35() C. M. JACKSON 



corresptjnds i-oiighly to that in younger normal rats of similar 

 body weight. 



11. In cell structure, the only change noted in the pars nervosa 

 during inanition is a variable degree of hyperchromatism in the 

 nuclei, which rarely may become shrunken and pycnotic. In 

 the pars intermedia, most of the cells usually suffer relatively 

 little change during inanition. The nuclei have a variable tend- 

 ency to hyperchromatism, occasionally becoming pycnotic, 

 especially in certain atrophic areas. The cytoplasm tends to 

 lose its granular structure, becoming more homogeneous and 

 often finely vacuolated in appearance. Around pycnotic nuclei 

 it is usually more strongly basophilic, and is much reduced in 

 volume in the atrophic areas above mentioned. 



12. The colloid which occurs normally in the pars nervosa 

 and in the h^^pophyseal cavity (residual lumen) appears un- 

 affected by inanition. 



13. In the pars anterior, the changes during inanition are 

 quite variable. Some areas may remain nearly normal, while 

 others, even in the same gland, show extreme changes of atrophy 

 and degeneration. The cytoplasm is usually reduced in volume 

 (as above shown) and is frequently much vacuolated. The 

 structure becomes sparsely granular and there is a marked 

 tendency to loss of the specific staining reactions, so that the 

 strongly chromophilic cells become weakly chromophilic or even 

 chromophobic. The nuclear changes are likewise variable, but 

 there is a very general tendency to hyperchromatism, often 

 reaching a definite pycnosis. Karyorrhexis and karyolysis are 

 rare. 



14. Upon ref ceding one-half week after the maintenance period 

 (three to twelve weeks of age), the hypophysis still retains the 

 typical inanition structure, although mitosis and growth have 

 begun. After one week of refeeding, some areas have become 

 nearly normal, and after two weeks the normal structure pre- 

 ponderates. After four weeks, the greater part of the hypophy- 

 sis appears nearly normal, although atrophic areas may persist 

 for indefinite periods. Recovery is improbable in cells whose 

 nuclei have reached advanced pycnosis. 



