548 W. W. SWINGLE 



Contrary to the findings of most of the investigators, recorded 

 above, Traina maintains that the changes which the testes of 

 starved animals suffer are by no means marked. Even where 

 there is a loss of weight as high as 20 to 25 per cent, spermatogen- 

 esis is maintained in adult animals. This author states that only 

 when the loss of weight becomes as high as 30 to 35 per cent 

 does spermatogenesis cease, but that even then one finds division 

 figures in the spermatogonia and spermatocytes. 



Von Hansemann observed that in hibernating marmots, sper- 

 matogenesis ceases, and that the interstitial cells almost disap- 

 pear. In certain non-hibernating animals, on the other hand, 

 the interstitial cells of the testes are very abundant. 



Morpurgo ('88) found that in animals subjected to inanition, 

 cell multiplication persists longer in the sex glands than in any 

 other organ or tissue. 



Schultz ('04) has shown that the male germ cells of Planaria 

 lactea are more resistant to the effects of starvation than are 

 other body cells. 



In many of the investigations just quoted, no results of micro- 

 scopic examination are reported, and in others, where such ex- 

 aminations were made, the results conflict. This rather extensive 

 review of the literature is thought justifiable in view of the dis- 

 parity of the results obtained by various investigators. 



MATERIAL AND OBSERVATIONS 



Throughout the present experiment, the larvae of Rana pipiens 

 were used. They were reared from the egg in the laboratory, in 

 order that the exact age of each tadpole could be determined. 



Two groups of eggs were started the same day, the larvae de- 

 veloping from one culture were destined to serve as future con- 

 trols for the other group. Both series of eggs were kept under 

 uniform conditions of light, temperature and water supply, 

 throughout the experiment. The eggs developed rapidly, and 

 when the young larvae had escaped from their gelatinous cap- 

 sules and developed to the free feeding stage (which occurred 

 about April 10) the animals of the culture intended for controls 



