3o8 THE BIOLOGY OF STENTOR 



is to be found in the work of Popoff (1909) who concluded from 

 his observations of coeruleus that stentors with too little nucleus 

 are sickly and in many respects like enucleates. Schwartz (1935) 

 was even stronger in his statement that digestion and even ''the 

 entire metabolism" is greatly disturbed through removal of most 

 of the macronucleus. 



Although the old concept of nucleo-cytoplasmic ratio may not 

 have fulfilled the original hopes that were invested in it, it is likely 

 that the extreme variations in this ratio which can be produced in 

 Stentor will have an important bearing in newer studies of respira- 

 tion, synthesis, and enzyme production in single cells. 



Fig. 87. Critical time for recovery after renucleation. 



Macronucleus was excised from specimens on morning of 

 day I. If renucleated on day 4 complete regeneration of feeding 

 organelles and of nuclear chain occurred, with continued 

 survival. Renucleated on day 5, pale and murky stentor becomes 

 healthier, regenerates faded pigmentation, and forms primor- 

 dium which does not produce mouthparts. Specimen was dead 

 on day 10. Renucleation on day 6, the faded, murky specimen 

 became healthier in appearance and darker in color but died the 

 next day without forming an oral anlage. Fifth day therefore 

 seems to be transition period for recoverability of the cytoplasm. 



