HISTOLOGY OF THE HYPOPHYSIS CEREBRI 713 



two anlagen quite independent of the pouch of Rathke, so that for the 

 present the question of the nature of this extension of anterior lobe 

 tissue, in the human hypophysis, remains open. 



Histology 



The general appearance of the three main divisions of the hypophysis, 

 as seen in a section passing from the anterior lobe proper through the 

 pars intermedia into the posterior lobe, is illustrated in Fig. 4. 



Fig. 5. Pars anterior of guinea pig's hypophysis fixed in Altman's fluid and 

 stained with fuchsin and methyl green, (a) Acidophil cells, (b) basophil cells and 

 (c). chief cells (magnification 1500). Area containing chiefly acidophil cells. Note in 

 some cells the heaping up of granules in the pole of the cell next the blood vessels in the 

 interstitial tissue, and that the chief cells (c) are often some distance removed from 

 the blood vessels. 



Pars Anterior Propria. The pars anterior propria consists, for the 

 most part, of epithelial cells arranged in clusters and columns separated 

 by a small amount of connective tissue. Sometimes acinus-like structures 

 with definite lumina are to be seen (Fig. 4). The clumping of the 

 cells is less apparent in lower mammals than in man. 



Cells Types. There is but little uniformity in the classifications of 

 the different cell types which have been proposed. The cells are usually 

 divided into chromophil cells, which stain deeply, and chromophobe cells, 

 which remain clear. In the chromophil cells it is customary to recognize 

 two groups, those with basophilic cytoplasm, and those containing acido- 



