STRUCTUEE,DEVELOPMEXT,AND BIONOMICS OP HOUSE-PLY. 391 
infantry, and he shows how this affects the incidence of enteric 
fever. In the British Army in India, 1902-05, the ratios per 
1000 per annum of cases admitted were : cavalry 41‘1, and 
infantry 15'5 ; and in the U.S. Army were : cavalry 5'74, 
and infantry 4’75. He states that : A study of the incidence 
of enteric fever shows that stations where there are no filth 
trenches, or where they are a considerable distance from the 
barracks, all have an admission-rate below the average, and 
all but one less than half the average.” 
All these facts are equally applicable to the conditions in our 
own towns and cities. Where the old conservancy methods are 
used, such as pails and privy middens, the incidence of typhoid 
fever is greater than in those places where the system of water 
disposal has been adopted. I have examined the annual 
reports of the medical officers of health of several large towns 
where such conversions are being made, and they show a 
falling-off of the typhoid fever-rate coincident with this 
change. In Nottingham, for example,^ in the ten years 1887- 
1896, there was one case of typhoid fever for every 120 houses 
that had pail-closets, one case for every 37 houses with privy 
middens, and one case for every 558 houses with water-closets. 
'Phe last were scattered, and not confined to the prosperous 
districts of the town. 
One of the most important investigations on the relation 
of flies to intestinal disease was that of Jackson (1907). 
He investigated the sanitary condition of New York 
harbour and found that in many places sewer outfalls had not 
been carried below low-water mark, consequently solid matter 
from the sewers was exposed on the shores, and that during 
the summer months on and near the majority of the docks 
in the city a large amount of human excreta was deposited. 
This was found to be covered with flies. The report, consi- 
dered as a mere catalogue, is a most severe indictment against 
the insanitary condition of this great water front. By means 
of spot-maps he shows that the cases of typhoid are thickest 
‘ ‘‘Typhoid Fever and the Pail System at Nottingham,” ‘Lancet,’ 
November ‘29tli, 1902, p. 1489. 
VOL. 54, PART 3. — NEW SERIES. 
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