8 



NEW YORK STATE MUSEUM 



other intestinal disorders. It is more than probable that 

 flies play an important part in causing the heavy mortality among 

 bottle-fed babies, the proportion of deaths between these and 

 breast-fed babies being as 25 to i. It has been shown that flies 

 may ingest, carry and discharge tubercular bacilli, thus aiding 

 materially in spreading tuberculosis. Furthermore, it is held 

 that flies may, under certain conditions, convey plague, trachoma, 

 septicemia, erysipelas, leprosy, and there are reasons for thinking 

 that this insect may possibly be responsible for the more frequent 



F g. 1 Typhoid or house fly: a, male, seen from above; b, proboscis and palpus from 

 the side; c, tip of the antenna; d, head of female; e, puparium; f, the anterior breathing- 

 pore or spiracle, all enlarged. (After Howard & Marlatt, U. S. Dep't Agric. Div. Ent. 

 Bui. 4. n. s. 1896) 



new cases of smallpox occurring in the near vicinity of a hospital. 

 The eggs of certain intestinal parasites, such as those of the tape- 

 worm, may be swallowed by the fly and passed uninjured. 



Methods of carrying diseases. The most common and danger- 

 ous infections conveyed by the house fly are typhoid fever, other 

 intestinal disorders, including those affecting young children, and 

 tuberculosis. Typhoid germs may be discharged from the human 

 system several weeks before diagnosis is possible, continue in num- 

 bers 6 to 8 weeks after apparent recovery, and in exceptional cases 

 may persist during a period of several years. There are authentic 



