ANATOMY OF THE PITUITARY BODY 



cells in the pars intermedia of the pig: one, making up the 

 bulk of the structure, was characterized by a granular cyto- 

 plasm; the other appeared to be a colloid-secreting cell. The 

 colloid of the pituitary body, which usually accumulates in 

 the residual lumen or in irregular vesicles and blind tubules 

 lined by cells of the pars intermedia, has been considered by 



Fig. 8. — Photomicrograph of the pars intermedia of the monkey {Macaca mulat- 

 ta). Haematoxylin and eosin. X8oo. Pars neuralis to the right; residual lumen 

 containing colloid to the left. 



some to be a true secretion. The evidence in favor of this 

 view is largely histological and will be discussed later. 

 Others, like De Beer, look upon accumulations of colloid as 

 representing "degeneration phenomena." About i per cent 

 of the bulk of the adult human pituitary appears to consist 

 of colloid (Rasmussen, 1927-28, 1934). 



Considerable amounts of a melanin-like pigment may be 

 found in the pars intermedia of the black or piebald rat, 



[17] 



