28 NEW YORK STATE MUSEUM 
c Typhoid fever gradually disappeared in the fall of 1898, with 
the approach of cold weather, and the consequent disabling of 
the fly. 
It is possible for the fly to carry the typhoid bacillus in two 
ways. In the first place fecal matter containing the typhoid germ 
may adhere to the fly and be mechanically transported. In the 
second place, it is possible that the typhoid bacillus may be carried 
ir the digestive organs of the fly and may be deposited with its 
excrement. 
Dr Alice Hamilton in 1903, studying the part played by the 
house fly in a recent epidemic of typhoid fever in Chicago which 
could not be explained wholly by the water supply nor on the 
grounds of poverty or ignorance of the inhabitants, captured flies 
in undrained privies, on the fences of yards, on the walls of two 
houses and in the room of a typhoid patient and used them to 
inoculate 18 tubes, from five of which the typhoid bacillus was 
isolated. She further found that many discharges from typhoid 
patients were left exposed in privies or yards, and concluded that 
flles might be an important adjunct in the dissemination of this 
infection. More recently, Dr Daniel D. Jackson investigating in 
1907 the pollution of New York harbor, found that by far the 
eceater number of cases occurred within a few blocks of the water 
front, the outbreak being most severe in the immediate vicinity of 
sewer outlets. He gives a series of charts showing an almost exact 
coincidence between the abundance of house flies and the occur- 
rence of typhoid fever, when the dates are set back two months to 
correspond to the time at which the disease was contracted. The 
bacilli of typhoid fever were found by Ficker in the dejecta of 
house flies 23 days after feeding, while Hamer records the presence 
of this bacillus in flies during a period of two weeks. Most sig- 
riificant of all, it should be noted that competent physicians in 
position to make extended observations upon this disease and the 
methods by which it may become disseminated, are most strongly 
of the opinion that under certain conditions at least, the fly is a 
most important factor. Epidemics spread by flies, according to 
Dr Veeder, tend to follow the directions of prevailing warm winds. 
fe considers flies the chief medium of conveyance in villages and 
camps where shallow, open closets are used, thus affording the 
insects free access to infected material, and where it is possible to 
eliminate water and milk as the sources of infection. Drs Sedgwick 
and Winslow, writing in 1903 state that “the three great means 
