The Organism and its Protoplasm 133 



is applicable in the one case as in the other. He would have 

 no pseudo-scientific explanations, whether hidden behind 

 '^ Schlagworter'" or entities of the pure imagination, given 

 a semblance of objective reality by being connected with 

 actual objects. One of the great merits of Briicke's attitude 

 toward the problem of the constituents of the living beings 

 which lie beyond the reach of direct observation should be 

 specially pointed out, though this is not the place to speak 

 of it in detail. From several of his statements, but par- 

 ticularly from that about the analogies between the cell and 

 the smallest animals, we may infer that he had a genuine 

 appreciation of the distinction there is between the concep- 

 tion that there must be some sort of organization beyond 

 what the microscope reveals, and a conception of what the 

 specific nature of that organization is in particular cases. 

 So a critical examination of Briicke's fundamental essay 

 reveals the fact that though starting from a quite different 

 standpoint from that of Max Schultze it contains as little 

 as does Schultze's essay to support belief in the identity 

 of protoplasm in all living things. 



Results of Later Description and Classification of Cell 



Substances 



The question still to be considered is whether or not the 

 discoveries made since the pioneer era have furnished, by 

 the actual study of protoplasm, more support for the be- 

 lief in such identity. I do not believe any candidly critical 

 student will maintain that they have. On the contrary I 

 believe such a student will recognize that the indubitable 

 tendency of the evidence is toward the opposite conclusion ; 

 namely, that the protoplasm not only of all organisms, but 

 of many different parts of the same organism, is to some 

 extent different. 



That the observational knowledge of the substances con- 



