73 
dows and doors leading into kitchens, pantries and dining rooms. A 
single case of typhoid would start a severe local epidemic under such 
conditions.” 
Summer work in a bacteriological laboratory would convince anyone 
of the flies’ liking for pathologic material of any kind. They are sure to 
light near and crawl over slides being prepared for stains, which makes it 
necessary to cover everything with bell-jars to prevent laboratory infec- 
tion. Moreover, flies are always more attracted toward diseased persons 
than toward the healthy ones. 
The whole subject is of great interest to the sanitarian, because it opens 
up a comparatively new field in preventive medicine. It applies to the 
home as well as to the community in regard to general cleanliness and 
methods of garbage disposal. 
STRUCTURE OF HOUSE FLY. 
Any one who has examined the fly’s foot under the miscroscope can 
not fail to see how perfectly it is constructed for the retention of dirt and 
filth. The fine hairs and the suctorial discs afford magnificent opportuni- 
ties for infectious material to be lodged in and thus transported from one 
spot to another. In fact, in making a microscopical examination of several 
flies’ feet for the purpose of making a photograph, it was next to impossi- 
ble to find one that did not have considerable dirt attached to it. 
The proboscis of the fly also affords an excellent resting place for dirt 
of any kind, and the wings and body also serve to retain material. Thus 
the fly seems to be made for the purpose of carrying small quantities of 
dirt around with him all the time, a circumstance that is quite alarming 
if we could follow in the wake of the fly in his daily and hourly travels, 
instances of which have been cited above. 
LABORATORY WORK. 
While laboratory experiments are not always satisfactory in a subject 
of this kind, yet I take the liberty of describing here some that were 
undertaken in the Purdue laboratories during the past year. While the 
experiments, in part at least, have been done in other laboratories, the 
results obtained here were very satisfactory, and the plates were so well 
marked that I deem them well worth the attention of the Academy. 
