HYPOPHYSIS AFTER CASTRATION 445 



In the young mature animal (e.g., 69 days old, figure 2) two 

 of these three types are very distinct, and the third is without 

 such distinct characters. The two distinct glandular types are 

 the acidophiles and the basophiles, and they together form the 

 continuous lines of glandular cells, abutting upon the endothelium 

 of the blood-streams. Away from the sinusoids are located the 

 reserve cells. In the groups of reserve cells between the sinu- 

 soids are seen also acidophiles and basophiles, but it would appear 

 that all these latter cells come into close relationship with a blood- 

 vessel, either above or below the plane of section. The reserve 

 cells, however, do not usually form part of the lining glandular 

 cells of the blood-channels in the normal mature hyophysis. 



Taking a survey of entire sagittal sections, the acidophiles 

 always outnumber the basophiles, and as a whole occup3^ a 

 greater proportion of the section, although the basophiles are 

 individually usually larger. The number of the reserve cells 

 varies ^^ith the age of the individual, being more numerous in the 

 immature animal, and becoming as a whole less conspicuous in 

 the full-grown. As will be seen later, their number may also 

 vary with the functional conditions of the animal. All types 

 are found intermingled throughout the section in a fairly uni- 

 form manner, although sections from different animals may show 

 some definite local variation in the proportionate number of the 

 cells. The most constant variation from the uniform grouping 

 was found in a limited area at the attached end of the hypophj^sis, 

 where the basophiles were present to the nearly entire exclusion 

 of the acidophiles and reserve cells. The basophiles of this 

 group become very coarsely granular as age increases. Another 

 variation seen in sections from several different specimens, was 

 a greater proportion of basophiles along the most ventral border 

 of the gland, and a decreased proportion of basophiles in the 

 marginal zone along the caudal half of the pouch of Rathke. 

 In general, in the central part of the caudal half of the sections, 

 the acidophiles were always present in increased proportion to 

 the basophiles. In Mus decumanus, Tilney ('11, page 48) 

 found the acidophiles occupying the central regions of this 

 part of the hypophysis. 



