On the mode of communication of cholera
Part 11
In the autumn of 1853, the cholera was prevailing extensively at Hamburgh, and in nearly all the ports of the Baltic, whence a number of ships were arriving every day in the Tyne. The first cases of cholera commenced, with diarrhœa, on the 27th and 28th August, at Bell Quay, on the banks of the Tyne, three miles below Newcastle. One of the patients from Bell Quay was taken worse whilst on a visit to her mother at Newcastle: she died on 2nd September. Her mother was taken ill the same evening, and died on the following day. Other cases occurred in Newcastle on the 1st and 2nd of September, having no connexion with these. A ship from Bremen was lying at Bell Quay, opposite the house where the first cases occurred; but there had been no illness on board this ship, and the precise way in which the cholera was introduced on this occasion, is not known.
The disease soon spread to an extent almost unprecedented in this country: by the 15th of September the deaths exceeded a hundred a day. In nine weeks there were 1,533 deaths from cholera in a population of 86,114, being 178 to each 10,000 inhabitants; but the greater number of these deaths occurred in a few days, as 1001 took place from the 13th to the 23rd Sept. inclusive.[23]
Gateshead, which is situated opposite to Newcastle, on the other side of the Tyne, is supplied with the same water; and in 1849 it shared with that town a comparative immunity from cholera, whilst in the autumn of 1853, 433 persons died of that disease out of a population of 26,000, or thereabouts, being 166 to each 10,000 inhabitants.
The lowest streets in Newcastle and Gateshead are about five feet above high-water mark; and only a few streets are situated at this level, for the banks rise very abruptly, at a little distance from the river, on both sides. A great portion of each town is elevated nearly 200 feet above the river, and some parts are nearly 300 feet high; yet the Water Company supplies all these districts, and all were severely visited by the cholera, which on this occasion spared no class of the community. In the districts which are most crowded, the mortality was greatest, the deaths being much more numerous in the parishes which contained a great number of tenements consisting of a single room, than in those which consisted chiefly of houses occupied by one family.[24] This, however, is quite in accordance with the principles which I am throughout endeavouring to explain. A great deal of stress is laid, very properly, by the Commissioners who have reported respecting this outbreak, on the ill-arranged buildings, the defective drainage, and want of privy accommodation, in Newcastle; but it must be remembered that all these evils existed in 1849, when Newcastle escaped with less cholera than most towns,—to a greater extent than they did in 1853, for many improvements had taken place in the meantime.
In consequence of a great outcry on the part of the public, who naturally connected the great fatality of cholera in some measure with the turbidity and offensive smell of the drinking water, the Company entirely ceased to draw water from the Tyne on the 15th September; and although the Tyne water was not entirely out of the pipes for a day or two, the deaths, which had been rapidly increasing, began to diminish on the 17th, and were lessened considerably by the 20th. The following is the course of the mortality in Newcastle, in the most fatal part of the epidemic; and it began to decline at exactly the same time in Gateshead:
September 12 13 14 15 16 17 18 19 20 21 22 23 DEATHS 38 59 90 106 114 103 103 111 85 68 82 60.
The late General Board of Health directed one of their medical inspectors, Dr. Waller Lewis, to make minute inquiry as to the relative effects produced by the use of pure spring water, and that of the Water Company, during the epidemic of cholera in Newcastle; and it is much to be regretted that the inquiry was not carried out. To have conducted the inquiry through the whole of Newcastle and Gateshead would not have entailed a quarter as much labour as my investigations in Lambeth, Newington, and the Borough. Dr. Lewis called on Mr. Main, the secretary of the Water Company, and they made an inquiry in certain houses, taken at random, through three streets, and also in Greenhow Terrace, where a severe outbreak of cholera had occurred, although it was not supplied by the Company, but had what was reported to be good spring water. Dr. Lewis gave up the inquiry because he could not find two places exactly alike in all their physical conditions,—one place supplied with spring water, the other by the Company. He made no report of what he had done; but Mr. Main sent a paper on the subject of this commenced inquiry to the Pathological Society of Newcastle, an abstract of which appeared in the “Medical Times and Gazette”.
By adding Greenhow Terrace to the streets partly supplied by the Company, and by including cases of cholera, fatal or otherwise, with those of mere diarrhœa, Mr. Main was able to show a result apparently in favour of the Company’s water. He was good enough, however, to send me a copy of his paper, which contains the details of the inquiry as far as it extended; and I found, on perusing it, that, leaving out Greenhow Terrace, which is not supplied by the Company at all, there was no case of cholera, either fatal or otherwise, and no case, even of approaching cholera, in any house which was not supplied with the Company’s water. All the deaths and all the cholera occurred in the houses having this water, whilst in the houses having only pump-water, there was simply diarrhœa. In the workhouse, supplied by the Water Company, and having five hundred and forty inmates, there were twelve cases of cholera, or approaching cholera, and seven deaths; whilst in the military barracks, supplied from wells on the premises, and having five hundred and nineteen inmates, although there was a good deal of harmless diarrhæa, there was no cholera, nor any case of approaching cholera.
[Sidenote: CHOLERA AT MOSCOW.]
The communication of cholera by means of the water is well illustrated by the instance of Moscow, which was severely visited by that disease in 1830; but much less severely in the second epidemic. Subsequently to 1830 the greater part of the town, which is situated to the north of the Moscow river, obtained a supply of excellent water, conducted in pipes from springs at a distance; and the cholera in 1847 was chiefly confined to those parts of the town which lie to the south of the river, to which the new supply of water did not extend, and where the people had still only impure river water to drink.[25]
The above instances are probably sufficient to illustrate the widely-spread influence which the pollution of the drinking water exerts in the propagation of cholera.
[Sidenote: DIFFUSION OF THE CHOLERA POISON IN WATER.]
After the Registrar-General alluded, in the “Weekly Return” of 14th October last, to the very conclusive investigation of the effects of polluted water in the south districts of London, there was a leading article, in nearly all the medical periodicals,[26] fully admitting the influence of the water on the mortality from cholera. It may therefore be safely concluded that this influence is pretty generally admitted by the profession. It must not be disguised, however, that medical men are not yet generally convinced that the disease is actually communicated from person to person by the morbid matter being swallowed in the drinking water, or otherwise. It used to be the custom of medical authors to speak of three kinds of causes of a disease, viz. predisposing, exciting, and proximate causes. The proximate causes have been given up, as being the diseases themselves; but authors still divide causes into predisposing and exciting ones. It may be remarked, however, that in treating of certain communicable diseases, the cause of which is thoroughly understood, as syphilis and the itch, predisposing causes are never mentioned; and that they are rarely alluded to in treating of small-pox, measles, and scarlet fever, whilst they continue to be appealed to in explanation of the various continued fevers.[27] Now many medical men, whilst they admit the influence of polluted water on the prevalence of cholera, believe that it acts by predisposing or preparing the system to be acted on by some unknown cause of the disease existing in the atmosphere or elsewhere. The following amongst other reasons prove, however, that opinion cannot long halt here, and that, if the effect of contaminated water be admitted, it must lead to the conclusion that it acts by containing the true and specific cause of the malady.
In my inquiries in the south districts of London I met with several instances in which persons, especially maidservants and young men, died of cholera within a few days after coming from the country to a house supplied with water by the Southwark and Vauxhall Company. The Registrar of Waterloo Road (2nd) remarked as follows on this point, on 26th August last:—“This is the third successive case of fatal cholera, where the patients have recently come from the country. Similar instances have frequently attracted the Registrar’s notice.” I found that the houses in which these cases occurred were supplied by the above-named Company. The outbreak of cholera in the Baltic fleet, related at page 36, occurred within forty-eight hours after the polluted water had been taken on board. And lastly, if the contaminated water merely acted by predisposing or preparing the system to be affected by some other cause, it would be impossible to explain why nearly all the persons drinking it should be attacked together, in cases where a pump-well or some other limited supply is polluted, while the population around experience no increase of the malady.
All the evidence proving the communication of cholera through the medium of water, confirms that with which I set out, of its communication in the crowded habitations of the poor, in coal-mines and other places, by the hands getting soiled with the evacuations of the patients, and by small quantities of these evacuations being swallowed with the food, as paint is swallowed by house painters of uncleanly habits, who contract lead-colic in this way.
There are one or two objections to the mode of communication of cholera which I am endeavouring to establish, that deserve to be noticed. Messrs. Pearse and Marston state, in their account of the cases of cholera treated at the Newcastle Dispensary in 1853, that one of the dispensers drank by mistake some rice-water evacuation without any effect whatever.[28] In rejoinder to this negative incident, it may be remarked, that several conditions may be requisite to the communication of cholera with which we are as yet unacquainted. Certain conditions we know to be requisite to the communication of other diseases. Syphilis we know is only communicable in its primary stage, and vaccine lymph must be removed at a particular time to produce its proper effects. In the incident above mentioned, the large quantity of the evacuation taken might even prevent its action. It must be remembered that the effects of a morbid poison are never due to what first enters the system, but to the crop or progeny produced from this during a period of reproduction, termed the period of incubation; and if a whole sack of grain, or seed of any kind, were put into a hole in the ground, it is very doubtful whether any crop whatever would be produced.
[Sidenote: EXPERIMENTS OF DR. THIERSCH ANSWERS TO CERTAIN OBJECTIONS.]
Dr. Thiersch is of opinion, as appears by a discussion which has recently taken place at Munich, that the cholera evacuations are not at first capable of generating the disease; but that a decomposition takes place in them, and that in from six to nine days they become in a state to induce cholera. He founds this opinion on experiments which he performed by giving small quantities of the cholera evacuations to white mice. Although it is not contrary to all analogy that some change or development should take place in the cholera poison in the interval between its leaving one person and entering another, it is most probable that the fatal bowel complaint produced in white mice by Dr. Thiersch was not a specific disease, but the ordinary effect of putrifying ingesta. Many of the best attested instances of the communication of cholera are those, such as were related at the commencement of this work, where the patient is attacked in from twenty-four to forty-eight hours after first being near another patient, and although an interval of a week or so, often elapses between one case of the disease and those which follow, it is extremely probable that, in these instances, the evacuations remain the greater part of this time in a dry state on the soiled linen, without undergoing any change.
An objection that has repeatedly been made to the propagation of cholera through the medium of water, is, that every one who drinks of the water ought to have the disease at once. This objection arises from mistaking the department of science to which the communication of cholera belongs, and looking on it as a question of chemistry, instead of one of natural history, as it undoubtedly is. It cannot be supposed that a morbid poison, which has the property, under suitable circumstances, of reproducing its kind, should be capable of being diluted indefinitely in water, like a chemical salt; and therefore it is not to be presumed that the cholera poison would be equally diffused through every particle of the water. The eggs of the tape-worm must undoubtedly pass down the sewers into the Thames, but it by no means follows that everybody who drinks a glass of the water should swallow one of the eggs. As regards the morbid matter of cholera, many other circumstances, besides the quantity of it which is present in a river at different periods of the epidemic, must influence the chances of its being swallowed, such as its remaining in a butt or other vessel till it is decomposed or devoured by animalcules, or its merely settling to the bottom and remaining there. In the case of the pump-well in Broad Street, Golden Square, if the cholera poison was contained in the minute whitish flocculi, visible on close inspection to the naked eye, some persons might drink of the water without taking any, as they soon settled to the bottom of the vessel.
[Sidenote: THEORIES OF THE CAUSE OF CHOLERA.]
It is not necessary to oppose any other theories in order to establish the principles I am endeavouring to explain, for the field I have entered on was almost unoccupied. The best attempt at explaining the phenomena of cholera, which previously existed, was probably that which supposed that the disease was communicated by effluvia given off from the patient into the surrounding air, and inhaled by others into the lungs; but this view required its advocates to draw very largely on what is called predisposition, in order to account for the numbers who approach near to the patient without being affected, whilst others acquire the disease without any near approach. It also failed entirely to account for the sudden and violent outbreaks of the disease, such as that which occurred in the neighbourhood of Golden Square.
Another view having a certain number of advocates is, that cholera depends on an unknown something in the atmosphere which becomes localized, and has its effects increased by the gases given off from decomposing animal and vegetable matters. This hypothesis is, however, rendered impossible by the motion of the atmosphere, and, even in the absence of wind, by the laws which govern the diffusion of aeriform bodies; moreover, the connection between cholera and offensive effluvia is by no means such as to indicate cause and effect; even in London, as was before mentioned, many places where offensive effluvia are very abundant have been visited very lightly by cholera, whilst the comparatively open and cleanly districts of Kennington and Clapham have suffered severely. If inquiry were made, a far closer connection would be found to exist between offensive effluvia and the itch, than between these effluvia and cholera; yet as the cause of itch is well known, we are quite aware that this connection is not one of cause and effect.
Mr. John Lea, of Cincinnati, has advanced what he calls a geological theory of cholera.[29] He supposes that the cholera poison, which he believes to exist in the air about the sick, requires the existence of calcareous or magnesian salts in the drinking water to give it effect. This view is not consistent with what we know of cholera, but there are certain circumstances related by Mr. Lea which deserve attention. He says that, in the western districts of the United States, the cholera passed round the arenacious, and spent its fury on the calcareous regions; and that it attacked with deadly effect those who used the calcareous water, while it passed by those who used sandstone or soft water. He gives many instances of towns suffering severely when river water was used, whilst others, having only soft spring water or rain water, escaped almost entirely; and he states that there has been scarcely a case of cholera in families who used only rain water. The rivers, it is evident, might be contaminated with the evacuations, whilst it is equally evident that the rain water could not be so polluted. As regards sand and all sandstone formations, they are well known to have the effect of oxidizing and thus destroying organic matters; whilst the limestone might not have that effect, although I have no experience on that point. The connection which Mr. Lea has observed between cholera and the water is highly interesting, although it probably admits of a very different explanation from the one he has given.
[Sidenote: DURATION OF CHOLERA IN DIFFERENT PLACES.]
There are certain circumstances connected with the history of cholera which admit of a satisfactory explanation according to the principles explained above, and consequently tend to confirm those principles. The first point I shall notice, viz., the period of duration of the epidemic in different places, refers merely to the communicability of the disease, without regard to the mode of communication. The duration of cholera in a place is usually in a direct proportion to the number of the population. The disease remains but two or three weeks in a village, two or three months in a good-sized town, whilst in a great metropolis it often remains a whole year or longer. I find from an analysis which I made in 1849 of the valuable table of Dr. Wm. Merriman, of the cholera in England in 1832,[30] that fifty-two places are enumerated in which the disease continued less than fifty days, and that the average population of these places is 6,624. Forty-three places are likewise down in which the cholera lasted fifty days, but less than one hundred; the average population of these is 12,624. And there are, without including London, thirty-three places in which the epidemic continued one hundred days and upwards, the average population of which is 38,123; or if London be included, thirty-four places, with an average of 78,823. The following short table will show these figures in a more convenient form:—
No. of Places. Duration in Days. Average Population. 52 0 to 50 6,624 43 50 to 100000 12,624 33} 100 and upwards { 38,123 34} „ { 78,823
There was a similar relation in 1849 between the duration of the cholera and the population of the places which it visited; a relation which points clearly to the propagation of the disease from patient to patient; for if each case were not connected with a previous one, but depended on some unknown atmospheric or telluric condition, there is no reason why the twenty cases which occur in a village should not be distributed over as long a period as the twenty hundred cases which occur in a large town.
Even the duration of the cholera in a street, when compared to its duration in the individual houses, points to the same conclusion. A table has been published[31] in the report of the late discussion on cholera at Munich, which shows that whilst the epidemic remained three or four weeks in a street, it only remained six or seven days in houses where several people were attacked. Dr. Pettenkofer remarks, that “if the proximate cause of the disease had been generally diffused over a certain number of streets or a certain district, and its invasion had been opposed by individual disposition alone, one might have expected that both the cases of disease and the instances of death would have occurred in single houses, where many such appeared together, at similar periods of time throughout the whole street; but, supposing that the proximate cause of the disease was not general, but local, then it would act in such a manner that the period of time within which the disease would show itself in single houses would be very different from that which was applicable to the entire street.” The local cause in a house we know to be the illness of some individual, who, in many cases, has newly arrived from some place where the disease was prevailing.
[Sidenote: EFFECT OF SEASON ON THE PREVALENCE OF CHOLERA.]
Each time when cholera has been introduced into England in the autumn, it has made but little progress, and has lingered rather than flourished during the winter and spring, to increase gradually during the following summer, reach its climax at the latter part of summer, and decline somewhat rapidly as the cool days of autumn set in. In most parts of Scotland, on the contrary, cholera has each time run through its course in the winter immediately following its introduction. I have now to offer what I consider an explanation, to a great extent, of these peculiarities in the progress of cholera. The English people, as a general rule, do not drink much unboiled water, except in warm weather. They generally take tea, coffee, malt liquor, or some other artificial beverage at their meals, and do not require to drink between meals, except when the weather is warm. In summer, however, a much greater quantity of drink is required, and it is much more usual to drink water at that season than in cold weather. Consequently, whilst the cholera is chiefly confined in winter to the crowded families of the poor, and to the mining population, who, as was before explained, eat each other’s excrement at all times, it gains access as summer advances to the population of the towns, where there is a river which receives the sewers and supplies the drinking water at the same time; and, where pump-wells and other limited supplies of water happen to be contaminated with the contents of the drains and cesspools, there is a greater opportunity for the disease to spread at a time when unboiled water is more freely used.
In Scotland, on the other hand, unboiled water is somewhat freely used at all times to mix with spirits; I am told that when two or three people enter a tavern in Scotland and ask for a gill of whiskey, a jug of water and tumbler-glasses are brought with it. Malt liquors are only consumed to a limited extent in Scotland, and when persons drink spirit without water, as they often do, it occasions thirst and obliges them to drink water afterwards.