of pestilential diseases. It would seem that man prefers to issue a mandate of destruction many thousand miles distant, than to disarm the pestilence at his door. It is barely a century since Galvani observed the twitchings in the muscles of a frog's leg, and the battery, still named after him, has already become an agent of instantaneous communication between places many miles distant. But how many centuries have passed away, each one succeeding the other, with its millions of victims to epidemics? And where are the remedies for the evils? Drainage and cleanliness, with all their advantages, were better understood and more fully carried out by the ancient {181} Romans than by ourselves; there are monuments, though crumbling to decay, to tell us of the vast enterprise of these people and of the value they set upon a healthy and vigorous constitution, and how well they understood the means of warding of disease.

Cultivation and drainage are now fully understood to be the basis by which a healthy condition of air is to be obtained, next to that, cleanliness and ventilation; if either be neglected a sickly, mouldy, and unwholesome contamination of atmosphere ensues; the odour of a bog is proverbially mouldy, and so is that of an ill-ventilated house or cellar; dryness, or the fresh pleasant scent of clean water, are the antagonists of these; the aromatic odours of vegetation are opponents of putrefaction, and consequently of the development of the lower forms of life. All empyreumatic matters prevent mouldiness and decomposition; and odours arrest and prevent the growth of mouldiness. The oil of birch, with which the Russia leather is impregnated, and which gives it so pleasant an odour, effectually prevents mouldiness, and consequently decay.

Lindley says, "It is a most remarkable circumstance, and one which _deserves particular enquiry_, that the growth of the _minute fungi_, which constitute what is called mouldiness, is _effectually prevented_ by any kind of perfume."[71] Cedar has {182} been used, from time immemorial, for a like purpose; and I doubt not the recommendation of Virgil, before quoted, in reference to the burning of cedar, was founded on some practical utility of this kind, though its _modus operandi_ was unknown to him. Allied to these is a curious circumstance, and worthy attention. I copy the following from an old work on Pestilences. "It is remarkable that when the Plague raged in London, Bucklersbury, which stood in the very heart of the city, was free from that distemper; the reason given for it is, that it was chiefly inhabited by druggists and apothecaries, the scent of whose drugs kept away the infection, which were so unnatural to the pestilential insects, that they were killed or driven away by the strong smell of some sorts of them." "The smell of _rue_, and the smoke of tobacco, were prescribed as remedies against the infection; but especially tar and pitch barrels, which it was imagined preserved Limehouse, and some of the dock-yards from infection."[72]

Pitch and tar dealers are everywhere spoken of as being remarkably exempt from infectious diseases.

Cold infusion of tar was used in our colonies as a prophylactic against the Small Pox. Bishop {183} Berkeley was induced to try it when this disease raged in his neighbourhood. The trial fully answered expectation--for all those who took tar-water, either escaped the disease, or had it very slightly.

Tan yards and places in the immediate vicinity, are said to be free from pestilences. The tanners of Bermondsey are said to have escaped the Plague of London, and one person only died in Gutter Lane, where was a tan yard. The tanners of Rome are also stated to have been free from Plague. Dr. McLean refers to the exemption of tanners at Cairo. _Tannin is prejudicial to most vegetables_,--but Dr. Lindley says it is not always so to fungi. "A species of Rhizomorpha is often developed in tan pits." I should imagine that neither plants nor insects would be found very abundantly, where tannin prevails; yet we find that the gall-nut is formed for the protection of an insect from injury by weather, and as a temporary means of sustenance.

The custom of fumigating with odoriferous substances, does not therefore appear upon this view of the matter to be destitute of importance; indeed, the universal practice stamps it at once, as an efficacious remedy for the purposes of disinfection. The introduction of chlorine fumigation, seems to have superseded, in a great measure, the use of fragrant herbs and woods; and it is questionable whether the substitution be altogether desirable or {184} advantageous. Many scents may be agreeably and usefully employed, with much less chance of annoyance to the patient, and considerably less injury to articles of furniture, &c.

The fumigations of sulphurous acid and chlorine are, perhaps, more adapted as disinfectants in uninhabited apartments;--their power to destroy vegetation, is well known. They have been used, chiefly, with the idea of neutralizing gaseous exhalations, particularly chlorine, as it tends to combine with hydrogen, to form hydrochloric acid, and then to unite with ammoniacal matters, forming hydrochlorate of ammonia. This, supposing noxious or pestilential effluvia consisted of the ammoniacal exudations variously combined, was an exceedingly efficacious method of rendering them inert; but as we feel convinced that no ammoniacal compound could possibly be the cause of infection, we must look to the influence these gases possess over other forms of matter, and as they are so destructive, even in minute quantities, to vegetable existence, it is possible that their beneficial effects may be due to this property. The immediate neighbourhood of gas works is prejudicial to vegetation, I imagine, from the amount of sulphurous vapours, and to this has been attributed the exemption of persons employed in these works. Many other instances might be cited of a similar nature.

I have now to speak of medicinal agents, and here comes a considerable difficulty. {185}

If we might believe all that has been written on the sure and certain remedies for the "ills that man is heir to," we should be led to acknowledge that both nature and art were prodigal in antidotes and specifics. The all-bountiful hand of nature, I do not doubt, has at the same time scattered the seeds of good and of evil. The fertilizing showers fall to irrigate the soil, and produce food and nourishment to man; here and there is the reeking morass "feeding unnatural vegetation," and if man takes up his abode in its vicinity, the rains which made it unhealthy, have also made it highly fertile; by labour and cultivation he may convert the mephitic bog into a waving corn-field, and the seeds of life and sustenance be made to supplant the seeds of death and corruption.

It is generally believed, that where there are particular and specific diseases, there also may be found appropriate and specific remedies; the discoveries of chemistry, it is not improbable, may in some respects have retarded the progress of natural medicine. In the early ages of the world, the "healing plant" must have formed the staple of medical commerce, for though Tubal Cain[73] has been considered as the first surgical instrument maker, because he was the first artificer in brass and iron, we have not discovered that chemical compounds entered into the composition of physic, till very {186} many years after his time. To the alchemists we owe the science of chemistry, and much of the physic of the present day may be traced to them. The multiplicity of ingredients which at one time entered into the composition of one dose of physic could only be spoken of under the title of "legion." Who shall specify the active and curative ingredient (if there be one), when from five to a hundred may have been exhibited at the same time? It has been the pride of our physicians, that the pharmacopoeia has been simplified; it has not reached its most simple form yet. That many simple plants have specific and wonderful power over disease, is an indubitable fact, but I firmly believe that the laudable, though mistaken efforts of physicians to improve their effect by various combinations, have been the means of throwing many valuable medicines into oblivion; I must also add, that cheap physic and adulterations have had no small share too in the banishment of much valuable physic from ordinary practice. It has been believed, and I think with much reason, that a thorough search into the qualities of plants, would shew that "they are capable of affording not only great relief, but also effectual and specific remedies." "That they are not already found, is rather an argument that we have not been sufficiently inquisitive, than that there are no such plants endued with these virtues."

Of the result obtained by medical treatment, in cases of epidemic or infectious disease, it is most {187} difficult to speak, but as my province here is only to shew that living germs are the morbific agents, I have but to refer to such remedies as have been most extolled in controlling these affections. The disinfectants have already been mentioned in a cursory manner. An enumeration only of simple medicines used during the late Epidemic, shall conclude this work, as the treatment in former times could not by any possibility furnish satisfactory information. Aromatics and fragrant stimulants have in all times taken the foremost rank with acids, such as vinegar, lime and lemon juice. Mr. Guthrie's adoption of lemon juice in preference to bark, which he said made him worse while suffering from an attack of fever, during the Peninsular campaign, and his speedy recovery from the disease, though not from its effects, shews, when many others can bear equal testimony to its value, that such a remedy though simple is not to be despised.

But to the late Epidemic. Dr. Stevens' saline treatment, appears, on the whole, to have been the most successful. Common salt was used both medically and dietetically, and formed the greatest bulk of the medicine employed. Chlorate of potash and carbonate of soda were added to the medicine.

The nitro-hydrochloric acid was used with success at St. Thomas's Hospital.

Dr. Copland used chlorate of potash, bicarb. soda, hydrochloric, ether, and camphor water.

Dr. Ayre's calomel treatment had as many, if {188} not more, opponents than advocates. Phosphorus had several advocates.

Creasote and camphor were lauded by some. The beneficial operation of all these remedies might be explained on the theory here supposed, that living germs are the cause of Epidemic disease, but the specific action of any one remedy has not yet had sufficient attention or trial to enable me to make any deductions of a satisfactory or conclusive nature.

In the uncertainty which generally prevailed as to the best method of treating Cholera patients, I was induced (for reasons stated in a pamphlet published last year) to try the efficacy of sulphur, which had been extolled as a specific. In its effects I was not disappointed; but as the results are already before the public, I need not do more than refer to it among other remedies.

I did not contemplate even alluding to this subject, as it would extend far beyond my intended limits. This portion of the enquiry would be more properly carried out by keeping records of cases, treated in accordance with the view attempted to be established, and I have not the slightest hesitation in saying, that the most ample success would ultimately attend a well directed practice, based upon the principles inculcated in these pages.

* * * * *

{189}

CONCLUSION.

In making the foregoing sketch, I have attempted to put together some ideas on a subject, which has for the last few years been a theme for meditation in leisure hours, viz. What are the causes of Epidemic, Endemic, and Infectious Diseases? The occurrence of Epidemic Cholera last year in this country, awakened a spirit of enquiry. Where there is unrest, whatever may be the cause, there also is disquiet and discontent. When the oracles of the age were consulted in the emergency, the discordant answers perplexed and confused the anxious searcher after truth. In the spring of last year, when the enemy was approaching, unseen and unheard, and the thousands of unconscious victims, who are now lying in their graves, were faithfully trusting and fully relying on the heads of our profession, and the resources of our art, what was the state of our defences, and what the nature or character of our resistance? One considerable body of men would discharge from a little tube of glass, a host of almost invisible globular atoms of sugar, said to be as potent and inscrutably operative as the unseen enemy. These infinitesimal practitioners assured the people that they "_had powerful means of subduing the disease_," {190} but even they differed among themselves, though they carried out to the fullest extent the doctrine of their leader, _similia similibus_, which we may suppose to refer in this case to the minuteness of the opposing armamenta. Without, however, agreeing with this school, I may quote a passage from Dr. Curie, which is, alas! too true: "We have shewn, as they must (allopathists), and many of them do acknowledge, that they have no fixed basis, no natural law upon which their treatment rests."

Who can deny the force of this observation? Sheltered by a principle, it matters not how fallacious, a man is placed as behind a barrier. If with any reason it could be shewn that the infinitesimal doses, could by no possibility effect a cure in Cholera; if it could be demonstrated by any line of argument, that a poison, a living poison, circulates with the blood, or lodges in the tissues, the homaeopathist must fall; his "electricity and mineral magnetism," and "_powerful concentration of life power towards the digestive canal_," will stand for what they are worth. That minute doses of medicine can exert an active influence over the body is not to be denied, but these must consist of powerful drugs, as arnica, aconite, and nux vomica, with others, and it is more than probable, that of such medicines, an inconceivably small amount may produce a specific effect upon some portion of the organic nervous system.

How is it that a dose of nitre or digitalis, "can {191} convert cheerfulness into low spirits," or a grain of red sulphuret of antimony, "excite warmth and lively spirits?"[74]

Why should indigo dyers become melancholy, and scarlet dyers choleric?[75] We do not know. But there is one thing we most certainly do know, that a poison may be disarmed by an antidote, and the amount of the latter must be in proportion to that of the former, and as epidemic and contagious diseases do most unquestionably depend upon poisons of a specific nature, and of great amount and activity, an infinitesimal remedy, however it may claim to direct and control the organic forces, under slight and ordinary disturbances, can be no more effectual in destroying the poison of fever, or small pox, than in neutralizing arsenic or prussic acid.

The uncertainty which generally prevails as to the treatment of Epidemic diseases, Fevers, &c. induced me to put together the notions which are contained in these pages, in the hope of leading to some definite ideas of the causes of these affections, and consequently to a more uniform and scientific mode of treating them.

I have endeavoured to shew that reproduction is a phenomenon inseparable from morbific matter, and that in all probability the vegetable kingdom is the source of the germs.

{192}

The train of argument adopted is such as appeared to me most natural for such an enquiry, and it rests now only with those who are capable of deciding whether such a course, though (I am sensibly aware) not without many faults in conception and execution, is calculated to advance the science of medicine and the interests of mankind.

The real tree of knowledge, possesses in the spongioles of its roots, an elective property, by which truth alone can enter; nourished and sustained by this, it sends a fragrant incense and breathing odour on high, and dispels the mists of ignorance and superstition. In natural causes and reasonable deductions we must seek for instruction and solid information, for in over-straining either nature or art, deformity and error must inevitably be the result.

THE END.

NORMAN AND SKEEN, PRINTERS, MAIDEN LANE, COVENT GARDEN.

* * * * *

NOTES

[1] "It matters little how vague and false hypotheses may appear at first: experiment will gradually reduce and correct them, and all that is required, is industry to elaborate the proof, and impartiality to secure it from distortion."--_Sewell_ "On the Cultivation of the Intellect."

[2] It is stated by Mr. Crosse, of Norwich, that vaccination was adopted in Denmark, and made compulsory in 1800. After the year 1808 Small Pox no longer existed there, and was a thing totally unknown; whereas during the twelve years preceding the introduction of the preventive disease, 5,500 persons died of the Small Pox in Copenhagen alone.--_Dr. Watson's Lectures._

Dr. Blick, an intelligent Danish physician, corroborated the above statement to Dr. Watson himself in the year 1838.

[3] Philosophy of Life, Lecture 6, translated by the Rev. A. J. W. Morrison, M.A.

[4] The following I quote from Dr. Fuller on Small Pox and Measles:--

"To this purpose some (and particularly Kircherus) are of opinion that animalcules have been the causes of malignant and pestilential fevers in epidemic times, which differ in essence and symptoms, according to the nature and venoms of those creatures.

"Thus the atmosphere and air is filled both from above and beneath with innumerable millions of millions of species or corpuscles, aporrhoeas, steams, vapours, fumes, dust, little insects, &c. all which make it such a wonderful chaotic compost of things that contains the _seeds_ of good and evil to man as surpasseth the understanding (as I suppose) of even the highest order of archangels."

[5] I learn from an undoubted authority that the cow when "slack of health" eats with avidity the "field parsley;" the sheep under similar circumstances seeks the ivy, and the goat the plantain.

From an equally good source I have the following: that rabbits and hares, when they are what is commonly called _pot-gutted_, seek the green broom, though at a distance of _twenty miles_.

[6] "My settled opinion is, that in regard every effect is necessarily such as its cause; it must needs be that every sort of venomous fevers is produced by its proper and peculiar species of virus.

"And that the manner and symptoms of every such fever is not so much from the particular constitution of the sick; as from the different nature and genius of their specific venom which caused them.

"And I conceive that venomous febrile matters differ not in degree of intenseness only, but in essence and _toto genere_ also; and that venomous fevers are for the most part contagious."--_Thomas Fuller, M. D. 1730._ "Another important class of organic poisons are those which when introduced in almost inappreciable quantities into the system, seem to increase in quantity; and which when communicated in the same inappreciable quantity from the individual poisoned to one who is healthy, excite the same series of febrile phenomena and local inflammation, and the same increase in the quantity of the poisonous agent."--_Med. Chir. Review._

"This unseen influence working in the body, presents very striking analogies to the modes of operation of different poisons."--_Dr. Ormerod on Continued Fever._

[7] I am aware that the vesicle does not here strictly bear the relation to the original germ, supposing one active particle alone to be sufficient for its production, that the egg does to the bird, for in the former case multitudes of active particles may have been generated from one. I have, therefore, merely used this expression to signify an aggregation of vital forces, such as may be imagined to exist in the bird.

[8] "At an early period the form of the ovisacs is usually elliptical, and their size extremely minute,--their long diameter measuring in the ox no more than 1/562 of an inch, so that a cubic inch would contain nearly two hundred millions of them. They are _at this time_ quite distinct from the _stroma_ of the ovarium; this forms a cavity in which they are loosely embedded."

[9] Coleridge, p. 56.

[10] "All vegetables," says Sharon Turner, "from that pettiness which escapes our natural sight, to that magnitude which we feel to be gigantic, have these properties in common with all animals--organization; an interior power of progressive growth, a principle of life, with many phenomena that resemble irritability, excitability, and susceptibility, and a self-reproductive and multiplying faculty."--_Sharon Turner's Sacred History._

[11] "Plants highly sensitive to light are those of the leguminous, or Pea kind. They always close up in the evening and clasp their two upper surfaces together, presenting only their backs to the air. Plants of pinnated leaves, as the Tansy, are more sensible than these to the effects of light. They fold up when light is too strong, as in Robinia; it produces the same effect as want of light. Its leaves close up, apparently, because they are receiving too much. So they do if a hot iron be brought near them. They contract as if to avoid the heat. Sensitive plants, and those of the Oxalis Lent. are so sensitive that the least motion, even a breath of air, will make them close."--_Sir J. Smith._

"The vitality of plants seems to depend upon the existence of an irritability, which although far inferior to that of animals, is nevertheless of an analogous character."--_Lindley's Introduction to Botany._

[12] Provincial Medical and Surgical Journal. July 10th, 1850. No. xiv. p. 367. "Practical Observations on the Vaccination Question." By E. Oke Spooner, M. R. C. S., Blandford.

"If we examine the Cow Pox and the Small Pox microscopically, as I have done very carefully in every stage, we find that the essential character consists of a number of minute cells, not exceeding the 10,000th part of an inch in diameter, being about one-fourth smaller than the globules of the blood, containing _within their circumference many still more minute nuclei, and presenting_ beyond their circumference bud-like cells of the same size and character as those contained within the circle. They exactly resemble in everything except the size, the globules of the yeast plant, the Torula Cerevesiae. Now if we examine more circumstantially the analogies of what I would call the Torula Variolae with the Torula Cerevesiae, we observe the following corresponding facts.

"What do we accomplish by inoculation as it is called? Simply this. We take on the top of a lancet, or an ivory point, a few of these minute cells or germs, and we put them _in their appropriate nidus_, the subcuticular tissue, where, after a few days if they find their appropriate nutrient elements, they grow and multiply."

Simon, Chemistry of Man, vol. i. p. 127. "Macgregor ascertained that the air expired by persons ill of confluent Small Pox, contained as much as _eight_ per cent of carbonic acid, and in proportion as health was restored the percentage was diminished to its natural standard." Carbonic acid is also produced during the process of fermentation and germination.

[13] See History of the Jews, p. 71.

[14] It is said by Whewell, that the murrain is supposed to have fallen only on the animals which were in the open pasture.--_History of the Jews._

"J. S. Michael Leger, published at Vienna, in 1775, a treatise concerning the mildew as the principal cause of the epidemic disease among cattle. The mildew is that which _burns_ and _dries_ the grass and leaves. It is observed early in the morning, particularly after _thunder-storms_. Its poisonous quality, which does not last above twenty-four hours, never operates but when it is swallowed immediately after its falling."--_Mitchell on Fevers._

[15] "The prevalence of the south-east wind was observed to be particularly favourable to the increase of both cholera and influenza: and I cannot but think that this had some connexion with the general tendency exhibited by the former to spread from east to west. Has the morbific property of this wind aught to do with the haziness of the air when it prevails--a haziness seen in the country remote from smoke, and quite distinct from fog? What is this haze? In the west of England a hazy day in spring is called a _blight_."--_Dr. Williams' Principles of Medicine._

[16] We are to understand also that some peculiar operation took place of a nature difficult to comprehend, which seems also to typify reproduction, for the handfuls of ashes which Moses threw into the air _became a dust in all the land of Egypt_, thus signifying an enormous reproduction of atomic matter.

[17] The Chinese affect to trace the origin of Small Pox back to a period of at least 3000 years, or 20 years beyond the era of the Trojan war, 1212, A. C.

The Chinese pretend to discriminate no less than 40 different species of Small Pox.

"They also pretend to discover whether a person has died by violence or from natural causes, not only after the body has been some time interred and decomposition of the softer parts has commenced, but even after the total disappearance of the soft parts, and when the dry skeleton alone is left."--For the process, see _Hamilton's History of Medicine_, vol. i. p. 31.

To give some notion of the state of Medical Science among the Chinese, I may quote the following: "The theory of the circulation of the blood, Du Halde affirms, was known by the Chinese about 400 years after the deluge; be this assertion veracious or not, no correct knowledge up to the present day, do the nation possess of the circulating system of the human frame."--_China and the Chinese, Henry Charles Sirr, M. A._

According to their anatomy, the trachea extends from the larynx through the lungs to the heart, whilst the oesophagus goes over them to the stomach.

[18] "And Aaron took as Moses commanded, and ran into the midst of the congregation: and behold the plague was begun among the people; and he put on incense and made an atonement for the people. And he stood between the dead and the living, and the plague was stayed."--_Numbers._

The practice of burning scented herbs has been observed in all times during an invasion of the plague, as a means of protection. Also wearing perfumes and aromatic preparations has been recommended. Whether they have any counteracting influence, it is impossible to say.

Virgil in the third Georgic speaks of a murrain among cattle. He says, if any wore a vestment made of wool from an infected sheep, fiery blains and filthy sweat overspread his body, and ere long a pestilential fire preyed upon his infected limbs.

In his directions for preserving the health of flocks he says--

"Disce et odoratam stabulis accendere cedrum."

The motive for burning the fragrant cedar is not mentioned; we cannot doubt but it was a good one, and having some great practical utility, from the following line--

"Galbaneoque agitare graves nidore chelydros."

[19] The earliest mention of this complaint upon which reliance can be placed, is an ancient Arabic MS. preserved in the public library at Leyden. "This year, in fine, the Small Pox and Measles made their first appearance in Arabia." The year alluded to being that of the birth of Mahomet, or the year 572 of the Christian aera.--_Hamilton's History of Medicine_, vol. i. p. 215.

[20] Dr. W. A. Greenhill's translation.

[21] The Black Assize at Oxford, 1572, is an instance in which a pestilential vapour suddenly appeared in the court, "whereby the judge, several noblemen, and more than 300 others, died within three days."

"Of an unaccountable vapour suddenly coming, I have this relation from Richard Humphrey, my neighbour, and a man of veracity, that on Wednesday, April 27, 1727, as he and one Walter, were travelling a-foot from Canterbury; when they came to Rainham, they were assaulted with such a strong loathsome stink, as he thought was like the stench from a corrupted human corpse. They were so offended at it, as thinking it was from carrion in that town, that they would not stay there to rest and refresh themselves, but travelled on for about two hours, mostly in the stench, but sometimes out of it, till they came to the hill that leads down to Chatham: and there they went clear out of it and smelt it no more."--_Dr. Fuller_.

It appears that these persons did not fall sick of any disease, but the fact of itself is remarkable enough.

[22] Hamilton's History of Medicine.

[23] It has been said, that "an induction once carefully drawn, is as perfect from a single instance as it is from ten thousand, and that it is only an uncultivated mind which requires a load and accumulation of knowledge to assist his thoughts."--_Sewell_ "on the Cultivation of the Intellect."

[24] See Dr. Alison's Pamphlet on the Fever in Edinburgh.

[25] Earthquakes have in all times been considered to have some connexion with pestilences. "A most grievous pestilence broke out in Seleucia, which from thence to Parthia, Greece, and Italy, spread itself through a great part of the world, from the opening of an ancient vault in the temple of Apollo, and that it raged with so much fury as to sweep away a third part of the inhabitants of those countries it visited."--_Dr. Quincy, on the Causes of Pestilential Disease._

"Upon an earthquake the earth sends forth noisome vapours which infect the air; so it was observed to be at Hull in Yorkshire, by the Rev. Mr. Banks, of that place, after a small earthquake there in 1703, it was a most sickly time for a considerable while afterwards, and the greatest mortality that had been known for fifteen years."--_Anonymous_, 1769.

[26] See Sharon Turner's Sacred History, text and notes, vol. i. p. 161 & 162.

[27]

"Each seed includes a plant; that plant, again, Has other seeds, which other plants contain, Those other plants have all their seeds; and those More plants, again, successively enclose. Thus ev'ry single berry that we find, Has really in itself whole forests of its kind. Empire and wealth one acorn may dispense, By fleets to sail a thousand ages hence; Each myrtle-seed includes a thousand groves, Where future bards may warble forth their loves."

[28] "On June 5th, 1849, a man and his son, a lad aged 14 years, left Noss to fish, and when five miles out at sea, no vessel being in sight, they both simultaneously became aware of a hot _offensive_ stream of air passing over them. It was so decided, that the crab pots were examined to discover if it were from them, but it did not, and five minutes after the father's attention was directed to the boy, who was vomiting and purging."--_Dr. Roe on the Cholera at Plymouth, Med. Gaz. Aug. 24th, 1850._

[29] Linnaeus remarked that Erigeron Canadense was introduced into gardens near Paris from North America. The seeds had been carried by the wind, and this plant was in the course of a century spread over all France, Italy, Sicily and Belgium.

[30] Hecker.

[31] This is found most generally to be the case where rivers flow through uncultivated tracts of country. The Californian emigrants suffer much from diarrhoea and dysentery, if they drink of the river and certain well waters of that gold district.

[32] "Purification from leprosy. As this fearful disease was contagious and hereditary to the third and fourth generation, the separation of lepers from the camp and congregation, and the destruction of infected houses and clothes, was of the utmost importance to the preservation of public health.

"Leprosy was of three kinds: 1st, Leprosy in man. 2nd, Leprosy in houses. 3rd, Leprosy in clothes.

"Contagious or malignant leprosy was of two kinds, viz.

"1st. The white leprosy, or bright berat, which was the most serious and obstinate form which leprosy assumes. It exhibited itself as a bright white and spreading scale, on an elevated base; turning the hair white in patches, which were continually spreading.

"2nd. The black leprosy, or dusky berat, which was less serious than the foregoing. It did not change the colour of the hair, nor was there any depression in the dusky spot; but the patches were perpetually spreading, as in the white leprosy."--_Analysis and Summary of Old Testament History._ _Oxford._

[33] The Mexican Aloe blows when nine years old, and then dies. At least this is its usual course in the island of Cuba.

[34] "Ground that has not been disturbed for some hundred years, on being ploughed, has frequently surprised the cultivator by the appearance of plants which he never sowed, and often which were then unknown to the country. The principle has been ascertained to be capable of existing in this latent state for above 2000 years, unextinguished, and springing again into active vegetation, as soon as planted in a congenial soil.

"In boring for water near Kingston on Thames, some earth was brought up from a depth of 360 feet, and though carefully covered with a hand-glass to prevent the possibility of other seeds being deposited on it, was yet in a short time covered with vegetation.

"Turner says, from the depth, these seeds must have been of the diluvian age."--_Jesse's Gleanings._

[35] Hamilton's History of Medicine, vol. ii. p. 276, note.

[36] "What I wish you to remark is this, that while almost all men are prone to take the disorder, large portions of the world have remained for centuries entirely exempt from it, until at length it was imported, and that then it infallibly diffused and established itself in those parts."--_Dr. Watson on the Principles and Practice of Physic._

Dr. R. Williams says, "The seeds of intermittent fever lay dormant for months, it was not at all uncommon for cases of intermittent fever to be brought into the hospital eight or ten months after the patients had subjected themselves to the influence of paludal or marsh effluvia."

[37] I have observed in the hot-houses, that many of the exotic plants, which are in company with the diseased vines, have been attacked, while others again have been entirely free.

[38] By causes of the greatest variety plants may become extinct for a time. It is not very easy to trace them, but one fact may be mentioned in proof of the statement. Dr. Prichard states that vast forests are destroyed either for the purpose of tillage or accidentally by conflagrations. "The same trees do not reappear in the same spots, but they have successors, which seem regularly to take their place. Thus the pine forests of North America when burnt, afford room to forests of oak trees."

[39] Hecker says of Chalin de Vinario, that "he asserted boldly and with truth, that _all epidemic diseases might become contagious, and all fevers epidemic_,--which attentive observers of all subsequent ages have confirmed." P. 60.

[40] In 1539, the thirty-first year of Henry the Eighth, was great death of burning agues and flixes; and such a drought that welles and small rivers were dryed up, and many cattle dyed for lacke of water; the salt water flowed above London Bridge.--_Stowe._

In 1556, the fourth of Mary, and the third of Philip, about this time began the burning fevers, quarterne agues, and other strange diseases, whereof died many.--_Stowe._

The next winter, 1557, the quarterne agues continued in like manner, or more vehemently than they had done the last yere.--_Stowe._

[41] Every writer on the climate of Egypt has remarked, that the Endemic Fever which is so frequent, originating on the coast, particularly about Alexandria, becomes occasionally so virulent, that it cannot be distinguished from the _true Plague._--_Robertson on the Atmosphere_, vol. 2. p. 384.

"Endemial Fevers of every situation become occasionally so aggravated, that they cannot be distinguished from such as originate from contagion; and in every unusual virulence of this Endemic Fever, it is probable that it may be propagated afterwards by contagion as every epidemic." _Ibid._ p. 388.

[42] Dr. Ure.

[43] "The metamorphosis of starch into sugar depends simply, as is proved by analysis, on the addition of the elements of water. All the carbon of the starch is found in the sugar; none of its elements have been separated, and except the elements of water, no foreign element has been added to it in this transformation."--_Liebig_, _Organic Chemistry_, p. 71.

[44] As regards starch there appears to be some peculiar faculty regarding it. It is converted into sugar during the ripening of fruit, and it is just possible that being as it is of a cellular nature, the property of vitality may attach to it until it has, by being converted into sugar, fulfilled its destination.

[45] Though I do not consider that the fermentation process is a fac-simile of diseased action, yet I think its phenomena generally afford an apt illustration of the changes which may be effected by living germs. Many able chemists still maintain the entire dependence of fermentation upon the Torula: "M. Blondeau propounds the view that _every kind_ of fermentation is _caused_ by the development of fungi."

The varieties of opinions found in the literature of this subject, forms a curious specimen of scientific enquiry, and is sufficient alone to convince us of its vast importance and extensive relations.

[46] By Dr. Mantell.

[47] Mitchell on Fevers.

[48] We wonder, and ask ourselves: "What does SMALL mean in Nature?"--_Schleiden's Lectures on Botany._

[49] Speaking of the bunt in wheat: "It appears certainly to be contagious, from numerous experiments, which shew that the contagious principle lasts a long time. I have tried it myself; some, however, doubt it, but it cannot be denied, that seed sown, infected with bunt, produces plants similarly affected; every one who has had the slightest experience must be convinced of it."--_Essay on the Diseases of Plants._ _Count R['e]._

[50] We have already spoken of the effects of these poisons, and have stated that the amount of each poison capable of destroying the body is pretty accurately known.

[51] The italics are my own.

[52] Gmelin says: "But the mode of action in these transformations, sometimes admits of other explanations; and when this is not the case, our conception of it is by no means sufficiently clear to justify the positive assumption of this, so called contact-action or catalytic force, which, after all, merely states the fact without explaining it"--_Gmelin's Hand-book of Chemistry_, vol. i. p. 115.

[53] The history and symptoms of some epidemic diseases, such as cholera and influenza, are not inconsistent with the hypothesis that they are caused by the sudden development of animalcules from ova in the blood. But there is a total want of direct observation in support of this hypothesis.--_Dr. Williams' Principles of Medicine._

[54] Since writing the above, I have referred for information on this subject, and find, that the Anguillula aceti exhibits sexual distinctions; and that the ovaries of the females are situated on each side of the alimentary canal.--_Cyclo. Anat. and Phys. Art. Entozoa._

[55] Speaking of the examination of the infusory animalcules--Mr. Kirby says: "But to us the wondrous spectacle is seen, and known only in part; for those that still escape all our methods of assisting sight, and remain members of the invisible world, may probably _far exceed those that we know_."--_Bridgewater Treatise_, vol. i. p. 158.

[56] Mr. Owen has added another class, as the first, called Protelmintha, which comprises the cercariadae and vibrionidae.

[57] "It is probable that in the waters of our globe an infinity of animal and vegetable molecules are suspended, that are too minute to form the food of even the lowest and minute animals of the visible creation: and therefore an infinite host of invisibles was necessary to remove them as nuisances."--_Bridgewater Treatise_, vol. i. p. 159.

"When Creative Wisdom covered the earth with plants, and peopled it with animals, He laid the foundations of the vegetable and animal kingdoms with such as were most easily convertible into nutriment for the tribes immediately above them. The first plants, and the first animals, are scarcely more than animated molecules,* and appear analogues of each other; and those above them in each kingdom represent jointed fibrils."+--_Bridgewater Treatise_, vol. i. p. 162.

* Globulina and Monus. + Oscillatoria and Vibrio.

[58] "A treatise which should present a systematic arrangement of all the diseases of plants, giving in detail the exact history of each, and adding the means of preventing and curing them, would certainly be of the greatest utility to agriculture." --_Essay on the Diseases of Plants, Count Philippo R['e], translated into Gardener's Chron._

[59] "Plenck published a treatise on Vegetable Pathology, in which he divided diseases into eight classes: 1. External injuries; 2. Flux of juices; 3. Debility; 4. Cachexies; 5. Putrefactions; 6. Excrescences; 7. Monstrosities; and 8. Sterility. And he concludes with an enumeration of the animals which injure plants."--_Essay on the Diseases of Plants, Gardener's Chronicle._

[60] The Bunt. "This disease appears at the moment of the germination of the plant. The affected individuals are of a dark green, and the stem is discoloured. As the ears are issuing from the sheaths, their stalks are of a dark green, but very slender. When the ear has fully grown out, its dull, dirty colour, causes it to be immediately distinguished from the healthy ones, and it soon turns white."--_Essay on the Diseases of Plants._

[61] _Vidi_ understood.

[62] "At the close of the year 1665," says Dr. Hodges, "even women, before deemed barren, were said to prove prolific."

"After the cessation of the Black Plague, a greater fecundity in women was every where remarkable--a grand phenomenon, which from its occurrence after every destructive pestilence proves to conviction, if any occurrence can do so, the prevalence of a higher power in the direction of general organic life. Marriages were almost without exception prolific; and double and treble births were more frequent than at other times."--_Hecker_, p. 31.

[63] It is stated that on the decline of the Plague, 1665, those who returned early to London, or new comers, were certain to be attacked. In proof of this the 1st week of November, the deaths increased 400, and "physicians reported that above 3000 fell sick that week, mostly new comers."

See also Dr. Copland's Dict. Pract. Med. Epidemic and Endemic Diseases.

"The hardy mountaineer is a surer victim of paludal fever, whether he visits the low countries of the tropics, or the marshes of a more temperate climate, than the feebler native of those countries."--_Dr. R. Williams on Morbid Poisons._

[64] "Substances presented to the gastro-intestinal surfaces, are mixed up with various secretions, mucus, saliva, gastric juice, bile, pancreatic liquor, and special exudations from the peculiar glands of each successive section, while aerial poisons, unmixed and unfettered, are applied at once to a surface on which, behind scarcely a shadow of a film, circulates the blood prepared, by the habitual action of the respiratory function, to absorb almost every vapour, and every odour, which may not be too irritating to pass the gates of the _glottis_."--_Mitchell on Fevers._

[65] Hecker on the "Black Death."

[66] The stomach in some cases is no doubt the medium by which some diseases are contracted. It is well known, that in many places the water induces diarrhoea, the permanent residents, however, may not suffer, but all new comers are more or less affected by drinking it.

[67] "Similar effects have been experienced from the use of mouldy provisions."--_Dr. Lindley's Vegetable Kingdom._

[68] "Untold numbers die of the diseases produced by scanty and _unwholesome food_."--_Southey._

A large, nay, a most extensive adulteration of flour with plaster of Paris was detected not many years since. The flour was supplied by a contractor for the manufacture of biscuits for the navy.

[69] See Southey's Doctor, vol. ii. interchapter vi. p. 115, for an illustration of this subject.

[70] Both these patients died.

[71] "A good part of the clove trees which grew so plentifully in the island of Ternate, being felled at the solicitation of the Dutch, in order to heighten the price of that fruit, such a change ensued in the air, _as shewed the salutary effect of the effluvia of clove trees and their blossoms; the whole island, soon after they were cut down, becoming exceeding sickly_."

[72] The observation is originally taken from the City Remembrancer, 133.

[73] See Hamilton's History of Medicine, vol. i. p. 4.

[74] Feuchtersleben's Medical Psychology, p. 176, 177.

[75] Ibid. p. 321.

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CHANGES MADE AGAINST PRINTED ORIGINAL.

Page 136. "the idea of Protophyta, or first plants": 'Prolophyta' in original.

Page 140. "an extensive bearing of each individual part": 'indivdual' in original.