Studies on the Endocrine C}lan<ls 321 



so that we are unable to gather wluit the gain of weight of the pituitary 

 body was in proportion to the body-weight, although it is evidently much 

 larger relatively. 11'^ further found that on sul^cutaneous injection of 

 testicular extract into the castrated animals the above changes in the 

 pituitary did not ai)pear, or, if they were present, disappeared. According 

 to Cimoroni (22), the changes in the pituitary Vjody which follow castra- 

 tion are similar to those which follow thyroidectom}^ (dogs) i\Iarassini 

 and Luciani ( 28) found that in the sheep, domestic fowl, rabbit and guinea- 

 pig the oxyphil (eosinophil) cells, which are normally abundant, exhibit 

 little or no change in size and number, nor is any effect caused on the 

 weight of the pituitary as the result of castration. They notice, however, 

 an exception in the case of the cock, where, as the result of castration, there 

 is a distinct enlargement of the pituitary, accomjjanied by the appearance 

 of very voluminous cells the cytoplasm of which is granular and stains 

 deeply with hematoxylin. They, however, regard these changes as 

 essentially due to alterations in jreneral metabolism and not a direct effect 

 upon the gland. According to Kolde (24), in rabbits and guinea-pigs 

 the pituitary body increases in weight after castration, and there is an 

 accompanying increase in the oxyphil cells. Hatai (25) also found an 

 increase in weight of the pituitary in male rats after castration. Living- 

 stone (26), on the other hand, states that neither male nor female rats 

 show any constant hypertrophy of the pituitary as the result of castration ; 

 if anything, the pituitary is more often responsive in the female to the 

 removal of the genital glands than in the male. Biedl (27), who gives the 

 re.sults of experiments carried out by Zacherl upon rats, states that the 

 pituitary body undergoes enlargement after castration in both sexes. He 

 finds the oxyphil cells relatively diminished in number ; but big cells of a 

 swollen character make their appearance. The nuclei of these cells are 

 only faintly stained by haematoxylin : the cytoplasm is beset with fine 

 granules and contains small vacuoles. Cells of this character are scattered 

 either singly or in strands within the pars anterior. Biedl considers 

 that these large cells are to be regarded as exhibiting end-stages of the 

 process of secretion of the oxyphil cells. 



Present Investigations. 



Microscopic Appearances of the Pituitary Body of the Rat. 



Under the microscope the pars anterior of the normal rat has a 

 compact and very vascular appearance (fig. 1). When the vessels are 

 filled with blood the capillaries are dilated so as to appear like sinuses. 

 Oxyphil cells are present in great number in the pars anterior, mixed 

 with other kinds of cells, and showing no distinct localisation. They are 

 nearly uniform in size, but their shape varies considerably. Their cyto- 

 plasm is compact and finely granular ; their granules are stained red by 

 eosin. Their nuclei, which are for the most part circular and uniform in 



