On the mode of communication of cholera

by John Snow

“In London a remarkable change was observed in the proportion of the sexes affected in the course of the epidemic. In four weeks of October 1848, the deaths of 80 males and of 42 females by cholera were registered; in the thirteen last weeks of the year the deaths of 258 males and 210 females were registered; and there was an excess of males at all ages, but particularly in the ten years of age 15–25. In the quarter ending March 1849, the deaths of males amounted to 250, of females to 266: at the age of 25 and upwards the excess of deaths among females was considerable. In June, at the commencement of the great outbreak, the males again furnished the most numerous victims. At the close of July the females died in greater numbers than the males, and continued to do so to the end. In the week that the mortality was highest, the deaths of 895 males and of 1131 females were returned. In the September quarter the deaths of males under the age of 25 exceeded the deaths of females; but after that age the proportions were reversed.”

PROPORTION OF THE SEXES WHO DIE OF CHOLERA.

The greater part of the female population remain almost constantly at home, and take their meals at home, whilst a considerable number of the men move about in following their occupations, and take both food and drink at a variety of places; consequently, in the early part of an epidemic, when the disease only exists in a few spots, the male part of the population is most liable to come within the operation of the morbid poison; but at a later period of the epidemic, when the cholera is more generally diffused, it may reach those who stay at home as readily as those who move about; and in addition to the risk which the women share with the men, they have the additional one of being engaged in attending on the sick.

It is a confirmation of this view of the matter that, when the cholera poison is distributed through the pipes of a Water Company, the above rule does not hold good, but a contrary one prevails, owing, probably, to females being less in the habit of drinking beer than men, and being therefore more likely to drink water. Of the 334 deaths detailed in the Appendix to this work (286 of them amongst the customers of the Southwark and Vauxhall Water Company), only 147 were males, whilst 187 were females. The deaths occurred in the first four weeks of the recent epidemic. On the other hand, out of the 229 deaths from cholera which occurred in all the rest of London during this period, 140 were males and only 89 females. When the mortality of the whole of the metropolis during this period is taken together, there is a slight preponderance on the part of the males; the numbers being,—males 287, females 276: total 563.

The deaths from cholera in England in 1849 were 53,293; of those, 14,718, or 27 per cent. of the whole, occurred in children under 15 years of age. Of the 334 deaths which are recorded in the Appendix to this work, 127, or 38 per cent., are those of children under 15, whilst of the remaining 229 which occurred in the rest of London during the first four weeks of the epidemic, only 61, or 26 per cent., took place before the age of 15,—a proportion nearly the same as in the whole of England in 1849. The higher proportion of deaths amongst children in the houses supplied with the impure water from the Thames at Battersea Fields, probably arose from the circumstance that children are very fond of drinking water in warm weather. I often heard such remarks as the following, in making my inquiries in the south districts of London:—“My children like water better than tea or anything else, I cannot keep them away from the water-butt;” or, “the child that is dead used to drink a great deal of that water, she was big enough to reach to the butt herself.”

Dr. Guy, physician to King’s College Hospital, made a table showing the occupations of 4,312 males, of fifteen years of age and upwards, who died of cholera in London in the epidemic of 1848–49; together with the ratio which the deaths bear to the living, as well as it could be ascertained from the census of 1841. I have not room for the whole table, but have selected the occupations which suffered most, and those which suffered least. The following abstract of Dr. Guy’s table contains all the occupations where the deaths from cholera equalled one-fiftieth of the number living, and all those in which the deaths did not exceed one in two hundred and fifty living.

PROPORTION OF DEATHS IN DIFFERENT OCCUPATIONS.

In some of the occupations which show a high relative mortality, the number of living is too small to allow of any reliable statistical result, and the relative mortality is probably due to accidental circumstances quite unconnected with the occupation. In other cases, however, the numbers are so considerable as to indicate something more than accident. The 299 sailors, for instance, constituted one twenty-fourth of the whole estimated number in that occupation. The 7 ballast-heavers form just the same proportion of the whole in that occupation, and the 53 coalporters and coalheavers constituted one in 32 of those so employed. Now all those persons lived or were employed on the river, where it is the habit to drink water drawn by pailfuls from the side of the ship. The 67 hawkers are one in 22 of the whole number. These persons are constantly moving about, and are in the habit of living in crowded lodging-houses, and consequently must be extremely liable to contract any communicable disease. Tanners nearly all live in Bermondsey and Lambeth, supplied in 1849 with none but very impure water, as was previously explained. The weavers probably suffered the high rate of mortality from the crowding of their apartments in Spitalfields, and the uncleanness of their habits.

The persons who suffered less from cholera than any other part of the male population, are footmen and men-servants; and it is impossible to conceive a class less exposed to the disease. They live in the best parts of London, and go from home much less than their masters. The low rate of mortality amongst medical men and undertakers is worthy of notice. If cholera were propagated by effluvia given off from the patient, or the dead body, as used to be the opinion of those who believed in its communicability; or, if it depended on effluvia lurking about what are by others called infected localities, in either case medical men and undertakers would be peculiarly liable to the disease; but, according to the principles explained in this treatise, there is no reason why these callings should particularly expose persons to the malady.

TABLE XIV.