244 "THE BIOLOGY OF STENTOR 



5. Comparison of osmotic effects to cooling 



Following the speculations of Jacques Loeb, Greeley (1901) 

 tested whether increasing the osmotic pressure of the medium 

 surrounding coeruleus had the same effect as decreased temperature. 

 Reducing the environmental temperature to 2 °C not only quieted 

 the animals but produced a variety of pathological conditions, 

 including the disappearance of the feeding organelles and the 

 lateral striations — to mention two of the most interesting effects 

 which deserve checking. On rewarming, the '' rest of the cells " 

 apparently survived a couple of weeks but in only a few cases did 

 they regenerate. Cane sugar was said to give the same effects as 

 cooling, though a typographical omission in the published account 

 prevents our ever knowing the concentration employed. As we 

 shall see later, sugar causes shedding of the membranellar band, 

 but disappearance of the lateral stripes does not occur and they 

 merely collapse with the cell. Full regeneration followed sugar 

 treatments; therefore we presume that the treatment was mild 

 enough to allow the animals to survive. Loeb's conjecture concern- 

 ing the similarity between cooling and concentration of protoplasm 

 by loss of water through osmosis was therefore considered to have 

 been confirmed. 



Increasing the temperature to 25-28 °C apparently accelerated 

 division, as would be expected; yet we cannot give credence to 

 Greeley's account that within 3 to 4 hours there were many 

 successive divisions induced without marked decrease in size. 



6. Acceleration of division 



In addition to the strange account of accelerated division just 

 mentioned, Peters (1904) claimed that dilute solutions of KCl also 

 stimulate fission in coeruleus. The solution used was o-oi molar 

 or a bit stronger. NaCl solutions of comparable strength produced 

 a suppression of division instead. From the results it appears that 

 Peters probably did get an accelerated division. He was looking 

 for a specific, immediate impulse since the experiments were run 

 for only 6 hours. Many abnormalities were also encountered. 

 Apparently the peristomal band was shed in some specimens 

 (because regeneration occurred) although he did not say so 

 expHcitly. Unequal divisions and production of small blebs of 

 cytoplasm were reported. For a division experiment Peter's proce- 



