24 THE HOUSE FLY 



its way to the shelter of the nearest house. Settling itself 

 comfortably on the cheese, the corner of a slice of bread, on 

 an apple, a piece of cake, the rim of a cup, or some other 

 convenient situation, it proceeds to regurgitate, or in 

 other words vomit up a droplet of the filth it has recently 

 swallowed. This is carefully deposited on whatever the 

 fly is resting upon. Then the proboscis is protruded, and 

 the fly sucks it up again. A small portion, however, is left, 

 and this may contain many hundreds or thousands of 

 disease germs. On examination of a pane of glass in the 

 kitchen window it will be noticed that there are small stains 

 and larger ones. The former are fly specks or the excreta 

 of flies ; the latter are the regurgitated drops, or what is 

 left of them, after the fly has sucked them up. 



Repeated experiments have been made with a view to 

 ascertaining the number of specks and regurgitated drops 

 deposited by a fly within a given time. The following is an 

 instance. Ten flies were captured, and after being given 

 a feed of milk, were transferred to fresh clean cages. They 

 deposited in the form of specks and by regurgitation, 

 forty-one spots within the first hour ; sixteen in the second 

 and third ; twenty-four in the fourth ; twenty-four in the 

 fifth ; and fifty-nine in the interval between the sixth and 

 twenty-second hour. When flies are kept captive and food 

 placed in the cage, the spots were twice as abundant. Ten 

 flies could therefore soon smother the interior of a house 

 with disease germs. 



Through lack of knowledge we frequently do ourselves 

 and others grievous injury both morally and physically. 

 Every mother naturally desires her children to grow up 

 strong and healthy. Should one of them be unwell, her 



