GROWTH AND STRUCTURE OF HYPOPHYSIS IN RAT 349 



ti^'e ill character, were observed by Schoneiiiaini ('92) in the 

 pars anterior of the himian hypophysis, and by Stendell ('14) 

 in the rat. 



During inanition, the changes in the parenclijana cells of the 

 pars anterior are similar in the young rats held at maintenance, 

 and in older rats subjected to acute and chronic inanition. As 

 might be expected, the changes are usually more marked in 

 cases where the inanition is more protracted or severe. The 

 changes vary greatly even in different parts of the same indi- 

 vidual, so that great care is necessary in drawing generalized 

 conclusions. Some areas may even remain nearly normal in 

 appearance, while others show^ extreme changes of atrophy and 

 degeneration. In general, such changes are usually found more 

 marked and extensive in the peripheral portions of the gland. 

 The surrounding pressure might render the surface layers of an 

 organ somewhat more prone to atrophy, but it is difficult to 

 understand why this should be so pronounced in the case of the 

 hypophysis. 



As already shown, there is during inanition usually a marked 

 loss in the volume (both relative and absolute) of the cytoplasm. 

 Even in areas retaining a considerable amount of cytoplasm, its 

 structure frequently becomes coarsely vacuolated. In other 

 cases (especially during maintenance and chronic inanition) 

 these vacuoles apparently coalesce to form a watery intercellular 

 substance, leaving the nearly naked nuclei surrounded by a thin 

 layer of cytoplasm (fig. 3). On account of such changes, together 

 with the hyperemia characteristic of inanition, it is evident that 

 the loss in protoplasmic substance may be (and usually is) pro- 

 portionately much greater than the loss in gross weight of the 

 gland. 



The cytoplasm also tends in general to lose its specific stainhig 

 reactions. The strongly chromophilic types stain more faintly, 

 and the weakly chromophilic become chromophobic. In extreme 

 cases, and in areas of marked atrophy, all cells may become 

 chromophobic, with no trace of acidophilic or basophilic reac- 

 tions. For the most part, however, the cytoplasm does not 

 reach this stage, but becomes more or less sparsely granular, 



