446 WILLIAM H. F. ADDISON 



The differential staining of the cells to show the three types 

 requires considerable care. With routine stains, the cells do 

 not stain so distinctively as those of man, or of some of the 

 domestic animals. Stendell ('14, p. 116) found that this part 

 of the hypophysis of Mus and Cavia stained less intensely than 

 that of Lepus. Good differential staining of the acidophiles so 

 as to distinguish them from reserve cells is not easily accomplished 

 by eosin. A better method for the acidophilic granules is the 

 acid fuchsin method of Altmann, or as variously slightlj'^ modi- 

 fied. With this stain one finds that the granules of all cells are 

 not equally deeply stained,- and this is probably due to the cells 

 being in different states of functional activity. The granules 

 are found to be very minute and individual ones are less easily 

 definable than in the human or cat hypophysis. In the Mallory 

 methylene blue-orange G method, the acidophilic granules are 

 of orange-yellow color and, when the staining is successsful, I 

 think that by this method one can best differentiate the acido- 

 philes from the reserve cells. By this method, too, the cytoplasm 

 of the basophiles is stained blue, thus giving good contrast 

 with the acidophiles. The nuclei are also stained blue but they 

 are usually easily made out. The cytoplasm of the reserve 

 cells is grayish and practically unstained, and the cell boundaries 

 are often indistinct. With this stain at least six weeks old, 

 good preparations are usually obtained after 20 minutes staining. 

 Care must also be taken in differentiating, as there is apt to be 

 considerable variation in the depth of color in different prepara- 

 tions. Wittek ('13) and Trautmann ('09) agree that, while the 

 basophiles are to be found in all the domestic animals, they are 

 as a rule, less distinct than the acidophiles. 



While colloid substance is found characteristically in many 

 hypophyses, there is, as a rule, very little if any to be seen in the 

 hypophysis of the normal albino rat. As an exception, it does 

 occur in considerable quantity and then is seen in the residual 

 lumen of the pouch of Rathke, and in small masses in the vas- 

 cular channels of the ventral glandular portion of the hypophysis 

 but not in the other parts of the hypophysis. 



