



^^ r-* 



* 





: . 





- 



D 



Fig. 28. 



Protoplasm of different cells, showing foam structures. A Pseudopod of a marine 

 rhizopod. The protoplasm only shows foam structure at the point of stimu- 

 lation. B Epidermic cell of lumbricus. C Nerve fiber. D Part of the cell 

 body of a ganglia cell. (A-C after Butschli, D after Held.) 



