GROWTH AND STRUCTURE OF HYPOPHYSIS IN RAT 351 



of cytoplasm, with perhaps a slight decrease in the hyperchro- 

 matisin of the nuclei in a few places. In general, however, it 

 would be difficult to distinguish this stage from that at the end 

 of the maintenance period. 



After one week of refeeding, however, some areas (especially 

 in the partes intermedia and nervosa) have become nearly normal 

 in histological structure. In the pars anterior, these areas are 

 more frequently found in the central region, and their extent 

 varies considerably in different individuals. In general, how- 

 ever, the structure characteristic of inanition still prevails over 

 the greater part of the gland. 



After two weeks of refeeding, the normal structure becomes 

 progressively more evident, and usually prevails over the greater 

 part of the gland. The cytoplasm and nuclei become nearly 

 normal in size and structure. Both pars intermedia and pars 

 anterior still retain atrophic areas, however, especially in the 

 periphery of the latter. 



Even after four weeks or more of refeeding, although the gland 

 in general has usually become nearly normal in structure, some 

 more or less atrophic areas may still persist. These are much 

 more frequent and extensive than the similar areas previously 

 mentioned as occasionally found in the normal gland, which 

 usually in^'olve only single cells or small groups. 



The recovery of the cells upon refeeding apparently depends 

 upon the extent of degeneration (especially of the nucleus) 

 involved during the inanition period. It is probable that nuclei 

 in the extreme stages of pycnosis are beyond the possibility of 

 repair, although they may persist in this condition for a long 

 time before disintegration and removal. 



DISCUSSION AND CONCLUSIONS 



The effects of inanition upon the hypophysis were studied by 

 Guerrini ('04). He found in the hypophysis (anterior lobe) of 

 4 dogs, 4 rabbits and 4 pigeons, during the first third of the acute 

 inanition period, a slight increase of secretory activity in the 

 cells, as indicated by a more intense reaction to Galeotti's stain. 

 In the remaining period of acute inanition, however, he found 



