Source: Snow, John. Medical Times and Gazette 11 (1855):
31-35 (Part 1, July 14, 1855), 84-88 (Part 2, July 28, 1855).
Further remarks on the mode of communication of cholera; including some comments on the recent reports on cholera by the General Board of Health
(A great part of this Paper was read at the Epidemiological Society in May and June, 1855.)
In a paper which I had the honour to read to this Society in 1851,* I enumerated various circumstances connected with the pathology of Cholera, and with its progress as an epidemic, which led me to the conclusion that it is propagated by the morbid poison which produces it being accidentally swallowed; that this morbid poison becomes multiplied and in-[31/32] creased in quantity on the interior surface of the alimentary canal and that it passes off in the ejections and dejections to produce fresh cases of the disease in those who happen to take the morbid matter into the stomach. I explained what great facilities there are for the cholera evacuations being accidentally swallowed in the crowded habitations of the poor, where the inmates cook, eat, live, and sleep in the same apartment, and pay little regard to washing the hands, since these evacuations are almost devoid of colour and odour, and are usually passed involuntarily in the latter stages of the disease. It is in the families of the poor that cholera is often observed to pass from one individual to another, while in cleanly dwellings, where the hand-basin and towel are in constant use, and where the rooms for cooking, eating, and sleeping are distinct from each other, the communication of cholera from person to person is rarely observed. In the houses of the poor, also, the disease is hardly ever contracted by medical, clerical, and other visitors, who do not eat or drink in the sick-room, while it often fares differently with the social visitor, who comes either to see the patient or attend his funeral. (*Published in Medical Times and Gazette, 1851, Vol. II.)
The cholera has visited the mining districts of this country with unusual severity, in each of the epidemics we have had. The following is the explanation of this circumstance:--The pits are without any privies, and the excrement of the workmen lies about almost everywhere, so that the hands are liable to be soiled with it. The pitmen remain under ground eight or nine hours at a time, and invariably take food down with them into the pits, which they eat with unwashed hands, and without knife and fork; therefore, as soon as a case of cholera occurs among any of the pitman, the disease has unusual facilities of spreading in the way I have pointed out.
In my former paper I also showed that the cholera evacuations have the property of communicating the disease after being mixed with the drinking-water of the people, and I related a number of instances in which sudden and severe outbreaks of the malady occurred in the epidemics of 1832 and 1849 among persons using the water of ditches and pump-wells contaminated with excrementitious matters. It is particularly to be remarked that, in those instances, there were one or two cases of cholera in the community where evacuations polluted the water, just before the great out-break. I also related a number of facts to show that cholera was communicated through the water supplied to many districts of London, and to several other towns where the water was obtained from a river receiving the sewage of the town. This division of my views on cholera which refers to its communication through the medium of drinking water, has apparently obtained a greater amount of attention from the Profession, than my views respecting its more immediate communication by the cholera poison being swallowed without the water. While I speak on this division of the subject, however, I must beg the Society to bear in mind also the other part of my views, first alluded to, for I am well aware that the part which relates to polluted water will not of itself explain the whole progress of the disease as an epidemic.
The epidemics of 1853 and 1854 have furnished numerous examples of the communication of cholera by means of water quite as striking as those which I related in my former paper; but I shall be content on the present occasion to describe only a single example which occurred on a large scale, and shall merely make such remarks on some other instances, as may be necessary to elucidate the way in which the water produces its effects.
The whole of the south districts of London, with the exception of the Greenwich district, and part of the Lewisham and Rotherhithe districts, are supplied with water by two water companies, one called the Lambeth Company, and the other the Southwark and Vauxhall Company. The population of the districts supplied by these two water companies, amounted in 1851 to nearly half-a-million. Now throughout the greater part of the districts supplied by these two water companies, the supply is intimately mixed, the pipes of both companies going down all the streets, and into almost all the courts and alleys. The water companies were at one time in active competition, and any person paying the rates, whether landlord or tenant, could change his water company as easily as his butcher or baker, and although this state of things has long since ceased, and the companies have come to such an arrangement that the people cannot change their supply, yet the result of the former competition remains. There is here and there a row of houses having the same supply, but very often two contiguous houses are supplied differently. There is no difference in the circumstances of the people supplied by the two companies; each company supplies both rich and poor alike.
In 1849 the water supplied by the two companies was nearly the same; that of the Lambeth Company was obtained from the Thames, close to Hungerford Suspension Bridge; and that of the Southwark and Vauxhall Company at Battersea-fields: each kind of water contained the sewage of London, and was distributed with very little attempt at purification, as the most superficial examination was enough to show. The cholera in 1849 was almost equally severe in the districts which were entirely supplied by the Southwark and Vauxhall Company, and those which were partly or chiefly supplied by the Lambeth Company. This latter company had no district, or even sub-district, exclusively to itself, and although it has since extended its supply to the sub-districts of Streatham, Norwood, Dulwich, and Sydenham, these villages are chiefly supplied by pump-wells.
Between the epidemic of 1849, and that of 1853, a very important change was made in the water supply of a great portion of the south districts of London. The Lambeth Company removed their works in 1852 from the neighbourhood of Hungerford Bridge to Thames Ditton, which is situated above Teddington Lock, and is, therefore, beyond the influence of the tide, and out of reach of the sewage of London.
Dr. Farr turned his attention to the influence of the water-supply on the mortality from cholera in London soon after my pamphlet, containing remarks on the subject, appeared in 1849. He returned to the subject in the latter part of 1853, and the weekly returns of that time contain some tables, showing that the districts, partly supplied with the improved water from Thames Ditton, suffered a lower mortality than those supplied exclusively with the water from Battersea-fields. It was desirable, however, to investigate this matter more in detail, and to find out, if possible, what was the actual water-supply in the houses in which fatal attacks occurred. I was unable to do this in the epidemic in the last quarter of 1853, but when the cholera returned to London in the following summer, I resolved to call myself at the houses in which deaths might occur, in the districts where the water-supply is intermingled in the way I have explained. The addresses of the persons who died of cholera during the first four weeks of the epidemic of 1854 were published in the weekly returns, and on applying to Dr. Farr, I was kindly permitted to copy those of the persons whose deaths were registered during the next three weeks. My inquiries thus extended over the first seven weeks of the epidemic, that is, from the 8th of July to the 26th of August. The number of deaths I inquired after personally amounted to 658; but as the water companies make no return of the number of houses they supply in particular parishes or districts, it was necessary, in order to find out the exact influence of the water, to extend the inquiry to all the districts to which the water of either company is distributed, in order that the number of fatal attacks might be compared with the entire number of houses supplied by each company, as shown by their returns to Parliament at the conclusion of l853, namely, 40,046 by the Southwark and Vauxhall Company, and 26,107 by the Lambeth Company.
I was assisted by a Medical man, Mr. Whiting, in making the inquiries respecting the water-supply in certain districts supplied only by the Southwark and Vauxhall Company; but I made the inquiry myself in all the districts to which the water of the Lambeth Company extends; so that Mr. Whiting's part of the inquiry, which he conducted very carefully, was merely to ascertain whether the houses, in which fatal attacks took place, were supplied by the Southwark and Vauxhall Company, or by a pump-well, or some other local supply. In the case where persons died in an hospital or a workhouse, to which they had been removed after the attack, the water-supply of the houses from which they had been removed was ascertained.
In stating the results of these inquiries, I shall divide the seven weeks over which they extended into two periods, giving the result of the first four weeks of the epidemic first, and then that of the succeeding three weeks, as the cholera was more exclusively caused by the water in the beginning of the epidemic than afterwards, for reasons that I shall state. I shall also treat separately of the groups of districts, accord-[32/33] ing as they were supplied by only one of the companies, or by the two combined.
In the first four weeks of the epidemic there was not a single death from cholera registered in the sub-districts supplied by the Lambeth Company, and not supplied by the other company. In the sub-districts, in which the supply of the two companies intermingled, in the way I have explained, there were 134 deaths from cholera registered during this period, and I ascertained, by calling at the respective houses in which the fatal attacks occurred that the water supply in 115 of the cases was that of the Southwark and Vauxhall Company, in 14 cases that of the Lambeth Company, in 2 cases from pump-wells, and 1 direct from the river, and in 2 instances it was not ascertained, as the place of attack was unknown. In the sub-districts which are supplied solely by the Southwark and Vauxhall Company, there were 200 deaths during the first four weeks of the epidemic, of which 171 had the supply of that company, and the rest had water direct from the river, or from pump-wells, or ditches.
In the next three weeks of the epidemic, from the 5th to the 26th of August, 18 deaths from cholera were registered in the sub-districts supplied by the Lambeth Company alone; of these 4 occurred in houses having the supply of that company, and the houses in which the others occurred were supplied from pump-wells or other sources. In the sub-districts in which the supply was intermixed, 518 of the fatal attacks of cholera occurred in these three weeks, of which I ascertained that 410 took place in houses having the supply of the Southwark and Vauxhall Company, and 80 in houses having the supply of the Lambeth Company, while the remaining 28 occurred in houses not supplied by either company, or of which the address was not known. During this period 644 fatal attacks occurred in the sub-districts supplied exclusively by the Southwark and Vauxhall Company, of which 567 happened to persons having the supply of the company, and the remaining 77 to persons obtaining water direct from the river, or from some other source.
It is to be regretted that we have not yet the exact number of houses supplied by each water company respectively, in those sub-districts in which the supply is intimately mixed up, as it is there that the investigation approaches completely to a crucial experiment. Dr. Farr has all the data for ascertaining this point, and I hope it will soon be worked out. In the mean time, however, we can arrive very nearly at the truth by the help of the Census tables. The entire number of inhabited houses in the sub-districts in which the water supply is intermixed was 44,686 at the time of the last census, and there were 3079 houses in the sub-districts which were supplied by the Lambeth Company to the exclusion of the other. These latter sub-districts, namely, Streatham, Norwood, Dulwich, and Sydenham, are chiefly supplied by private pump-wells, not more than one house in five at the utmost being supplied by the company; therefore, if we deduct one-fifth of the above from the entire number of houses which the Lambeth Company supplies, we shall have 25,491 as the number of houses which that company supplies out the 44,686 which were contained in the districts and sub-districts where the supply is intermixed; leaving 20,555 as the number supplied by the Southwark and Vauxhall Company. Some houses were built in a few of the less crowded sub-districts, between the time of the Census and the epidemic of 1854, but these are probably quite counterbalanced by a certain number of houses in Kennington and Brixton, which have a pump-well, and are not supplied by either company.
The 115 fatal attacks which occurred during the first four weeks of the epidemic in the 20,555 houses we have calculated to be supplied by the Southwark and Vauxhall Company, give 55 to every 10,000 houses, and the 14 fatal attacks which occurred in the 25,491 houses supplied by the Lambeth Company give 5 to each 10,000 houses; the cholera was therefore eleven times as fatal in the houses having one supply as the other. If we make a similar calculation with regard to the fatal attacks which occurred in the next three weeks in the sub-districts in which the water supply is intimately mixed, we find that the mortality of cholera was at the rate of 199 to each 10,000 houses supplied by the Southwark and Vauxhall Company, and 31 to each 10,000 houses supplied by the Lambeth Company. It was, therefore, between six and seven times as great during this period, to the population having one supply as to that having the other.
I will now state the results when the whole of the districts supplied by each of the companies are taken together, and compared with the entire number of houses supplied by each. In this way we get figures that are perfectly correct, and not merely a close approximation to the truth.
In the first four weeks of the epidemic there were 334 deaths from cholera in the districts to which the supply of the two water companies extends. Of these 286 were attacked while living in houses supplied by the Southwark and Vauxhall Company with water from the Thames at Battersea-fields, and only 14 in houses supplied with water from Thames Ditton. In 4 cases the houses were supplied with water from pump-wells, in 26 cases the water was drawn directly from the river or from ditches, and in 4 cases the supply could not be ascertained, as the place of attack was unknown. When the number of houses supplied by each of the companies respectively is taken into account, it is found that the cholera was 14 times as fatal in the houses receiving the water from Battersea-fields, and containing whatever might come down the sewers or over the side of a ship from cholera patients, as it was in the houses receiving the water from Thames Ditton.
I published the address of the houses in which the whole of the above 334 fatal attacks took place, appending the particulars of the water supply, and I have not heard that the correctness of the report has been called in question in a single instance.
The 286 cases occurring in the houses supplied with the water of the Southwark and Vauxhall Company were distributed over the whole area to which the water extends, reaching from Wandsworth to Rotherhithe inclusive; and this continued to be the case throughout the epidemic.
It is worthy of remark that while only 563 fatal cases of cholera occurred in the whole of this metropolis, containing over 300,000 houses, during the four weeks ending August 5th, 1854, 286, or more than one-half of the entire number, occurred in the 40,046 houses supplied by the Southwark and Vauxhall Company, while a great number of the remaining cases occurred in persons employed on the river, and drawing their drinking water from alongside the ship or barge. In the next three weeks of the epidemic, from the 5th to the 26th of August, 1180 deaths from cholera were registered in the districts of which I am treating. Of these fatal attacks, 977 took place in houses supplied with the water of the Southwark and Vauxhall Company, and 84 in houses supplied with the improved water of the Lambeth Company; there were 25 fatal attacks in houses supplied merely by pump-wells; in 76 cases, the water was obtained from the Thames, or from ditches, and in 18 cases the supply could not be ascertained, for the reason stated before.
When the number of houses supplied by each company respectively, is taken into account, it is found that in those three weeks, from the 5th to the 26th of August, the cholera was eight times as fatal in the houses supplied with water from Battersea-fields as in those supplied with the more pure water from Thames Ditton, the proportions being 241 fatal attacks in each 10,000 houses supplied with the former water, and 32 fatal cases in each 10,000 houses supplied with the latter.
An inquiry respecting the water supply in the house of attack, in all fatal eases of cholera, was made by the Registrar-General, through the district Registrars of all the south districts of London, beginning from the 26th of August, the day when my inquiry was left off. There were a considerable number of cases in which the supply could not be ascertained from the person registering the death, owing chiefly to the water-rates being "farmed," as the term is, but there is no reason to doubt that the returns were correct, so far as they went, and showed the same proportion as they would have shown if more complete. From the 26th of August to [33/34] the end of the epidemic, a period of ten weeks, 2443 cases were returned to the Registrar-General, in which the water supply in the house of fatal attack was that of the Southwark and Vauxhall Company, and 313 cases in which the supply was from the Lambeth Company; consequently, during this period, there were 610 fatal attacks in each 10,000 houses supplied by the former company, and 119 in each 10,000 houses supplied by the latter, and the malady was, therefore, more than five times as fatal to the population having water from the Thames at Battersea-fields, as to the population having the new supply, free from the sewage of London. (*In my inquiries, I made use of a chemical examination of the water in all cases where the other evidence was not quite conclusive. The Lambeth water contained rather less than a grain of common salt in each gallon, while the water of the Southwark and Vauxhall Company contained nearly forty grains. I ascertained afterwards from the information of Mr. Quick, the Engineer to the latter company, and from some examinations I made of the Thames water taken direct from the river, that the common salt was nearly all derived from a mixture of sea-water, owing to the extreme dryness of the season, which caused it to flow higher up the river than usual. When, Messrs. Graham, Miller, and Hofmann examined the water of the Southwark and Vauxhall Company, at the latter part of January, 1851, it contained rather less than two [33/34] grains of common salt. It has been objected (Brit. and Foreign Med. Rec., April, l855) that the water of the two companies might alter from day to day, and that I ought to have examined that in their reservoirs; but, besides that it would be impossible for the sea-salt to be elevated over Teddington Lock, and extremely improbable that the Thames in London should take on, in the middle of a dry autumn, the character it had in a wet winter, an examination of numerous specimens throughout the district is as good proof of the nature of the water supply as one made at the reservoirs. I am, however, able to say that the two kinds of water existed throughout the district during the whole time of my inquiries, and were characteristic of their respective sources, for I examined very numerous specimens where the other evidence was conclusive, independent of that derived from chemistry. The mere appearance of the water was generally enough to indicate its origin, but I never relied on that alone.)
It will be observed that, while the disproportion between the number of fatal attacks in the houses supplied respectively by the two kinds of water remained very striking to the last, yet that it somewhat diminished with the progress of the epidemic, being fourteen times as great in one class as in the other, during the first four weeks of the epidemic, eight times as great during the next three weeks, and more than five times as great during the last ten weeks. The reason of this is, that as the number of cases increased, the opportunities of taking the disease directly from the patient in the manner I first pointed out, increased also. The proportion of deaths in houses supplied by the Lambeth Water Company increased during the progress of the epidemic, just as it did in parts of London having a water supply which took no share in the propagation of cholera, as the central and north districts supplied by the New River Company.
The Registrar-General calculated from the Census returns the number of persons living in the houses supplied by the two water companies mentioned above; and by this means we are enabled to compare the mortality of these parts of the population with that of the rest of London, which is estimated according to the number of the people, and not of the houses. The mortality of London generally in the late epidemic was 44 to each 10,000 inhabitants; among the population supplied by the Southwark and Vauxhall Water Company it was 157 to each 10,000 inhabitants, while it was only 27 to each 10,000 persons having the supply of the Lambeth Water Company. The preponderance of deaths in the south districts over the other parts of London, was caused entirely by the mortality among the customers of the Southwark and Vauxhall Water Company; and it is extremely deserving of notice, that the customers of the Lambeth Water Company, although intimately mixed up with those of the former company, retained an immunity from cholera throughout the epidemic, not only greater than that of London at large, but greater than that of any of its divisions, except the central and north districts above alluded to, which are supplied by the New River Company with water receiving no town drainage whatever, and not even navigated by people living in boats. This circumstance confirms me in the conclusion which I expressed in a former paper to this Society, that the remarkable relation of an inverse nature, which Dr. Farr discovered to exist between the elevation of the soil, and the mortality of cholera in the metropolis, depended entirely on the relative purity or impurity of the water; taking into account not only the supply of the companies, but also that drawn from the Thames and tidal ditches, and that of the pump-wells, which are most liable, to pollution in the low-lying districts.
In the Report of the late General Board of Health on the Water Supply of the Metropolis, published in 1850, the following passage occurs, at page 130: "We could find no evidence to justify the supposition that the aggravated effects of cholera, in the lower districts, was to be attributed to persons drinking pipe-water, which, in fact, very few people do habitually drink." The latter part of this passage I found in my inquiries last year in the South Districts to be erroneous, for there were very few pumps in use, until one came to the more distant and suburban parts; in the more densely peopled parts of Lambeth, Southwark, and Bermondsey, the people seldom had any other water to drink than that of the cistern or water butt, and the mortality was greatest among children and others who drank it unboiled. As regards the influence of the pipe-water itself, I believe that, since the inquiries of last summer above alluded to, especially that part of them made and published by the Registrar-General, it has been generally admitted. In the recent Report of Dr. Sutherland, published by the present Board of Health, both the author himself, and every one of the Inspectors whom he quotes on the subject fully admit the influence of the impure water of the Southwark and Vauxhall Company on the prevalence and mortality of cholera, although they do not admit the explanation which I give of this influence. It only remains, therefore, for me to prove that this impure water can increase the prevalence and mortality of cholera in no other manner than that which I explained at the beginning of this paper, and I shall have established my point. I should first like to remark, however, that although a scarcity of water for such purposes as washing out dirty courts and alleys had often been complained of, I am not aware that the quality of the water supplied from any water-works had ever been suspected of actually promoting the prevalence of cholera, or any other epidemic disease, before I published my views on its pathology and mode of communication in August, 1849. So far was this from being suspected, that the most approved measure for preventing cholera in London was that of abolishing common privies and cesspools, in order to remove offensive odours, and by substituting water-closets, to send the evacuations of both the sick and healthy, as quickly as possible into the Thames, although it was well known that about half the metropolis were drinking the water of this river.
As far as I am aware, it is these views which have led to a knowledge of the injurious effect of water under certain conditions, and I would therefore suggest that they are worthy, on this account, of some amount of consideration from those who do not yet admit their entire truth. I would even suggest that this result of the views I entertain affords of itself a presumption that they are correct.
But to proceed to the proofs to which I alluded. There are very numerous facts to show that mere impurity in the water does not of itself increase the prevalence of cholera, even when that impurity consists of the contents of sewers and cesspools. The greater number of the shallow pump-wells of this metropolis contain a good deal of organic matter from the neighbouring sewers, house-drains, and cesspools, in fact, the ground being covered up with houses and pavement, they are chiefly fed from these sources, but they do not, as a general rule, take any share in the propagation of cholera during an epidemic; it is only here and there, when one of them happens to receive what comes from a cholera patient, that it communicates the malady to those drinking the water. Persons often allow the water in their cisterns and butts to become extremely foul and dirty, but this has no effect in promoting the disease, provided the water be originally of a kind, like that of the New River, which never contains anything proceeding from cholera patients.
It follows, therefore, that mere impurity in the water does not predispose to, or in any way increase the prevalence of, cholera; and that the disease, when influenced by the water, is really due to the specific cause of cholera contained in the water.
Those who dissent from the opinion, that the water promotes the prevalence and fatality of cholera, by containing the specific cause of the disease, generally believe that the ordinary impurities in the water act as what they call a predisposing cause. But a predisposing cause is one which is supposed to prepare the patient to be acted on by some more direct cause; and it must, therefore, require a certain time for its operation. But I met with many instances last summer of persons being fatally attacked with cholera in the south districts of London, very soon after arriving from a healthy part of the country, and drinking the water of the Southwark and Vauxhall Company. Some of them were attacked within forty-eight hours after their arrival. Many cases occurred also in the neighbourhood of Broad-street, Golden-square, last autumn, of persons who were not in the habit of drinking the water of the pump in that street, who yet were fatally attacked with cholera after taking the water contrary to their [34/35] usual position. I have notes of many such instances, but will mention only one, that of a family of three persons, at 51, Poland street, who were all attacked on the 1st of September, and died on the same day. They were not in the habit of drinking the water from this pump, but had a jugful on the evening of August 31. My informant was the brother of the deceased woman. He fetched the water on one of those evenings, and saw a sister who survives go for it on the other evening. There were several instances also of families and individuals who were in the constant habit of drinking it at the time of the great outbreak of cholera, escaped the malady. The above circumstances show that the water did not act as a predisposing cause, but must have contained the real and efficient cause of the cholera.
Anything which is supposed to act as a predisposing cause is generally believed to produce its effects by lowering the general health and reducing the strength; but observation shows that cholera attacks individuals of all kinds indiscriminately, when they are exposed to the influence of its specific morbid poison. We may ascertain, from a table constructed by Dr. Guy, that in 1849, some of the occupations which suffered more from cholera that any others were those in which the men are extremely strong and robust, and follow an out-door employment. The seamen and ballast-heavers suffered excessively; 1 in 24 of their whole calculated number died; whilst the coalporters and coalheavers suffered nearly as much, since 1 in 32 of their number died. In the last epidemic also, the men in these occupations suffered severely, but the numbers have not yet been calculated. The reason of those persons suffering so excessively from cholera is, that they draw the water they drink from alongside the ship, and, therefore, have a greater chance of getting the cholera poison in a fresh and unimpaired state, than when it has to pass through the reservoirs and pipes of a water company. It is quite evident to any one acquainted with these men, that the Thames water does not produce cachexia, or gradually undermine the strength.
Another circumstance, which shows very forcibly that the impure water produced its deleterious effects in time of cholera in no other way than by conveying the real material cause of the disease, is, that in the outbreaks caused by the contamination of a pump well, or other local supply of water, nearly all the cases occur together. The water in nearly all these outbreaks had been habitually contaminated for a length of time, and, if it acted as a mere auxiliary cause of cholera, it would increase the prevalence of the malady during the whole time of its existence in the town or neighbourhood, instead of which, without any chemical or physical alteration in the water, a sudden outbreak of cholera takes place among those drinking it; and in most of the instances, as in that at Surrey-buildings, Horseleydown, in 1849, and in that last summer in the neighbourhood of Golden-square, it has been found that the evacuations of a cholera patient were among the impurities which entered the water just before the outbreak. When the cholera is communicated through the medium of a large river, and the pipes of a water company, this sudden kind of outbreak, or increase of the disease, does not of course take place, but the disease gradually increases, as the number of fresh cases add fresh germs or particles of cholera poison to the water, and thereby increase the chances of a person getting one. The time when the epidemic begins to decline is usually that when, on account of a diminution of temperature, persons begin to leave off drinking unboiled water.
Another evidence of the way in which impure water must act in promoting cholera, is the fact itself of cholera being a communicable disease, as is proved by numbers of instances of overwhelming weight. For in itch, syphilis, small-pox, measles, and other communicable diseases, we do not look about for necessary or predisposing causes, but acknowledge in the reproductive morbid material of the disease its sole and sufficient cause. Any circumstance, therefore, which determines the attack of cholera may be presumed to do so by conveying the specific cause of the disease, especially where there is other evidence in favour of this event.
If this point is shown to be established, namely, that impure water increases the prevalence and fatality of cholera, by conveying the morbid poison from one patient to another, then the circumstance of the disease being communicated by swallowing the morbid poison with the food that has been touched with unwashed hands, or otherwise contaminated by the cholera evacuations, is also fully established; for it cannot be supposed that any poison, whether a morbid one or not, could produce active effects when mixed with an almost indefinite quantity of water, and not produce its effects also without the water. If the views I am explaining be correct, we have, therefore, the power of avoiding cholera as easily as one may avoid the itch. Every man may be his own quarantine officer, and go about during an epidemic among the sick almost as safely as if no epidemic were present.
In the recent Report on Cholera to the General Board of Health, by Dr. Sutherland, after saying--"It is believed by some that the water which induces cholera contains the specific poison of cholera in it," and that others consider the impure water only a predisposing cause, continues as follows: "The matter in dispute is really of no practical value, for if it be a fact that the use of impure water is injurious to the public health, the manner of its action is of very secondary importance, at least for practical purposes." P. 40.
It seems very curious that Dr. Sutherland should not have perceived that this question, as to whether or not the water contains the specific cause of cholera, involves the entire question of the cause and prevention of the malady, and also the approval or condemnation of nearly all the so-called sanitary measures which have been adopted with respect to cholera, since it was first expected in 1830. [84/85]
There are some remarks in Dr. Sutherland's report respecting the south districts of London which require to be noticed, because they refer to the subject of which I am treating, and also because some of them are not quite correct. Quoting from an unpublished report by Dr. Greenhow, Dr. Sutherland says: "After the epidemic of 1849, Christchurch parish was exclusively supplied with the new and comparatively pure water of the Lambeth Company, while St. Saviour's continues to be mainly supplied with the impure water of the Southwark and Vauxhall Company," Now this is an error; Christchurch parish is not entirely supplied with the Lambeth water, as there are some houses in every part of the parish supplied with the water of the Southwark and Vauxhall Company. There is no district or sub-district nearer than Streatham, Norwood, Dulwich, and Sydenham which is supplied exclusively by the Lambeth Company. This is important as regards Christchurch, because there was a very high mortality among the minority having the impure water, and a very low one among the majority having the water from Thames Ditton. St. Saviour's is not mainly but exclusively supplied with water by the Southwark and Vauxhall Company; this error is, however, of less importance than the other. Dr. Sutherland, continuing to speak for Dr. Greenhow, says: "During the late epidemic the mortality in St. Saviour's had advanced from 73 to 97 in 10,000, while the mortality of Christchurch had fallen from 100 in 10,000 to 44 in 10,000, of population." Striking as this difference in the numbers appears, it is much greater when it is known that a great proportion of the deaths in Christchurch occurred in the comparatively few houses having the impure water supply of the Southwark and Vauxhall Company. In the first four weeks of the epidemic there were three deaths from cholera in Christchurch parish, two of which occurred in houses supplied by the Southwark and Vauxhall Company, and one in a house supplied with the water of the Lambeth Company. In the next three weeks twenty-two deaths occurred; nine of the attacks took place in houses supplied by the Southwark and Vauxhall Company, twelve in houses supplied by the Lambeth Company, and one in a house where the inmates begged water all round, as the supply was cut off. Mr. Greenwood, the Registrar of Christchurch, also made an inquiry respecting these eases, and, on comparing our notes, we found that our results coincided respecting the water supply in every instance.
Dr. Sutherland continues as follows:--"This great difference is sufficiently striking; but, while admitting the beneficial results of the purer water, Dr. Greenhow considers it not to be entirely due to the water alone, for Christchurch parish has been improved in other respects of late years, by the covering over of a pestiferous ditch which formerly occasioned a great deal of atmospheric impurity in the neighbourhood, and by other sanitary measures."
Now, leaving out the fact that there are no open ditches in St. Saviour's, with its recent high mortality, if Dr. Greenhow had been aware that the small number of persons in Christchurch who received the impure water of the Southwark and Vauxhall Company suffered as high a mortality as a similar number in 1849, and that the population having the improved water were enjoying only the same amount of immunity as the inhabitants who had the same water in Lambeth Church, first part, amongst the bone-crushers and skin-dressers; or, the ragged, bare-footed people in the streets near the Cornwall-road, in the sub-district of Waterloo-road first part, he would have had no reason to suppose that the ditch had any share in propagating cholera in 1849. I believe that open ditches, which receive the dejections of cholera patients, do sometimes assist in the communication of that disorder, not only when people drink out of them, but also when children can get down to the edge, to pick out their marbles and other toys, and afterwards clean their hands with their tongues before showing themselves at home; but the above circumstances would seem to show that the ditch in Christchurch was not of either of these characters.
Dr. Sutherland proceeds, still quoting from Dr. Greenhow; he says:--"In proof that impure water, though a predisposing cause of cholera, does not act as a specific poison in producing cholera, Dr. Greenhow adduces several instances in which houses supplied by the Lambeth water suffered from cholera, while those supplied by the Southwark and Vauxhall water escaped."
These instances may be correct, notwithstanding Dr. Greenhow's mistake respecting the water supply of Christchurch and St. Saviour's; but I have to submit that the suffering or exemption from cholera in particular houses, whilst it bears on the question of the influence of the water, has no relation to the manner in which the influence is exerted. That is a question which must be decided by other means. The water of the Thames never became as full of the cholera poison as to affect persons in all the 40,000 houses supplied by the Southwark and Vauxhall Company, therefore the exemption of some of these houses was a matter of course; and, as the persons living in houses supplied with the Lambeth water were exposed to at least the same opportunities of taking cholera, as those living in the districts supplied with the New River water, and other water which could have no effect in propagating cholera, it was equally a matter of course that some cases should occur in houses supplied with water by the Lambeth Company. It must also be recollected that the people having this last-mentioned water were not prisoners in their houses. Mixed up as these houses are with others having the impure water of the Southwark and Vauxhall Company, it is not unreasonable to suppose that they would be liable to take the other water. Out of the very few fatal cases occurring in houses supplied with the Lambeth water, in the early part of the epidemic, one was that of a carman who was constantly going about, and took none of his meals at home except his supper, and another was a journeymen baker, who drank no water at home except in his tea, (of course boiled,) but he drank a great deal of cold water when at his work.
I have previously stated that, in the first four weeks of the epidemic, the fatal cases of cholera were fourteen times as numerous in a given number of houses supplied with the Vauxhall water, as in the same number supplied with the Lambeth water from Thames Ditton; and it is by no means improbable that out of every fourteen drinks of water taken at that time, one drink might be of a kind different from that supplied at the house of attack, to say nothing of the use of water for making and adulterating beverages which are vended.
I find from some further quotations which Dr. Sutherland makes, that I have the happiness of agreeing with Dr. Greenhow as to the effect of the impure water, though not as to its mode of action. Dr. Greenhow states that the use of the Southwark and Vauxhall water very greatly aggravated the pestilence; and further he says, "although, doubtless, the unwholesome water has much aggravated the result, it is only one cause among several." I believe no one ever supposed that impure water was the sole cause of cholera, and, for my part, I do not consider it a cause at all, but only a frequent medium or vehicle of the one true cause of the disease, namely, the reproductive cholera poison.
In speaking of sanitary improvements, Dr. Sutherland makes the following remark:--"Mr. Walsh states that Jacob's Island, Bermondsey and its immediate neighbourhood, suffered much less during the late epidemic, notwithstanding its greater severity, than it did during either of the two former visitations, which he says is attributable, without doubt, to the filling up of the foul tidal ditch, since the epidemic of 1849."
Judging from what Mr. Walsh stated on a former occasion in this Society, it is most likely that he would mention in his report the fact of a number of the inhabitants of Jacob's Island and the neighbourhood drinking the water of these ditches in 1849, but if so, Dr. Sutherland has not quoted this in his report; and as the quotation now stands, it would be understood by nearly every reader to imply that the aggravation of cholera in this neighborhood, in 1849, was caused by effluvia from the ditches; and that the improvement in l854 was due to improvement of the air, by the ditches being filled up. I have, however, the results of a statistical inquiry to show that such was not the case. The Metropolitan Commissioners of Sewers caused an inquiry to be made, at the close of the epidemic of 1849, into the effects of using the water of these ditches; and Mr. John Grant, the Assistant Surveyor to the Commissioners for Kent and Surrey, was kind enough to favour me with the result. In Jacob's Island, and the streets immediately surrounding the ditches, there were 7286 inhabitants. Of these there were 865 individuals having no other supply of water than the ditches, and the remaining 6421 had the supply of the Southwark and Vauxhall Watar Company, or were supplied by private pumps. During the first nine months of 1849, 18 deaths took place from cholera, [85/86] and 8 deaths from other causes, amongst the 865 persons having no water supply but that of the ditches; and 95 deaths from cholera, and 46 from other causes, amongst the 6421 persons having another supply. The mortality from cholera was, consequently, at the rate of 208 in 10,000 amongst the persons using the ditch water, and 147 in 10,000 amongst the inhabitants who had the supply of the Southwark and Vauxhall Company, or that of private pumps. The mortality of the population living amongst and around the ditches, but not drinking the water, was, in fact, almost exactly the same as that of the other inhabitants further removed from the ditches; whilst that of the people who were obliged to drink the water was more than one-third higher; as the following figures from the Report of the Registrar-General show. St. James's, Bermondsey, in which Jacob's Island is situated, suffered a mortality from cholera of 142 in 10,000, St. Mary Magdalen, Bermondsey, a mortality of 159 in 10,000, and the Leather Market sub-district of Bermondsey a mortality of 160 in 10,000.
The ditches were of considerable extent, and as wide as an ordinary canal. The water had been formerly used for turning the wheel of a mill, as it flowed back into the river, but of late years the ditches were usually kept full, and only emptied at intervals. During the time of my visits in August and September, 1849, when the cholera was at the worst, they were not emptied at all, and no mud was exposed. The water of the Thames, admitted into these ditches, received the sewage of the surrounding population, either directly, by the privies overhanging the ditches, or through channels and drains. Thames water emits no smell, although the odour of exposed mud, and that from the mouths of sewers, sometimes leads persons to suppose it does.
The water of the ditches around Jacob's Island, although richer in manure than that of the Thames, did not seem offensive, so far as I could perceive; and if the ditches had been filled with black stinking mud, I believe they would not have increased the prevalence of cholera, as it could then have been impossible for the people to drink the water, and thus to imbibe the cholera poison coming from the cases in the neighbourhood. As it was, the water became moderately clear after standing in a vessel for a few hours, as the persons who were obliged to use it generally allowed it to do. Many of the persons having no other supply than that from the ditches, were able to beg water occasionally from their neighbours, otherwise the mortality amongst these people would probably have been still higher. In the recent epidemic, since the ditches were filled up, the mortality in the immediate neighbourhood has been only the same as that in the rest of the sub-district of St. James's, Bermondsey. The proportionate reduction of the mortality being entirely due, as the above facts prove, to the circumstance that none of the people drank worse water than those in the rest of the district. The whole of Bermondsey suffered a higher rate of mortality in 1854 than in 1849. This is the case with nearly all the other districts and sub-districts supplied exclusively by the Southwark and Vauxhall Water Company, and arises from the circumstance that, between 1849 and 1854, a great number of cesspools were suppressed, and water-closets substituted in their stead, throughout London, with the effect, when cholera was re-introduced, of sending the evacuations of the patients more generally and more quickly into the river.
Dr. Sutherland states that, "After the decline of the cholera, the President of the General Board of Health directed Dr. Fraser to make an inspection and inquiry into the condition of Lambeth-square, to ascertain to what extent the epidemic had prevailed among the population. This inquiry was directed in consequence of certain improvements in drainage having been carried out, subsequent to the epidemic of l849."--p. 67.
Dr. Fraser seems to have carried out his inquiry very ably and faithfully according to his instructions, which unfortunately contained no intimation that the supply of water had been altered in any part of Lambeth, and he appears not to have been himself aware of the circumstance, or he would have alluded to it. Lambeth-square contains 35 eight-roomed houses, inhabited by the better class of artisans. There were six deaths from cholera in 1849. In 1852 water-closets were substituted for open privies, and improvements were made in the drainage, and last year there was no death from cholera. The general mortality has also been lower the last two years than during the two years previous to the alterations. An improvement took place in 1852, however, of which Dr. Fraser was not aware. Lambeth-square is the property of one person, and is entirely supplied with water by the Lambeth Water Company, who in that year removed their source of supply from the middle of the sewers of London to Thames Ditton, as was before explained. To show that this was the real cause of the late immunity from cholera, I shall allude to another property, which has all the advantages described by Dr. Fraser as belonging to Lambeth-square, and the additional one of not being surrounded with the offensive smells external to the property, of which the inhabitants of that square still complain; but which has a water supply very similar to that which Lambeth-square had in 1849, namely, the supply of the Southwark and Vauxhall Company. In the Weekly Return of Deaths for September 9, 1854, the Registrar of the Clapham district writes as follows:--
"In consequence of there being a larger number of deaths from cholera this week in the vicinity of Park-road than in any other part of my district, I have inspected Park-crescent and Crescent-road, and found the drainage very good; the houses have recently been built, and there is great credit due to the landlords for the care they have taken to render them in every way comfortable and healthy; there is a water-closet and water laid on to each of them; but when I examined the water I found it in such a filthy state that I advised the inhabitants not to drink any more of it for the present. At most of the houses they had pieces of flannel, two or three thick, to act as filters."
There were only 472 deaths last year in all the 26,107 houses supplied by the Lambeth Water Company, or 1 death to each 56 houses, and therefore it is not surprising that a group of 35 should have escaped having a death.
Dr. Sutherland quotes some remarks respecting the water supplied to different parts of London, by Dr. Hassell, who very truly observes that the most impure is that of the Southwark and Vauxhall Company. He says: "Between it and the water of the Thames, as taken from the river at the spot at which the Southwark and Vauxhall Company obtains its supplies, there is frequently only that amount of difference which would arise from mere subsidence." Dr. Hassell describes the practice, which I have seen in hundreds of instances, of tying folds of flannel or other fabric over the taps through which the water of this company is distributed, and adds: "The quantity of dirt and organic matter obtained in this way in a short time is often perfectly surprising." Just after the above, on the same page (42), Dr. Sutherland quotes a passage from Dr. R. D. Thomson, who says that the water of the Chelsea Company is the most impure that is supplied in London, and that the water of the Southwark and Vauxhall Company comes next. The reader must not suppose, however, that the inhabitants of Belgrave-square and the great mansions round St. James's Park tie folds of flannel over the water taps, and collect a surprising quantity of dirt every time the water comes in, for this is certainly not the case. Dr. Thomson makes an unusual application of the word impurity, an application which would cause the water drunk at many of the fashionable watering places to rank as ten times more impure than that of an ordinary horse-pond. He includes every foreign ingredient in the water, in the term impurity, which may be allowable in a strictly chemical point of view, but practically pure water would, according to this view, be quite inadmissible in London, as it would dissolve the leaden cisterns and service-pipes, and poison the community.
The Chelsea Water Company obtain their supply from the same part of the river as the Southwark and Vauxhall Company, and their customers suffered a higher mortality from cholera in the late epidemic, than those of any other London water company, except the Southwark and Vauxhall. Between the mortality of the population supplied by these two companies, there was, however, a considerable difference. That of the population supplied by the Southwark and Vauxhall Company was 157 in each 10,000 inhabitants, that of the population an p plied by the Chelsea Company was 56, and that of the rest of London was 34 to each 10,000 inhabitants. The reason of the lower mortality in the districts supplied by the Chelsea Company than in those supplied by the Southwark and Vauxhall Company, can be very satisfactorily explained. While the latter company distribute the water nearly as they [86/87] take it from the Thames, the Chelsea Company have very large and expensive filtering beds, by which nearly all the visible dirt is separated from the water. The cholera poison may, much of it, be separated at the same time, but I have several reasons for concluding that the detention of the water reservoirs, which necessarily accompanies the filtration, is more effectual in diminishing the cholera poison than the mere filtration itself.
Whilst the Chelsea Water Company were detaining their water in large open reservoirs, during the hot dry weather of last summer, in order to separate from it as much as possible of what comes down the sewers, it was evaporating, and the relative quantity of sea salt, and of the salts belonging to the water of the river, were necessarily increased; in this way, Dr. Thomson, according to his method of investigating impurity, was able to pronounce this water more impure than that of the Southwark and Vauxhall Company.
Dr. Sutherland quotes a passage from Dr. Thomson, which seems to throw a very unmerited blame on the water of the New River Company. It is as follows:--"In the Soho district a very remarkable circumstance occurred in the houses supplied by the New River Company. In these it was found that the water, although taken on the same day, possessed a totally different composition from that contained in the reservoir at the New River Head; for, while the impurity of the reservoir water was 17.18 degrees, that of the Soho district, obtained from the New River Company, as ascertained by the water receipts, but from what source is unknown, was 30 degrees; the organic impurity being l.5l degrees in the first case, and 2 degrees in the second instance." P. 46.
Now, passing over the fact that the outbreak of cholera in this neighbourhood was confined, almost altogether, to persons who had water from a pump in Broad-street, Golden-square, and that those persons who confined themselves to the use of cistern water remained as free from cholera, throughout the outbreak, as persons in another part of London; there are two circumstances which ought at once to have shown Dr. Thomson that the water in these cisterns could have had nothing to do with the outbreak of cholera. The locality of this outbreak is extremely well defined. It is about a quarter of a mile in diameter, and includes a portion of the Golden-square sub-district, a portion of the Berwick-street sub-district, and a small part, only fifty yards wide, of the adjoining sub-district of St. Ann's, Soho. The outbreak commenced in all parts of the locality on the same day, and, as nearly as can be ascertained, at the same hour. But the New River water extends to only about one half of the locality attacked. It supplies the sub-districts of St. Ann's Soho and Berwick-street, but does not extend into the sub-district of Golden-square, which is entirely supplied with the water of the Grand Junction Company. The districts of these companies have been long fixed, as firmly as the parish boundaries, and there was small reason for the inspectors of the Board of Health to examine the receipts. But, even if the New River Company had supplied all the locality of the outbreak, there is another circumstance which might have shown Dr. Thomson that this water could have no connexion with it. It would be impossible that the company's pipe, after proceeding a certain distance down Wardour-street, should suddenly take up a certain quantity of additional foreign matter or impurity; and that, after proceeding some way, it should as suddenly leave off this foreign matter again, just where the cholera ceased, and that these two processes should take place in nearly all the streets of the locality. A little inquiry also would have shown Dr. Thomson that the kind of water he speaks of extended far beyond the limits of the outbreak. The reason of its differing from that at the New River Head admits of a very easy explanation, but I am treating of cholera, and not of water supply.
Mr. Glover, in his Report on the Common and Model Lodging Houses, recently published, in speaking of the Soho Chambers, 36, Old Compton Street, makes the following remark:--"In the district of Golden-square (in which these chambers are situated), up to October 7th, no less than 267 persons died from cholera alone, exclusive of the mortality from diarrhœa; and yet in these chambers there was not a single case of cholera, and only seven of diarrhœa, none of which proved fatal.* (*Page 27.) Mr. Glover moreover enumerates Compton-street among those in which "the inhabitants were a dying in large numbers daily. "Now, in the first place, Old Compton-street, in which the Soho Chambers are situated, is not in the district of Golden-square, but in the next district but one to it; namely, in the district of St Ann's Soho, the district of Berwick-street lying between the two. In the next place, and what is of still more importance, so far from Compton-street being one of the streets in which the inhabitants were dying in large numbers daily, there was not a single death from cholera in this street, either during the outbreak or for three weeks before or after it. The outbreak extended to a small part of the parish of St. Ann's, Soho, but not into Compton-street, than which there was not a street more free from cholera in London. It is a street containing 53 large houses, nearly all of them divided into tenements, and densely inhabited. The population of this street is probably not less than a thousand persons, and yet not a death from cholera was registered from it, from August 19th to September 30th, inclusive.
Mr. Glover makes it appear that the mortality of cholera in the common and model lodging-houses, during the late epidemic, was only at the rate of 7 to 10,000 inhabitants, whilst in the metropolis generally the mortality was 44 to 10,000. It is but justice to Mr. Glover to state that he makes the following remarks:--"This result is of so startling a character, that some doubts naturally arise as to whether the police return can be taken as actually correct, or merely as an approximation to the actual amount of mortality. It is very probable that many cases originated in the houses which ended fatally elsewhere."--P. 10.
The following circumstances, with which I became acquainted in making an inquiry for a different purpose, prove that Mr. Glover's surmise is correct. During the first seven weeks of the late epidemic there were only six deaths from cholera registered from the common lodging-houses in the parish of St. George, Southwark; but during this period there were seven deaths in the workhouse of persons who were admitted from the common lodging-houses, after being attacked with cholera. In fact, out of thirteen persons admitted into the workhouse, during these seven weeks, with fatal attacks of cholera, seven of them came from the common lodging-houses, as I have stated, and only six from all the other places, including two whose address was unknown, and who might also have been persons who generally lived in these lodging-houses. It is very probable, therefore, that if Mr. Glover had searched the books of all the workhouses and hospitals in London he would have been able to get a much nearer approximation to the real number of fatal attacks of cholera occurring in the common and model lodging-houses than he has done.
Except the distribution of the cholera poison in the water, there is no circumstance which favours its propagation so much as the crowding together of people of uncleanly habits; it is, therefore, very probable that the regulation of the common lodging-houses, and especially the establishment of model ones, has contributed greatly to the mitigation of the recent epidemics; but it is not likely that the inmates of the lodging-houses have enjoyed an immunity from cholera so much exceeding that of the inhabitants of May Fair as was indicated in Mr. Glover's report. As for the entire escape of model lodging-houses whilst the cholera was raging around, which has been so much commented on in the public prints, it did not exist at all. The idea arose out of the error respecting the Soho Chambers, which I have pointed out above.
The only other subject to which I shall allude in connexion with the recent Reports of the Board of Health, is the statement, several times repeated, and implied almost everywhere, that the cholera has been most severe where the air was most impure. That there is an occasional association between cholera and impure air, is what might be expected, according to any view of the pathology of cholera, but that this amounts to anything like a rule, a very few examples, drawn from the last epidemic in London, will serve to prove to every one acquainted with this metropolis. The sub-district of Saffron-hill, with the open Fleet Ditch steaming through it has experienced a lower mortality from cholera in the recent epidemic than any other sub-district in London, except the neighbouring one of St. George the Martyr, Holborn. Saffron-hill had a mortality of 5, and St. George of 4, in 10,000. No one acquainted with the south districts of London would assert that the air at Clapham and Kennington is as impure as in the low-lying districts of Lambeth, crowded with a poor [87/88] population, and containing the bone-boilers, and other offensive trades; yet the following figures, from the reports of the Registrar-General, show how these respective sub-districts were visited by cholera. I have added the London-road sub-district of Southwark, as it contains a very poor population in very dirty streets, and is on a level with Trinity high-water mark.
The reason of the lower mortality in the last four sub-districts, is that they receive a good deal of the new water supply of the Lambeth Company, while Clapham and Kennington 1st Part are chiefly supplied by the Southwark and Vauxhall Company, where the people have not pump-wells. In Kennington 2nd Part the water of the two companies is pretty equally distributed.
Cholera, as I stated before, spreads more readily from person to person in the crowded dwellings of the poor than under other circumstances. Even when the malady is propagated through the water supply, it causes a higher mortality among the poor than among the well-to-do, because, in addition to the cases caused directly by the water, others arise from the disease passing from one member of a family to another. But the poor very generally live in places where the air is impure, therefore, a certain amount of association between cholera and impurity of the air might be expected. A far greater association of this kind than actually exists, would, however, be no proof of any connexion in cause and effect. If an inquiry were set on foot with regard to the itch in London, and other towns, it would be rarely met with except in situations where the air is impure; a far greater association would be found between impure air and itch, than between impure air and cholera, and yet we know that impure air has no share in causing the itch.
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