Histological Appearances of tlie Mammalian Pituitary Body 135 



the deeply-staining cell may be quite as large. In fig. 7 it looks as though 

 there were two kinds of cells : a large, clear, and diffusely granular kind, and 

 a smaller, deeply-staining cell. The picture presented by these cells varies 

 according to the method and depth of staining, and differs in different parts 

 of the lobe in the same section. The fixative employed has also a great 

 influence on the staining reactions, and with formalin or corrosive sublimate 

 fixation there appear to be only two kinds of cells : the granular and clear. 

 Occasionally a cell is seen which is diffusely granular in most of its body, 

 but contains around its nucleus protoplasm of the deeply-staining variety. 

 It is extremely diflicult to decide whether these appearances indicate 





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Fi( 



7. riinioi^'rapli (if part of a;;'ii i . - :. ;■ " t cat, x 500. 



Fi.xed in Flemining's solution, staiiird with hot ah?oholi(j eosiu, ditteventiated 

 in alkaline alcohol, and counterstaiiied with picro-fuchsine. 



Shows clear cells and granular cells. The latter appear to be of two varieties — one kind 

 consists of large cells whose protoplasm takes on a diffuse stain ; the other of smaller 

 cells which are full of deeply-staininj; granules. The blood-channels are collapsed 

 and their position is indicated by the dark lines. 



distinct forms of cells, or whether they are merely expressions of different 

 functional stages of one and the same kind of cell. 



The different cell forms are distributed fairly uniformh" throughout the 

 lobe ; the clear cells sometimes predominate in certain localities, but are not 

 constantly distributed in these positions. Where anterior lobe blends with 

 the epithelium of the pars intermedia, a gradual transition is sometimes 

 seen between the two kinds ; at other times the dividing line is sharply 

 marked (cf. fig. 8). The cells typical of the anterior lobe may spread right 

 round the neck of the posterior lobe, or backwards over the body of tlie 

 posterior lobe to the posterior reflection of epithelium. The general 

 appearances of the relation of the cells of the anterior lobe to the cleft and 



