THE EFFECTS OF HYPOPHYSECTOMY 



van Dyke, 1932.). Koyama (1930-31) found that the weight of 

 the brain of the rat hypophysectomized when immature was 



Fig. 13. — Normal (leftj and hypophysectomized (right) littermate female rats. 

 The rat at the right was hypophysectomized at an age of 39 days. Both rats were 

 killed at an age of 175 days. Weight of the normal rat, 267 g.; weight of the hypo- 

 physectomized rat, 113 g. 



the same as that of the normal rat if both were killed some 

 months later. He implied that growth of the brain had oc- 

 curred in the hypophysectomized rat. A reference to the 



[47 1 



