114 INTRODUCTION TO SEXUAL PHYSIOLOGY 



secretion, which promotes rhythmic uterine contractions, is 

 inhibited ; but that when the corpus has reached a certain 

 stage of invohition, the ovarian endocrine mechanism, which 

 probably works partly through the intermediation of the 

 pituitary, resumes its activity, and the tolerance of the uterus 

 for the foetus no longer continues, so that the uterus, respond- 

 ing more readily to internal stimidi from the developed foetus, 

 contracts strongly, and birth is the result. 



