Part 15
The little larva has not been seen emerging from the egg-case, but probably, as in the case of the meat- or blow-fly, _Musca vomitoria_, the eggshell splits longitudinally and the maggot pushes its way out. The length of the newly-hatched larva in its first stage (or instar) is seven-hundredths of an inch, and it remains in this stage about twenty-four hours, when it casts its skin and appears as a larger maggot three-twentieths of an inch long. In this condition it remains from twenty-four to thirty-six hours. After a second moult the maggot attains the length of one-quarter of an inch, and in this stage it remains five or six days. During its life the larva moves actively about amongst its surroundings, eating up the decaying matter, but avoiding bits of straw and hay. There is some evidence to believe that, if pressed for food, larvæ may devour one another. After living altogether some five to seven days, the larva somewhat suddenly turns into a dark brown pupa or chrysalis. The transition takes place very rapidly--in the course of a few minutes--and the pupa remains enclosed in the last larval skin. After another period of five to seven days in normal circumstances the insect hatches out, at first running around with soft and baggy wings, which, however, soon stretch out, harden, and dry. It is worthy of note that whereas Howard found the complete metamorphosis to take ten days, and Packard from ten to fourteen days, in the cooler climate of Manchester Hewitt finds it takes from twenty to thirty days. The last named gives some interesting particulars as to the effect of the weather upon the rate of development. It is believed that many flies pass the winter in the pupa state; the adult fly also survives the cold weather hidden away in cracks and crevices, from which it may from time to time emerge when the sun shines warmly.
When the larvæ are reared in too dry manure, they attain only one-half their usual size. Too direct warmth and the absence of moisture and available semi-liquid food also tend to dwarf them.
A word may be said about the distribution of the insect. It is practically cosmopolitan. As Mr. Austen records:
‘The British Museum collection, though very far from complete, includes specimens from the following localities: Cyprus; North-West Provinces, India; Wellesley Province, Straits Settlements; Hong Kong; Japan; Old Calabar; Southern Nigeria; Suez; Somaliland; British East Africa; Nyassaland; Lake Tanganyika; Transvaal; Natal; Sokotra; Madagascar; St. Helena; Madeira; Nova Scotia; Colorado; Mexico; St. Lucia; the West Indies; Pará, Brazil; Monte Video, Uruguay; Argentine Republic; Valparaiso, Chili; Queensland; New Zealand.’
It is carried all over the world in ships and trains, and seems to be equally at home in the high latitudes of Finmark or in the humid heat of Equatorial Brazil.
The diseases which flies convey from man to man--which rendered them by no means the least formidable of the plagues of Egypt, and fully justified Beelzebub’s title of the ‘Lord of Flies’--are for the most part conveyed mechanically. The proboscis acts as an inoculatory needle. No part of the life-history of the disease-causing organism must necessarily be carried on in the body of the fly; it is conveyed mechanically and without change from an infected to a healthy subject. The mouth parts can pick up the anthrax bacillus, and if the fly then alight upon a wounded surface it will set up woolsorter’s disease. It, together with the flea, is accused of transmitting the plague bacillus, not only from man to man, but from rat to man. Flies are active agents in disseminating cholera; and anyone who has watched them clustering around the inflamed eyes of the children in Egypt, or in Florida, will not readily acquit them of being the active agents in the spread of inflammatory ophthalmia or of ‘sore eye.’
It is worthy of note that after exhaustive experiments on the tsetse fly (_Glossina palpalis_), which conveys that most fatal of diseases, sleeping-sickness, Professor Minchin and his colleagues, Mr. Gray and Mr. Tulloch, have come to the conclusion that the Protozoon (_Trypanosoma gambiense_) which causes the disease does not--as might be expected--pass through certain stages of its life-history in the fly, but is mechanically conveyed upon the biting mouth parts of the insect. The deadly parasite is, indeed, so easily cleaned off these appendages that a single bite is sufficient to wipe them off. A tsetse fly which has bitten an infected person will set up the disease in the next person (or monkey) it bites; but the insertion of the proboscis, quick and instantaneous as it is, serves to clean it--to wipe off adhering trypanosomes, and if it now bite a second person (or monkey), it fails to convey the disease. This is a most important discovery, and contrary to what we should have expected; but our knowledge of the history of the genus _Trypanosoma_ is still too small to justify generalization, difficult as it is to avoid it. The diseases which in our country are disseminated by flies are all bacterial and all mechanically conveyed.
In passing, it is worth recording that, contrary to the usual statement that tsetse flies are confined to the continent of Africa, Captain R. M. Carter[8] has recently brought some back from the Tabau River and from other localities in South Arabia. Mr. Newstead has recognized the specimens as belonging to the species _Glossina tachinoides_. It evidently does not live on big game here, since, except the gazelle, game is absent. The Bedouins say that it bites donkeys, horses, dogs, and man, but not camels or sheep. It is at times so troublesome as to force the natives to shift their camps.
The common house-fly has been known for some time to be an active agent in the dissemination of bacterial diseases. In intestinal disorders--such as cholera and enteric fevers, which are caused by micro-organisms, the flies convey the bacteria from the dejecta of the sick to the food of the healthy. In the recent war in South Africa they are described in the standing camps as dividing their activities ‘between the latrines and the men’s mess-tins and jam rations.’[9] In the Spanish-American War in Cuba, and in the South African War, and in several recent outbreaks of enteric fever in the British army in India, flies have been proved to be the carriers of the _Bacillus typhosus_. Dr. Veeder[10] writes:
‘In a very few minutes they may load themselves with dejections from a typhoid or dysenteric patient, not yet sick enough to be in hospital or under observation, and carry the poison so taken up into the very midst of the food and water ready for use at the next meal. There is no long roundabout process involved. It is very plain and direct; yet when thousands of lives are at stake in this way the danger passes unnoticed.’
Similar records come from the Boer camp at Diyatalawa in Ceylon. The bacilli are conveyed direct, just as they might be by an inoculating needle. They do not pass into the body of the fly, neither do they undergo any part of their life-history in its tissue.
Dr. Sandilands[11] has recently investigated outbreaks of epidemic diarrhœa. He points out that the prevalence of diarrhœa follows the earth’s temperature, and does not follow the temperature of the atmosphere. It is a well-known fact that this illness is more prevalent in the houses of the poor than in the mansions of the rich. As Dr. Newsholme, late Medical Officer of Health for Brighton, said:
‘The sugar used in sweetening milk is often black with flies which have come from neighbouring dust-bins or manure heaps; often from the liquid stools of diarrhœa patients in the neighbouring houses. Flies have to be picked out of the half-emptied can of condensed milk before it can be used for the next meal. When we remember the personal uncleanliness of some mothers, and that they often prepare their infants’ food with unwashed hands, the inoculation of this food with virulent colon bacilli of human origin ceases to be a matter of surprise.’
Compared with cow’s milk, which nourishes a very numerous progeny of bacteria, the bacterial content of Nestlé’s milk is very low, according to Dr. Sandilands. In certain seasons the cow’s milk is exposed to temperatures which favour an enormous multiplication of bacteria, and yet it is not then a frequent source of diarrhœa--in fact, mere numbers have little or no influence on the incidence of the illness. The greater number of cases are due to infection conveyed from some patient in the near neighbourhood and conveyed mechanically by flies.
The great attraction of the sweetened condensed milk for flies to some extent explains the greater prevalence of infantile diarrhœa among children fed on this preparation.
As was stated above, one of the most remarkable features in the prevalence of infantile diarrhœa is that it follows the rise and fall of the earth’s temperature, and not that of the air. In the same way the number of house-flies does not reach its maximum with the first burst of hot weather. The prevalence of these insects follows rather than coincides with periods of great heat. The flies, in fact, lag behind the air temperature and persist for a time after the hot weather has ceased. In other words, the meteorological conditions associated with an increase or a diminution of the prevalence of diarrhœa exercise a similar influence on the prevalence of flies.
The transference of the _Filaria bancrofti_, whose presence in the human body in the adult stage is associated with various diseases of the lymphatics, the most pronounced of which is the terrible elephantiasis, is due to more than one species of gnat or mosquito. It is true that no one has ever seen the actual transference of the _Filaria_ from the biting organs of the _Culex_, _Anopheles_, _Panoplites_, or _Stegomyia_ into the human body, but the circumstantial evidence is so strong that on it any jury would convict. Noè and Grassi have demonstrated a similar mode of infection for the _Filaria immitis_, which exists in the adult stage in such incredible numbers in the cavity of the right side of the heart of dogs, especially in tropical and in sub-tropical countries, that it is difficult to see how the circulation can be maintained at all. It is therefore interesting to note that the proboscis of our common house-fly frequently harbours a larval nematode which has been described by Carter[12] under the name of _Habronema muscæ_; and again (if it be the same species) by Generali[13] under the name _Nematodum sp._ (?), and again by Piana,[14] who is inclined to think it is the larval form of _Dispharagus nasutus_ (Rud.). What the further history of this parasite is we do not conclusively know, but, judging by analogy--and in the case of the grosser parasites it is not always wise to do that--the nematode probably develops in some higher animal which eats the fly. Piana brings forward a good deal of evidence that this is the domestic fowl.
Another parasite which attacks flies is the fungus or mould _Empusa muscæ_, whose growth is fatal to the insect. The hyphæ penetrate into the body, and as they grow weaken the fly until it is unable to lift a leg, but remains glued by its viscid feet to the object upon which it rests. The fungus spreads and radiates out in all directions, covering the fly as with a velvety pile, and giving off countless minute spores, which are blown away, to alight, if they are lucky, on a further victim.
I think enough has been said to prove that flies are a very real danger to our community. I have refrained from giving the appalling statistics of our infant mortality, partly because of the difficulty of discriminating between the claims of the flies and those of other agencies which affect the lives of our babies--_e.g._, the insurance companies which do a large trade in insuring infants. Legislation has not attempted to control the latter. Sanitation might do much to destroy the former. In well-administered towns slaughterhouses no longer ‘fill our butchers’ shops with large blue flies’; they have been replaced by abattoirs, under proper inspection. Stables should also be segregated or controlled. The practice of backing the mansions of Berkeley Square by stable yards should either be given up, or the manure-heaps in which the flies breed should be under cover so close as to prevent the access of the fly. A layer of lime spread over the manure effectively prevents the fly laying. Creolin, in its cheap commercial form, is also recommended, sprayed over the manure-heaps every two or three days. It not only deters flies from ovipositing, but should they succeed in doing so it kills the resulting larvæ.[15]
Ross has shown us how to clear Ismailia of malaria; the Americans have rid Havana, for the first time in a century, of yellow fever; the same could be done with flies, if only the people liked to have it so. The motorcar, with all its destruction of nervous tissue, its prevention of sleep, its danger to life and to limb, has one great merit--it affords no nidus for flies.
CAMBRIDGE
‘_Our dear Cambridge._’ COWLEY: ‘On the Death of Mr. William Hervey.’
The grant of a charter to the Victoria University in 1880 marked the beginning of a new era in English education. Not to speak of Scotland and Wales, there are in England to-day six Universities which bring the new learning and the old to the very doors of the vast populations which surround their seats. Birmingham claims the Midlands; Manchester, Liverpool, Leeds, and Sheffield instruct the manufacturing and commercial centres of the North; while the University of London, full of new aspirations, does its best for the huge and somewhat apathetic population of the capital. The calculated prodigality of the State endowments of Germany, the individual generosity of the citizens of the United States, the vigour of the young Universities of Canada, have smitten the national conscience, if not with shame, at least with fear. But, while so powerful a lever as the dread of industrial decay may have been necessary to overcome the intellectual inertia of the country, the consequent impetus given to the study of science and (it may be hoped) of letters is not dying away, but rather taking permanent shape; and it is now impossible to say, as was said in 1903 by one of the members of the Mosely Educational Commission, that ‘in this country ... we seem to be doing nothing for its own sake, and least of all in education.’
The new edition of the ‘Endowments of the University of Cambridge’ suggests other, though kindred, reflections. The book has for its basis a series of documents, beginning with the year 1293, and ending with the year 1904. The learned Registrary has prefaced the account of each bequest with an explanation, and, by his discriminating comment, has invested his material with something of that charm which characterizes all his work. In one aspect his book serves, and is intended to serve, as a history of the progress of education in Cambridge; and the large amount of new matter which has been incorporated since the previous edition of the ‘Endowments’ in 1876 is, in this aspect, highly satisfactory. Yet, though it is a mistake to suppose that the flow of benefactions to the ancient Universities has entirely ceased, the fact remains that Cambridge has twice appealed--once in 1898, and once again in the spring of 1904--for help, without which she cannot meet her national responsibilities. Oxford has at last been constrained to confess that she is in a similar, if not yet so dire, a strait; and it is easy to understand the effort which it has cost her, as well as her sister University, to sue _in formâ pauperis_.
In truth, the neglect, almost absolute, of Oxford and Cambridge, while the new Universities are finding generous benefactors, either leads to the conclusion that the old Universities are condemned and found wanting, or has its origin in a profound misconception of their efforts and resources. It may be urged that neither alternative is true; that the needs of the new Universities are more urgent, and that the needs of Oxford and Cambridge will in turn receive attention. But a delay of a few years may in these days involve damage which will not be repaired for more than one generation. Of Cambridge, at any rate, it is asserted that she is at the end of her means, that in the last forty years she has, in her efforts at development, strained her resources to the utmost, and that without assistance, which, to be effectual, must be both prompt and generous, no further advance is possible. Science has emptied the University chest, yet, as the late master of Trinity Hall said, ‘Science is still hungry and aggressive.’ As the result of her straitened resources Cambridge can no longer satisfy the just demands either of science or of letters. When we compare this state of things with that in Germany, where the University of Berlin enjoys a State endowment of £170,000 per annum, or in the United States, whose Universities have received from private benefactors alone £42,000,000 sterling in the last thirty years, apart from large funds provided by the State, we are forced to recognize that much yet remains to be done in England.
It is not difficult to suggest some reasons for the comparative neglect of the older Universities in the matter of benefactions. In the first place, neither of them can appeal to local patriotism; and an appeal on the wider ground of national efficiency is not so easily nor so effectively pushed home. Next, it is hard to imagine that a University whose colleges enjoy a corporate income of something like £300,000 a year can be in serious want of funds. Moreover, if this deficiency really exists, it is generally regarded as the result of the squandering of revenue on an extravagant system of ‘prize fellowships’--that is, fellowships given as the reward merely for a high place in examination, and held by barristers, doctors, and civil servants, professors and lecturers in other Universities, and even successful men of business--persons who do not contribute in any way to the efficiency of the University as a teaching or as an investigating body.
* * * * *
We propose briefly to examine the University balance-sheet, the college system, and the question of the fellowships, and to endeavour to give the candid inquirer some ground for a judgment on the claims of Cambridge. But we must first discuss what is perhaps the most serious obstacle to the satisfaction of her needs. This obstacle is the belief, apparently ineradicable, that the older Universities teach and care for nothing but the ancient languages, theology, and mathematics. For the persistence of this belief the daily press and public speakers are in a great measure to blame. Scarcely a week passes without an allusion which betrays, if not a culpable levity, a most unfortunate ignorance. Cambridge men have listened with amazement to the covert attacks on Cambridge science, and have wondered how long it may be before Cambridge letters are also disparaged. Of late, too, another note has been heard; and, notwithstanding the just aspiration of the new Universities to a many-sided activity, alike in the literary and scientific fields, an attempt, which must be stigmatized as ungenerous and illiberal, has been made in the press and on the public platform to limit the functions of the ancient Universities, and to drive them back into the grooves of the thirties and forties, from which Cambridge, to say nothing of Oxford, has so completely escaped. Whatever the reason may be, it is at least certain that Cambridge is frequently written and spoken of as if she were still the Cambridge of 1850.
It has been suggested, even in responsible journals, that Oxford and Cambridge would do well to keep to the older lines of education, and to leave newer studies to their younger rivals. The obsession of men’s minds by an ideal which passed away half a century ago can alone account for the impression that the policy of restriction to the ancient learning is in any way possible, or has been possible for these fifty years. Those who know Cambridge may well be astonished that responsible persons should gravely speak of the University of Newton and Charles Darwin, of Maxwell and Rayleigh, as still shrouded in medieval shadow.
It cannot be too often repeated that since the Commission of 1850, or rather since the promulgation of the new statutes in 1856, the University has advanced without pause to claim as her own the whole field of modern knowledge; and that it is the rapidity of her advance which has depleted her treasury. The state of things before 1850 need here be referred to only for purposes of contrast. The only avenue to an honours degree was then the Mathematical Tripos, or, for students of classics, the Mathematical combined with the Classical Tripos. Science formed no part of the regular course of instruction. Adam Sedgwick himself, pre-eminent geologist as he afterwards became, knew nothing of geology when admitted to his professorship. When he was appointed to his chair, classics, mathematics, and, in a less degree, theology and law, were well endowed; but effective provision for modern studies or for science there was none. In 1851 was founded the Disney professorship of archæology, and the creation of this chair may fairly be considered to be the first step towards the recognition of the sciences of ethnology and anthropology. The imperial value of ethnological and anthropological research is incontestable, and to this research no more important contribution has been made than by the bands of Cambridge travellers and students.
Mention has been made in the first place of the studies more closely related to the ‘humanities,’ because it does not seem generally to be realized how thoroughly even the ancient learning is to-day imbued by the scientific spirit. But, so early as the year 1851,[16] new avenues to an honours degree were opened by way of the Moral Sciences Tripos (embracing at present psychology, logic and methodology, political economy, ethics, metaphysical and moral philosophy and psychophysics), and the Natural Sciences Tripos (embracing chemistry, physics, mineralogy, geology, botany, zoology, human anatomy, and physiology). In 1857 the Sadlerian professorship of pure mathematics was founded by the consolidation of an old endowment; and Cayley was the first occupant of the chair. In 1863 the block of buildings known as ‘The Museums’ was commenced, with a view to providing accommodation for the professors of the natural sciences; additions were made to the original buildings in 1877, 1880, 1882, 1884, and 1890, as new branches of science became important. In 1858 the ‘Civil Law Classes’ were replaced by the Law Tripos; the professor of civil law and the Downing professor of the laws of England were given a colleague by the creation of the Whewell professorship of international law in 1867; and the Law School has since 1904 possessed a worthy habitation, built partly at the expense of the University, partly by the help of eminent Cambridge lawyers, and completed by the generous donation of the law library by Miss Squire. In 1866 the professorship of zoology was founded.