84 



and test ironi time to time, hy simply cultural methods,* whether or not the 

 bacteria are alive. Thus, in one experiment, there were mixed with human 

 serum typhoid fever germs in such numbers, that every drop of the serum 

 contained 50,000 bacteria. Two mimites later but 20.000 of these were 

 alive: at the end of ten juinutes. hut SOO ; and in twenty-five minutes, they 

 were all dead. 



Not only can serum kill bacteria, but most of the secretions of the 

 healthy human body are bacteria-killing: as well. Gastric jiiice, vaginal 

 secretion and nasal secretion, kill bacteria in enormous numbers. The hy- 

 gienic significance of this is evident from the fact that these bacteria-killing 

 substances, also, are moditied by modes of life. Dietary excesses may so 

 lower the bacteria-kiiliug properties of gastric juice, and unsanitarj- condi- 

 tions so lessen that of tlie tissue .iuices that susceptibility to infectious dis- 

 eases is gi'eatly increased. 



The third way of liygienic inii)ortance in which the body fights disease. 

 is by phagocytosis. In the body there are millions of white blood cor- 

 puscles, eacli having the power of independent motion and as one of its 

 functions the faculty of eating and destroying disease germs. 



It is found that the l^acteria-eating [tower of white corpuscles is largely 

 dependent upon certain chemical substancesy present in the blood and 

 tissue jiiices. ^\'ithout these chemical substances the eating of certain 

 pathogenic bacteria does not take place. With them, it is very active. It is 

 further found that these chemical substances are influenced by modes of 

 life. That they mny be increased or decreased under different hygienic 

 conditions. Phagocytosis, therefore, has also a place in popular hygienic 

 knowledge. 



One of the unfortunate results of the spread of knowledge of patho- 

 genic micro-organisms is the formation of an unreasoning popular fear of 

 disease germs. It is thought that a wide understanding of facts regarding 

 bodily resistance will tend to replace this unfortunate germ-fear by a 

 rational faith in the body's marvelous powers. That it may turn the tide 

 of hygienic endeavor, from an exclusive fight against bacteria to a com- 

 bined fight oiiaiiist bacteria and for Iwdily resistance. 



*See Popular Science Monthly, Vol. 66, pp. 474-177. 

 t Opsonins. 



