HISTOLOGY OF THE HYPOPHYSIS CEKEBRI 715 



and resemble those occurring in other glands. They may be distinguished 

 from the other granules by their rod-like and filamentous shape. In lower 

 forms, Gemelli has described a reticular apparatus, comparable to the 

 Golgi apparatus of nerve cells. In his preparations it occurs in the form 

 of a loose network with large meshes blackened with silver. Addison has 

 confirmed and greatly extended Gemelli's results in mammals. The baso- 

 philic cytoplasm is often apparently homogeneous, but large discrete 

 granules staining intensely with basic dyes are not uncommon. The acido- 

 phil, or oxyphil granules are very conspicuous, and are thought by 

 Benda to represent the true secretory antecedents of the gland. 



Effects of Various Conditions on Hypophyseal Cells. (1) Preg- 

 nancy. The chief cells undergo remarkable changes during preg- 

 nancy. Erdheim and Stumme have found that they increase greatly 

 in number, becoming even more abundant than the acidophil cells. They 

 increase also in size and their cytoplasm becomes faintly acidophilic. 

 After the termination of pregnancy they resume their old properties, but 

 the increase in number is never entirely lost. The process is repeated at 

 the next pregnancy. 



(2) Castration. Kohn observed an increase in the number and size of 

 the chief cells three years after castration. Addison (b) has made a careful 

 study of the effect of castration in the rat. He found that "the basophils 

 increase in size and number. The largest begin to become vacuolated at 

 two months after operation. During succeeding months the number of 

 vacuolated cells increases; the largest become ringshaped, with cytoplasm 

 and nucleus at the periphery, and the central part made of the colloid 

 containing vacuole. The acidophils are not much affected at first, except 

 for a slight diminution in average diameter. Gradually some of them show 

 a diminished number of granules and lessened stainability. At seven 

 months after castration the number of distinctly stained acidophils is 

 decidedly reduced. Some of the reserve cells in the first months after 

 castration appear to become basophil cells. In the later months some of 

 the acidophils appear to gradually dedifferentiate into reserve cells." 



Addison did not observe the great increase in acidophil cells which is 

 usually recorded. 



(3) Endocrin Gland Extirpation and Administration. According to 

 Kojima's(&) observations, total thyroidectomy causes in the rat a deposi- 

 tion of hyaline substance in the pars anterior. Addition of thyroid, ante- 

 rior lobe, and epinephrin to the food all cause an increase in the number of 



.acidophil cells. lodids, on the other hand, bring about a reduction in 

 both the acidophils and basophils. Parathyroidectomy exercises a similar, 

 though less apparent effect. Whatever the relationships of these different 

 cells in the anterior lobe, a delicate balance is maintained through the 

 growth and differentiation of the chief cells, 



(4) Hibernation. The hypophysis undergoes marked alterations in 



