4 THE HOUSE FLY 



each other on the lips and cause infection. Schoolboys 

 and girls suck pencils, pens, and use the mouth as a tem- 

 porary pocket for marbles and sundry other substances. 

 Others breathe through the mouth and get microbes into 

 their lungs, or swallow them into their stomachs. Unclean 

 mouths are favourite nursery grounds for microbes. The 

 scraps of food around the roots and between the teeth are 

 excellent breeding beds where many kinds of microbes 

 thrive, which in a few hours increase and amount to many 

 millions. To prevent this, the mouth should be cleansed 

 with a good dentifrice after each meal, and not a morsel of 

 food should be eaten at night after the final cleansing. It 

 is during the hours of sleep, when the salivary secretion is 

 inactive, that microbes breed without hindrance in the 

 mouth. 



The greatest ally of the disease microbe is the common 

 House Fly, which scientific men call Musca domestica. 

 The object of the preceding remarks was to pave the way 

 to a series of chapters on this dreaded House Fly, which is 

 the chief carrier of disease microbes, and the indirect cause 

 of most of the diseases in man and his domestic animals. If 

 a few score of venomous snakes accidentally escaped in a 

 town, there would be a profound sensation, and a sense of 

 insecurity of life would be ever present until they were 

 destroyed. Yet the presence of five hundred cobras scat- 

 tered throughout a city would be as nothing in comparison 

 to the awful, the appalling danger and risks incurred by the 

 presence of the common House Fly. 



