154 THE STORY OF GERM LIFE. 



through the skin to be discharged directly. The 

 battle between these phagocytes and the bacteria 

 goes on vigorously. If in the end the phagocytes 

 prove too strong for the invaders, the bacteria 

 are gradually all destroyed, and the attack is re- 

 pelled. Under these circumstances the individual 

 commonly knows nothing of the matter. This 

 conflict has taken place entirely without any con- 

 sciousness on his part, and he may not even know 

 that he has been exposed to the attack of the 

 bacteria. In other cases the bacteria prove too 

 strong for the phagocytes. They multiply too 

 rapidly, and sometimes they produce secretions 

 which actually drive the phagocytes away. Com- 

 monly, as already noticed, the corpuscles are at- 

 tracted to the point of invasion, but in some cases, 

 when a particularly deadly and vigorous species 

 of bacteria invades the body, the secretions pro- 

 duced by them are so powerful as actually to 

 drive the corpuscles away. Under these circum- 

 stances the invading hosts have a chance to mul- 

 tiply unimpeded, to distribute themselves over the 

 body, and the disease rapidly follows as the result 

 of their poisoning action on the body tissues. 



It is plain, then, that the human body is not 

 helpless in the presence of the bacteria of disease, 

 but that it is supplied with powerful resistant 

 forces. It must not be supposed, however, that 

 the outline of the action of these forces just given 

 is anything like a complete account of the matter; 

 nor must it be inferred that the resistance is in all 

 respects exactly as outlined. The subject has only 

 recently been an object of investigation, and we are 

 as yet in the dark in regard to many of the facts. 

 The future may require us to modify to some ex- 

 tent even the brief outline which has been given. 



