On the Mode of Communication of Cholera

Part 1

ON THE MODE OF COMMUNICATION OF CHOLERA.

JOHN SNOW, M.D.,

MEMBER OF THE ROYAL COLLEGE OF PHYSICIANS, FELLOW OF THE ROYAL MED. AND CHIR. SOCIETY, FELLOW AND VICE-PRESIDENT OF THE MEDICAL SOCIETY OF LONDON.

Second Edition, much Enlarged.

LONDON: JOHN CHURCHILL, NEW BURLINGTON STREET.

M.DCCC.LV.

LONDON:

T. RICHARDS, 37 GREAT QUEEN STREET.

PREFACE TO THE SECOND EDITION.

The first edition of this work, which was published in August 1849, was only a slender pamphlet. I have, since that time, written various papers on the same subject, which have been read at the Medical Societies, and published in the medical journals. The present edition contains the substance of all these articles, together with much new matter, the greater part of which is derived from my own recent inquiries.

I take this opportunity of expressing my thanks to the Registrar-General for the facilities afforded me in making these inquiries.

I feel every confidence that my present labours will receive the same kind consideration from the Medical Profession which has been accorded to my former endeavours to ascertain the causes of cholera.

Sackville Street, Piccadilly, 11 December, 1854.

CONTENTS.

PAGE

Outline of the history of cholera 1

Cases proving its communication from person to person 3

Cholera not communicated by means of effluvia 9

The pathology of cholera indicates the manner in which it is communicated 10

Analysis of the blood and evacuations in cholera 11 and 14

Cholera is propagated by the morbid poison entering the alimentary canal 15

Evidence of this mode of communication in the crowded habitations of the poor 17

—— amongst the mining population 19

Instances of the communication of cholera through the medium of polluted water, in Horsleydown 23

—— at Albion Terrace, Wandsworth Road 25

—— at Ilford and near Bath 32

—— at Newburn on the Tyne 33

—— at Cunnatore 35

Part 2

—— in the Black Sea Fleet 36

—— in the neighbourhood of Broad St., Golden Sq. 38

—— at Hampstead West End (the water being carried from Broad Street) 44

Explanation of the Map showing the situation of the deaths in and around Broad Street, Golden Square 45

Table of attacks and deaths near Golden Square 49

Outbreak of cholera at Deptford caused by polluted water 55

Communication of cholera by means of the water of rivers which receive the contents of the sewers 56

Influence of the water supply on the epidemic of 1832, in London 57

Table showing the mortality from cholera, and the water supply 58

Influence of the water supply on the epidemic of 1849, in London 60

Table showing this influence 62

Communication of cholera by Thames water in the autumn of 1848 66

New water supply of the Lambeth Company 68

Effect of this new supply in the epidemic of autumn 1853 69

Tables showing this effect 71 and 73

Intimate mixture of the water supply of the Lambeth with that of the Southwark and Vauxhall Company 74

Opportunity thus afforded of gaining conclusive evidence of the effect of the water supply on the mortality from cholera 75

Account of inquiry for obtaining this evidence 77

Result of the inquiry as regards the first four weeks of the epidemic of 1854 79

—— the first seven weeks of the same epidemic 82

Tables illustrating these results 84, 85

Inquiry of the Registrar-General respecting the effect of the water supply of the above-mentioned Companies during the later period of the epidemic 87

Comparison of the mortality of 1849 and 1854, in the districts supplied by the above-named Companies 89

Effect of the water supply on the mortality from cholera amongst the inmates of workhouses and prisons 91

Cholera in the district of the Chelsea Water Company 93

Effect of dry weather to increase the impurity of the Thames 95

Relation between the greater or less mortality from cholera in London and the less or greater elevation of the ground 97

This relation shown to depend on the difference of water supply at different elevations ib.

Part 3

Effect of water supply on the mortality of cholera in Birmingham, Leicester, etc. 98

—— in Exeter 99

—— in Hull 100

—— in York 101

—— in Dumfries, etc. 102

—— in Nottingham and Glasgow 103

—— in Paris and Newcastle-upon-Tyne 104

Limited inquiry respecting the effect of the water supply at Newcastle 107

Assent of the medical profession to the influence of polluted water on the mortality from cholera 109

True explanation of this influence 110

Answers to certain objections 111

Circumstances connected with the history of cholera explained by the principles advocated in this treatise, as,—

The duration of the epidemic in each place usually bears a direct relation to the number of the population 115

The effect of season on the prevalence of cholera 117

Proportion of the sexes who die of cholera at different periods of an epidemic, and under different circumstances 119

Proportion of deaths from cholera in certain occupations 121

Evidence that plague, yellow fever, dysentery, and typhoid fever are communicated in the same way as cholera 125

Instances in which ague was caused by impure water 129

Measures required for the prevention of cholera and other diseases which are communicated in the same way 133

Appendix, containing a list of the deaths from cholera which were registered in the four weeks ending 5th August 1854, together with the water supply of the houses in which the fatal attacks took place, in all the sub-districts to which the supply of either the Southwark and Vauxhall or the Lambeth Water Company extends 138

MAPS.

Map 1. Showing the deaths from cholera in Broad Street, Golden Square, and the neighbourhood, from 19th August to 30th September 1854. A black mark or bar for each death is placed in the situation of the house in which the fatal attack took place. The situation of the Broad Street Pump is also indicated, as well as that of all the surrounding Pumps to which the public had access.

Map 2. Showing the boundaries of the Registrar-General’s districts on the south side of the Thames in London, and also the water supply of those districts.

ON THE MODE OF COMMUNICATION OF CHOLERA.

The existence of Asiatic Cholera cannot be distinctly traced back further than the year 1769. Previous to that time the greater part of India was unknown to European medical men; and this is probably the reason why the history of cholera does not extend to a more remote period. It has been proved by various documents, quoted by Mr. Scot, that cholera was prevalent at Madras in the year above mentioned, and that it carried off many thousands of persons in the peninsula of India from that time to 1790. From this period we have very little account of the disease till 1814, although, of course, it might exist in many parts of Asia without coming under the notice of Europeans.

In June 1814, the cholera appeared with great severity in the 1st bat. 9th regt. N.I., on its march from Jaulnah to Trichinopoly; while another battalion, which accompanied it, did not suffer, although it had been exposed to exactly the same circumstances, with one exception. Mr. Cruikshanks, who attended the cases, made a report, which will be alluded to further on.

In 1817, the cholera prevailed with unusual virulence at several places in the Delta of the Ganges; and, as it had not been previously seen by the medical men practising in that part of India, it was thought by them to be a new disease. At this time the cholera began to spread to an extent not before known; and, in the course of seven years, it reached, eastward, to China and the Philippine Islands; southward, to the Mauritius and Bourbon; and to the north-west, as far as Persia and Turkey. Its approach towards our own country, after it entered Europe, was watched with more intense anxiety than its progress in other directions. It would occupy a long time to give an account of the progress of cholera over different parts of the world, with the devastation it has caused in some places, whilst it has passed lightly over others, or left them untouched; and unless this account could be accompanied with a description of the physical condition of the places, and the habits of the people, which I am unable to give, it would be of little use.

There are certain circumstances, however, connected with the progress of cholera, which may be stated in a general way. It travels along the great tracks of human intercourse, never going faster than people travel, and generally much more slowly. In extending to a fresh island or continent, it always appears first at a sea-port. It never attacks the crews of ships going from a country free from cholera, to one where the disease is prevailing, till they have entered a port, or had intercourse with the shore. Its exact progress from town to town cannot always be traced; but it has never appeared except where there has been ample opportunity for it to be conveyed by human intercourse.

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