METABOLISM 261 



as a reserve is indicated by the often poor survival of hypernucleated 

 stentors (p. 304). 



It was Johnson (1893) who first noted that dwarf stentors have 

 smaller and fewer macronuclear nodes than well-fed animals at 

 any stage, and Prowazek (1904) provided further confirmatory 

 observations. AUescher (19 12) made a separate study of this 

 phenomenon. First she found, naturally, that decrease in size of 

 starving stentors was greatest at higher temperatures, at which 

 metabolism would be expected to proceed at a higher pace; but 

 rate of decrease also then fell oflF rapidly, as if definite limits to 

 reduction in size were met. Cool and warm cultured animals 

 eventually shrunk to the same small size. Apparently the nucleus 

 decreased but little at lower temperatures, while in warm cultures 

 under starvation decrease in the size and especially in the number of 

 macronuclear nodes was conspicuous: of the order of from 20 to 5. 

 In this reduction some of the nodes decreased in stainabiHty as 

 their substance was apparently transferred to adjacent beads of 

 the nucleus. The reduction was therefore especially one of surface 

 area. Her interpretation was that the nucleus as well as the 

 cytoplasm was consumed during starvation and that this is possible 

 in ciliates with widely dispersed macronuclei, such as Stentor and 

 Dileptus, but not in forms with compact nuclei, like Paramecium. 

 I have found, indeed, that P. caudattim forced to carry two 

 macronuclei do eventually resorb one entirely, instead of diminish- 

 ing both (Tartar, 1940). Perhaps it might with equal plausibility 

 have been suggested that paramecia cannot decrease the nuclear 

 surface further, while stentors with their nodulated nucleus can 

 and do, in adaptation to decreasing size. 



In a clone of coeruleus I made some observations on starvation 

 dwarfs simply by isolating abundant samples in caster dishes and 

 allowing them to stand for a month without added nutrients. The 

 size of the ciliates decreased from a maximum diameter of 376 /x 

 to a minimum value of 94 /z. After two weeks of starvation the 

 nuclear picture was varied, for the number of nodes ranged from 

 6 to 16 and large and small nodes were frequently found within 

 the same individual. This indicates that the nucleus was still in 

 process of adapting to decreasing size of the animals. Eventually 

 the dwarfs contained only 5 or 6 nodes which were still large in 

 proportion to the volume of the cell yet smaller than those of 



