252 



INTERNAL SECRETIONS 



functions after whatever intervals it reappears ; the function of 

 the corpus luteum is to prevent the return of the uterus to an 

 infantile state or to prevent climacteric atrophy of the uterus, 

 and, further, to render possible the transformations in the 

 uterine mucosa necessary for the fixation and growth of a 

 fertihzed ovum. If fertilization has really taken place, the 

 corpus luteum remains functional for a further period, assisting 

 in the uterine transformation and in the development of the 



Fig. 112. — Section through fresh corpus luteum of rabbit (Prot. Nr. 

 104). X 40. The c.l. protruding out of the surface of the 

 ovary. — Prepar. of Wagner; photo of KuU. 



ovum. If fertilization does not take place, menstruation sets 

 in, and the corpus luteum enters into regression. 



The experiments of Fraenkel were controlled and confirmed 

 by several authors; the question was studied especially by 

 L. Loeh (1910, 1917, 1918) and Bouin and Ancel (1910, 1911). 



L. Loeb has shown in numerous experiments that the produc- 

 tion of a deciduoma or a maternal placenta in the absence of a 

 fertilized ovum can be evoked, if a few days after spontaneous 

 ovulation incisions are made in the uterine mucosa. If the 

 ovaries or the corpora lutea are extirpated, the deciduoma is 

 not produced 



