I III TYPHOID II. \ , OB HOUSE \'\.\ . - 7 
has ju>t been stated indicates that even under city conditions tin 
influence of this fly in the spread of this disease has been greatlj 
underestimated, li is not claimed thai under city conditions the 
house llv becomes by this argument a prime factor in the transfer 
of the disease, but it must obviously take a much higher relative 
rank among typhoid conveyers than it has hitherto assumed. Per 
haps even under city conditions it must assume third raid; -next to 
water and milk. 
It i- not alone as a carrier of typhoid that this fly is to be feared. 
In the same way it may carry nearly all the intestinal diseases. It 
is a prime agent in the spreading of summer dysentery, and in this 
way is unquestionably responsible for the death of many children 
in summer. One of the earliest accurate scientific studies of the 
agency of insects in the transfer of human disease was in regard to 
Hit'- as spreaders of cholera. The belief in this agency long pre- 
ceded its actual proof. Dr. (i. E. Nicholas, in the London Lancet. 
Volume II. 1873, page 724, is quoted by Xuttall as writing as follows 
regarding the cholera prevailing at Malta in L849: "My first im- 
pression of the possibility of the transfer of the disease by flies was 
derived from the observation of the manner in which these voracious 
creatures, present in great numbers, and having equal access to the 
dejection- and food of patients, gorged themselves indiscriminately 
and then disgorged themselves on the food and drinking utensils. 
In L850 the Superb, in common with the rest of the Mediterranean 
squadron, was at sea for nearly six months; during the greater part 
of the time she had cholera on board. On putting to sea, the flies 
were in great force: but after a time the flies gradually disappeared, 
and the epidemic slowly subsided. On going into Malta Harbor, 
but without communicating with the shore, the Hies returned in 
greater force, and the cholera also with increased violence. After 
more cruising at sea, the (lies disappeared gradually with the subsi- 
dence of the disease." 
Accurate scientific bacteriological observations by Tizzoni and 
Cattani in l ss <> showed definitely active cholera organisms in the 
dejecta of flies caught in the cholera wards in Bologna, Italy. These 
observations were subsequently verified and extended by Simonds, 
Offelmann, Macrae, and other.-. 
With tropical dysentery and other enteric diseases practically the 
same condition- exist. In ;i report by Daniel I). Jackson to the 
committee on pollution, of the Merchants' Association in New York, 
published in December. L907, the results of numerous observations 
upon the relation of Hie- to intestinal diseases are published, ami the 
relation of deaths from intestinal diseases in New York Citv to the 
