250 SOME ASPECTS OF CELL-CHEMISTRY AND CELL-PHYSIOLOGY 



accounts of his predecessors in regard to regeneration, added many 

 extremely important and significant results. Non-nucleated frag- 

 ments both of infusoria (e.g., LacJiryinarid] and rhizopods (Poly- 

 stouiclla, TJialassicolla) 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. They lack, however^ tJie power 

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



Fig. 112. Regeneration in the unicellular animal Stentor. [GRUKER.] 



A. Animal divided into three pieces, each containing a fragment of the nucleus. B. The 

 three fragments shortly afterwards. C. The three fragments after twenty-four hours, each regen- 

 erated to a perfect animal. 



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

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

 melld) or the slime by which the animals adhere to the substratum 

 (Amceba, Difflugia, Polystomclld}. Beside these results should be 

 placed the well-known fact that dissevered nerve-fibres in the 

 higher animals are only regenerated from that end which remains 

 in connection with the nerve-cell, while the remaining portion inva- 

 riably degenerates. 



These beautiful observations prove that destructive metabolism, as 



