36 THE HOUSE FLY 



world, and in the degree that we seek for and apply know- 

 ledge in our everyday lives, so will we just in that degree 

 be able to roll back the tide of Nature's adverse forces. 



Careful observations have been made in America in 

 regard to flies and typhoid fever. It was found that when 

 a case occurred in a house, and where the family acted on 

 the physician's advice and exterminated the flies, and of 

 course also observed the ordinary precautions in regard to 

 the disinfection of the stools and urine, it was found that, 

 with very few exceptions, no other member of the house- 

 hold contracted the disease. On the contrary, in those 

 households where the same precautions were taken in 

 regard to disinfection, but where flies were not destroyed, 

 it was quite common to find that two or more members 

 of the household had contracted the disease. 



There is a very large mortality in South Africa from 

 dysentery and diarrhoea. The latter is not usually serious 

 when adults are affected, but is a very grave disease to 

 infants and is responsible for a considerable percentage of 

 deaths. The House Fly is largely responsible for epidemics 

 of these diseases. The effluvia given off by the frequent 

 evacuations of the patients attract swarms of flies, which 

 feed greedily on the infected excrement. So acute is the 

 fly's sense of smell that it can unerringly find the smallest 

 speck of injected matter, and if dry, it exudes a little fluid 

 from the end of its proboscis on to it, prior to sucking it up. 

 However careful a nurse may be in disinfecting the stools, 

 a great deal of infected matter is bound to escape observa- 

 tion, or is not reached by the antiseptics used. Should 

 flies be present, it is devoured, or a portion of it adheres to 

 the sticky hairs on the pads of the feet, and thus the virus 



