CHAPTER VII 

 THE FUSION OF INDIVIDUALS 



Important information concerning the regulation of 

 size, comparable to that obtained from the cutting 

 of individuals, might be obtained from the fusion of 

 individuals. No systematic studies of fusion have been 

 carried out; the possibility of fusing or transplanting 

 protoplasms has often been visualized, but the experi- 

 mental difficulties have proven deterring. Whereas 

 numerous means have been found of preventing the 

 separation of the progeny at the time of fission, the re- 

 uniting of progeny that have once separated is im- 

 mensely more difficult to control. 



1. Agamic Fusion 



But occasionally fusions of individuals occur with- 

 out any experimental manipulation. What are the re- 

 lationships existing between individuals, which gov- 

 ern their individuality and their power to reunite? 



Degrees of fusion. The union of cells without nu- 

 clear fusion was termed plastogamy by Hartog ('91). 

 It is convenient to distinguish "complete plastogamy", 

 in which fusion is so thorough as to form a doubly 

 endowed individual of normal form, from "pseudo- 

 podial plastogamy", in which the protoplasm is con- 

 tinuous, but separate bodily masses are preserved. 

 There are, also, unions of individuals with nuclear fu- 

 sion which are clearly not conjugations or gametic 

 unions or any other type of reorganizations. The ori- 

 gins of these fusions are very various and their persis- 

 tences show many gradations. 



The degree to which protista maintain their indi- 



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