PHYSIOLOGY 



95 



cat, bird, turtle, frog, and fish, on Paramecium and Stylonychia, 

 Budington and Harve}^ (1915) noticed also that all extracts in- 

 creased the division rate. 



Flather (1919) saw the contraction of the contractile vacuoles 

 of Paramecium accelerated by adrenaline and pineal extract. Cori 

 (1923) noted the acceleration (about 12 per cent) of the division 



Fig. 38. Form and size variation in Tetrahymena vorax, due to differ- 

 ences in kind and amount of food material, as seen in life. X400 (Kidder, 

 Lilly and Claff). a, bacteria-feeder; b, c, saprozoic forms; d, individual 

 which has fed on killed Colpidium camjnjlum ; e, starved individual from 

 a killed-Oolpidium culture; f-i, progressive form and size changes of 

 saprozoic form in the presence of living Colpidium; j, a young carnivore 

 which has been removed to a culture with living yeast. 



