PROTECTION. 



231 



tides of bioplasm which induced the first attack of 

 disease, bioplasts are produced, which continue to 

 give rise to others. As long as this production of new 

 germs by descent proceeds, the bioplasts must take 

 up pabulum, which other disease germs in their ab- 

 sence might appropriate. In this way we can account 

 for "protection" lasting only for a time. When 

 these germs cease to produce descendants, or, pro- 

 ducing descendants whose properties gradually 

 change, the state of "protection" ceases. Upon 

 the whole, then, I incline to the view that " protec- 

 tion" is due to the presence of bioplasts in the 

 blood, which have directly descended from those in- 

 troduced. These, growing and multiplying in the 

 blood, take up the pabulum suitable for the nutrition 

 of disease germs, and the growth and multiplication 

 of the latter and of germs allied to them in character 

 is prevented, should any such gain access to the 

 blood. 



While "protection" lasts, we may infer that 

 the growth and multiplication of the protecting 

 particles interferes with the growth and multiplication 

 of the virulent disease particles. After a time, how- 

 ever, the descendants of the first becoming exhausted, 

 the last may then be victors in the struggle for 

 existence. 



R 2 



