12 NEW YORK STATE MUSEUM 



execution of this direction by a favorite nurse. It is well known 

 that soil infected by these germs may be the origin of new cases, 

 and Dr Veeder significantly observes that the annual recurrence of 

 typhoid fever in the above noticed locality ceased with the death 

 of the two parties mentioned above and a change in the method of 

 disposing of typhoid discharges. The germs producing other in- 

 testinal disorders are discharged from the system, though pre- 

 sumably not persisting for such extended periods. It is well known 

 that the bacilli causing tuberculosis are abundant in the sputum of 

 patients and are therefore, under the prevalent sanitary conditions, 

 easily accessible to flies. 



The house fly subsists entirely upon fluids and feeds with appar- 

 ently equal gusto upon fresh manure, decaying vegetable matter, 

 sputum or the daintiest culinary preparations. It is only neces- 

 sary for discharges from patients suffering from typhoid fever or 

 other intestinal diseases to be exposed in open vessels, poorly con- 

 structed privies, or even in vacant lots near dwellings in order to 

 secure the spread of the infection. The hairy legs are fouled with 

 thousands of deadly bacilli and countless numbers are swallowed. 

 Shortly thereafter the flies may appear in the house and incidentally 

 contaminate the food, to the great peril of the consumer, with the 

 germs adhering to the limbs and those deposited with undiminished 

 virulence in the familiar fly specks. This, while disgusting and 

 abhorrent to every sense of decency, occurs repeatedly and is 

 apparently ignored by the masses, despite the deadly peril thus in- 

 curred. One fly, after having fed upon contaminated matter, may 

 carry many more bacilli than usually occur in gallons of infected 

 milk or water. 



Habits. The house fly breeds by preference in horse manure, 

 though it lives to a limited extent in cow manure and miscellane- 

 ous collections of filth, especially decaying vegetable matter. The 

 flies deposit their eggs upon manure and similar material, the 

 n^aggots hatch in less than 24 hours and, under favorable condi- 

 tions, complete their growth in 5 to 7 days. The white conical 

 maggots some half an inch long then transform to an oval, brown, 

 resting or pupal stage, remaining in this condition from 5 to 7 days. 

 The life cycle is therefore completed in 10 to 14 days, the shorter 

 period being true of the warmer parts of the year, particularly in 

 the vicinity of Washington, D. C. One fly may deposit 120 eggs, 

 and as there may be 10 or 12 generations in a season, it is not sur- 



