GENERAL PROPERTIES OF THE ECTOPLASM 



fertilization, remaining constant for the next thirty minutes 

 to drop again by more than lo per cent., remaining constant 

 as far as the eight-cell stage. Farther than this the obser- 

 vations were not carried. 



Rogers and Cole's figure gives the approximate rate of 



heat-production. In their words, "the greatest period 

 of heat-production occurs immediateh' upon fertiliza- 

 tion."^ This period falls in with that of the surface 

 changes described above. Say Rogers and Cole: "The 

 fact that the greatest heat-production by the egg comes 

 immediately after fertilization seems to us to make it plau- 

 sible to say that the entrance of the spermatozoon induces 

 a cortical oxidation-process, and that this process results in 

 the elevation of the fertilization-membrane." On the basis 

 of my observations and experiments, described above, these 

 findings of Rogers and Cole can be more precisely explained. 

 What they have measured is the heat liberated during the 

 disintegration of the ectoplasmic colloids. 



In addition to increased oxygen consumption and heat- 

 liberation other cellular processes can be related to these 

 surface changes in eggs. 



The wave-like process of break-down in the ectoplasm 

 by which the membrane is separated from the egg of Echhia- 

 rachnius described above, strikingly resembles the trans- 

 mission of change in various tissues. The nerve fibre may 

 be taken as an example because among animal cells it is the 

 most highly excitable and the most rapidly conducting. 

 As is well known, nerve when stimulated at one point trans- 

 mits this local effect throughout its course. As the propa- 

 gated effect, the nerve impulse travels along the stretch of 

 nerve, each point successively, beginning at that where the 

 stimulus was applied, becomes electro-negative to all other 

 regions of the nerve both behind and in advance of the 



^ Rogers and Cole, I.e. 



