Statistics as to the incidence of disease in houses provided with water-closets and in houses with pail-closets or privies are somewhat confusing, but it is not going too far to say that water-closets appear to be in some cases more dangerous than conservancy systems.

The following words by Dr. Farr, the eminent statistician, are worth careful consideration:-"Almost coincidently with the first appearance of epidemic cholera, and with the striking increase of diarrhoea in England, was the introduction into general use of the water-closet system, which had the advantage of carrying night-soil out of the houses, but the incidental and not necessary disadvantage of discharging it into the rivers from which the water-supply was drawn." In London the mortality per 1,000 from diarrhoea was '215 in 1838, 201 in 1839, and 238 in 1840 and 1841, an average of '223. In 1849 connection of drains with sewers was compulsory, and the death-rate from diarrhoea became 1705 in 1849, '813 in 1850, 1.085 in 1851, and '983 in 1852, an average of 1.146, or five times the death-rate from 1838 to 1841. The average for the decade, 1871-80, was, according to Dr. Ogle, '940 per 1,000, or very little better than the rate for 1849 to 1852, and more than four times the rate for 1838-41. The number of deaths from diarrhoea in London for the ten years from 1871 to 1880 was 33,168.

If the death-rate of 1838-41 had been maintained during this period, the number of deaths would have been only 7,868. In other words, 25,300 lives appear to have been lost in London in 1871-80 from one class of disease alone, chiefly through mistaken "sanitation."

At Gainsborough, according to the report of Dr. Darra Mair, twenty-five of the houses invaded by fever during twenty months of 1897-8 were provided with privies, five houses invaded were provided with pail-closets, and sixteen with water-closets. As there were 2,455 houses with privies (either separately or in common), 305 with pail-closets, and 1,300 with water-closets, the incidence of the disease was as follows:-

It is not surprising to learn that "in some of the latter houses gross sanitary defects had been discovered in connection with the water-closets or the drains."

Recent statistics as to the incidence of enteric fever in other towns show that the experience of Gainsborough need not be repeated. Thus, Dr. Boobbyer, the medical officer of health for Nottingham, reported in 1897 that, during the ten years 1887-1896, the proportional incidence of this disease in Nottingham was as follows:-

There can be no doubt that in all midden-privies (and to a smaller extent in pail-closets) there is a risk of polluting the surrounding soil, and a certain amount of air-pollution cannot possibly be avoided.