CHAPTER IV 



THE TRANSFORMATION OF ENDOPLASM INTO 

 ECTOPLASM 



Perhaps none of the factors influencing the streaming of the 

 endoplasm mentioned above exercises as profound and constant 

 an influence as its capacity to form ectoplasm. As has been in- 

 timated earlier (p. 3-9) streaming as observed during locomotion 

 is not supposed to be possible at all unless accompanied by the 

 formation of ectoplasm at the forward ends of pseudopods, and 

 its transformation into endoplasm at the posterior end of the 

 ameba. We may therefore next consider the role ectoplasm plays 

 in locomotion, and in some other fundamental activities of the 

 ameba. 



In the first place it is necessary to define the word ectoplasm, 

 for two entirely different meanings are sometimes given to it. 

 It is used often to designate the clear non-granular layer of pro- 

 toplasm which thinly covers some of the commoner amebas, and 

 is especially prominent in some of the small species, where the 

 larger part of the anterior end often consists of protoplasm quite 

 free from granules. The other use to which the word is put is 

 to designate the layer of protoplasm on or near the outside of the 

 ameba which is more or less rigid and motionless, resembling the 

 gel state of a colloid. It is the latter meaning that is given the 

 word as used in this discussion, while I shall follow Jennings 

 ('04) and other, earlier, writers in using the word hyaloplasm in 

 speaking of the outer clear layer. It may be necessary to add 

 that neither of these two words is strictly definable, for in some 

 cases, at least, hyaloplasm is not more rigid than the endoplasm, 

 while in other cases it is. Strictness of definition can, of course, 

 come only as investigation proceeds; and these words as well as 

 the word endoplasm, should not be taken as defining the proper- 

 ties of the substances to which they refer, but only as labels. 



The demonstration of the most conspicuous and important prop- 

 erty of ectoplasm in Amoeba proteus is easily made. With the 



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