344 



CELL-CHEMISTRY AND CELL-PHMSIOLOGY 



digest food, and the power of adhering to the substratum. Nearly 

 at the same time Verworn ('89) published the results of an extended 

 comparative investigation of various Protozoa that placed the whole 

 matter in a very clear light. His experiments, while fully confirming 

 the accounts of his predecessors in regard to regeneration, added 

 many extremely important and significant results. Non-nucleated 

 fragments both of Infusoria {e.g. Lachrymaria) and rhizopods {Poly- 





.■>■•■■-• 





"""% 



B 



\:V^-;-"^'^-;n-i.:VCr-V-".-. ; 7") 



\ •* .?''v -v.: : •^.V■.■■'-.•^;?:v■■.^ 





Fig. i6o. — Nucleated and non-nucleated fragments of Amoeba. [HOFER.] 

 A. B. An Amceba divided into nucleated and non-nucleated halves, five minutes after the opera- 

 tion. C. D. The two halves after eight days, each containing a contractile vacuole. 



stomella, Thalassicolla) not only live for a considerable period, but 

 perform perfectly normal and characteristic movements, show the 

 same susceptibility to stimulus, and have the same power of ingulf- 

 ing food, as the nucleated fragments. TJicy lack, Jioxvcver, the power 

 of digestion and secretion. Ingested food-matters may be slightly 

 altered, but are never completely digested. The non-nucleated frag- 

 ments are unable to secrete the material for a new shell {Polysto- 



