vi PREFACE 



the protoplasm is restored to the condition of the fundamental 

 organization with a renewed potential of vitality, is treated as a 

 special attribute of Protozoa and as an important distinction 

 between Protozoa and Metazoa. Through such reorganizations 

 either by division alone as in the Zoomastigophora and in occa- 

 sional forms here and there throughout the Protozoa, or by the more 

 drastic means of endomixis and fertilization, the protoplasm is able 

 to continue at an optimum of vitality. With this conclusion and 

 with the recognition of an internal self-regulating mechanism for 

 reorganization, resulting in the continuation of vitality, we are in 

 accord with the essence of Weismann's conclusion that protoplasm 

 of Protozoa is potentially immortal. On the other hand, we can- 

 not agree with Weismann in his further conclusions that natural 

 death is unknown in Protozoa, and that every individual is a 



potential germ cell. 



G. X. C. 



New York City. 



