308 



OUR BODIES AND HOW WE LIVE 



fondness for milk and its various products, which are 

 therefore liable to be polluted in many different ways. 1 



424. How Bacteria gain Access to the Body. The germs 

 of disease may gain access to our bodies in several different 

 ways. Thus, one kind of bacteria requires a break in the 

 skin in order to do harm. This mode of entrance to the 

 body is called inoculation. This may result from using 

 soiled instruments or tools, from gunshot injuries made 

 by broken glass or rusty nails, and from numerous other 

 causes. Death has resulted under certain conditions from 

 the scratch of a pin or even the prick of a penknife or the 

 point of a pair of scissors. 



Germs of disease may be carried by contact between 

 healthy and diseased persons. This is known as contagion. 



O Thus, the microscopic form 



ing ringworm is a familiar 

 example of germs which 

 have been carried by means 

 of a razor or a soiled towel, 

 or which come from han- 

 dling a stray cat infected 



1 It is not uncommon for a large 

 number of persons to be poisoned 

 from eating ice cream at some pub- 

 lic gathering. This is caused by a 

 change in the milk brought about 

 by the presence of bacteria. The 

 poisonous product of their action 

 called " tyrotoxicon " may also be 

 found in other foods which have 

 milk as their basis, such as cheese, 

 custard, and so on. There are vomiting and purging within a few hours 

 after eating the food, succeeded by great nervous prostration, from which 

 recovery follows slowly. 



FIG. 194. Different Kinds of 

 Milk Bacteria. 



