PROTOZOAN GERM PLASM 



569 



equivalent in function to the aggregate of cells making up the metazoon, 

 and with some parts at least having the power to contract and move, 

 some to digest food, some to secrete, others to excrete and still others, 

 finally, to reproduce. Considered 

 in this sense the cell theory as ap- 

 plied to the Protozoa is obviously 

 inadequate. 



The especial portions of the 

 protoplasm that have to do with 

 these several different functions 

 of the protozoon can be identified 

 in many cases as structurally dif- 

 ferent from the remainder, espe- 

 cially those parts which have to 

 do with movement and with the 

 perpetuation of the race, i. e., the 

 germ plasm. In the majority of 

 Protozoa this portion of the 

 protozoon is clearly differentiated, 

 one time or another, from the re- 

 mainder of the cell, and this 

 justifies us in taking issue with 

 Weismann, and with the majority 

 of those who write casually about 

 the Protozoa, as having no so- 

 matic cell elements and there- 

 fore no possibility of natural 

 death. If it can be shown that 

 there is a specific germ plasm in 

 these unicellular animals, then 

 the matter of immortality differs 

 in no essential way from the 

 same problem in Metazoa or 

 Metaphyta where the germ cells 

 have a possibility of endless ex- 

 istence. The evidence points to 

 a common and universal law that 

 continued life is an attribute of an 

 especially endowed protoplasm, 



termed germ plasm, which forms the material basis of the reproductive 

 cells. 



The history of single Protozoa, if taken superficially, seems to point 

 to the fact that the protoplasm of these cells does not die a natural 

 death, but continues to live in successive generations of similar indi- 



VOL. LXXIX. —39. 



Pig. 1. 



Original. 



