HYPOPHYSIS AFTER CASTRATION 443 



physes were taken as recorded by Hatai ('15). For changes 

 during the first month, material was taken at weekly, or semi- 

 weekly intervals. For changes after the first month, material 

 was taken at monthly intervals after operation, up to nine 

 months. Most of the operations were done by Dr. J. M. Stotsen- 

 burg of the Wistar Institute, to whom I am greatly indebted. 



The fixing fluids which proved most useful were the neutral 

 formol-Zenker mixture of Bensley ('11), and the neutral formol- 

 potassium bichromate fluid as employed in the mitochondrial 

 technique of Cowdry ('16). Others used in the early part of the 

 work were the fluids of Bouin, of Ohlmacher and the acetic- 

 osmic-bichromate mixture of Bensley. 



After embedding in paraffin, sagittal sections were cut at 

 3 or 4 microns. For staining were used Mallory's aniline blue- 

 orange G, iron hematoxylin, and Altmann's acid fuchsin fol- 

 lowed by methyl green, as detailed by Bensley and Cowdry. 



NORMAL HYPOPHYSIS 



In figure 1 are illustrated the four parts of the rat hypophysis, 

 as seen in median sagittal section. These parts are named, 

 (1) pars nervosa or infundibular portion; (2) pars intermedia, 

 or juxta-neural portion, (3) pars anterior, or ventral glandular 

 portion, and (4) pars tuberalis (Tilney). The pars nervosa is 

 connected with the base of the brain by a stalk which is solid, 

 except at its connection with the diencephalic floor, where it 

 contains a short extension of the third ventricle. The residual 

 pouch of Rathke (5, fig. 1) persists as a cavity between the pars 

 intermedia and pars anterior. Passing cephalad along the 

 hypophyseal stalk is a strand of cells (1 to 2 rows deep), constitut- 

 ing the pars tuberalis. Of these several parts of the hypophysis, 

 the ventral glandular portion is the one which shows the most 

 marked changes after castration, and is the only part which 

 calls for detailed description here. 



In the normal adult animal, the venttal glandular portion of 

 the hypophysis presents a compact arrangement of masses of 

 cells between the blood-vessels. The distribution of the blood- 

 vessels is best seen in sections parallel to the greatest surface 



