Unicellular Organisms Like Pluricellular 59 



protoplasm to this new formation requires just as long 

 as the posterior end remote from the adoral zone. 32 



This impulse to reorganization which enables proto- 

 plasmic substance already organized to take on any other 

 organization whatever speaks strongly in favor of the 

 hypothesis that it is due to a special formative energy 

 ("formgestaltenden Energie" as Nussbaum would call it) 

 emanating from the nucleus, which using the proto- 

 plasmic substance merely as a support or vehicle or as an 

 indifferent constructive material, would be in reality the 

 only quiddity which tends to dispose itself in that partic- 

 ular form, which constitutes for it the only possible 

 system in dynamic equilibrium. For the reasons above 

 stated we must think that this formative energy is prob- 

 ably nervous in nature. 



This ontogenetic function of the nucleus which we see 

 in unicellular organisms permits of very important deduc- 

 tions in relation to all organisms whatever. For the com- 

 plicated unicellular organisms whose manifold organs 

 have different and mutually independent functions, such 

 as for example a Stentor coereleus or a Paramoecium 

 caudatum, are not essentially different from pluricellular 

 organisms, but on the contrary are comparable with them 

 in all essential respects. 



"Between the internal differentiations of a complex 

 cell," says Delage, "and so between the body of certain 

 Infusoria, and the organs of the pluricellular being there 

 exists I think only a casual difference, which depends not 

 so much on the requirements of the differentiation as on 

 the size of the organism." 33 



82 Gruber : Uber kunstliche Teilung bei Infusorien. Zweite 

 Mitteilung. Biol. Centralbl., Bd. V. No. 5; May i. P. 138. 



3a Delage: L'heredite et les grands problemes de la biologic gen- 

 erale. P. 97. 



