OVARY AND THE ANTERIOR PITUITARY BODY 159 



(b) The effect is exerted purely through the ovary, which is 

 caused to undergo precocious maturation and to 

 elaborate the oestrus-producing hormone. 



At about the same tim.e, Smith (S7S), having found that hypo- 

 physectomy in the rat stopped the oestrous cycle, had begun 

 to investigate the effects of 'implantations' of the pituitary body 



^ *f^^-i^< 



Fig. 58. — Luteal Tissue produced in sterilized Ovary of 

 Mouse by anterior Pituitary Preparations (cf. fig. 48). 



(576-9). As in Zondek and Aschheim's experiments, the im- 

 plants were not grafts, but rather intramuscular injections of 

 macerated tissue. Subcutaneous injection of saline suspensions 

 of anterior pituitary tissue have the same effect. Later Smith, in 

 collaboration with Engle, arrived at results substantially the 

 same as those of the German workers, i.e. that implantation of 

 anterior pituitary tissue into the immature animal causes the 

 rapid appearance of the uterine, vaginal, and ovarian changes 

 characteristic of oestrus. The duration of treatment necessary 

 is inversely proportional to the age of the animal. The im- 



