194 THE STORY OF GERM LIFE. 



pendently of the artificial antitoxine, he does so 

 in part because he has developed the antitoxines 

 for counteracting the poison by his own powers. 

 His cellular activities have, in other words, been 

 for a moment at least turned in the direction of 

 production of antitoxines. It is to be expected, 

 therefore, that after the recovery they will still 

 have this power, and so long as they possess it 

 the individual will have protection from a second 

 attack. When, however, the recovery results from 

 the artificial inoculation of antitoxine the body 

 cells have not actively produced antitoxine. The 

 neutralization of the poisons has been a passive 

 one, and after recovery the body cells are no 

 more engaged in producing antitoxine than be- 

 fore. The antitoxine which was inoculated is 

 soon eliminated by secretion, and the body is 

 left with practically the same liability to attack 

 as before. Its immunity is decidedly fleeting, 

 since it was dependent not upon any activity on 

 the part of the body, but upon an artificial inocu- 

 lation of a material which is rapidly eliminated 

 by secretion. 



CONCLUSION. 



It is hoped that the outline which has been 

 given of the bacterial life of Nature may serve to 

 give some adequate idea of these organisms and 

 correct the erroneous impressions in regard to 

 them which are widely prevalent. It will be seen 

 that, as our friends, bacteria play a vastly more 

 important part in Nature than they do as our 

 enemies. These plants are minute and extraor- 

 dinarily simple, but, nevertheless, there exists a 

 large number of different species. The number 



