336 THE PHYSIOLOGY OF REPRODUCTION 



little or nothing is known concerning the source of that dis- 

 turbed state of the nervous metabolism, the existence of which 

 during oestrus is so plainly manifested in the display of sexual 

 feeling. 



THE FUNCTION OP THE CORPUS LUTEUM 



Various theories have been put forward to explain the 

 formation and presence of the corpus luteum. According to 

 one view, which is still sometimes taught, the development of 

 this structure is merely a result of the excessive vascularisation 

 which characterises the entire internal generative tract during 

 the period of pregnancy. Very little consideration of the actual 

 facts is needed to convince one of the inadequacy of this ex- 

 planation. The blood supply to the generative organs is greatest 

 during the later stages of pregnancy, when the corpus luteum 

 is becoming diminished in size. Moreover, the rapid hyper- 

 trophy of the luteal cells takes place independently of pregnancy 

 during the very early stages of development at a time when 

 there is no appreciable congestion of the genital organs. Ac- 

 cording to another theory, the corpus luteum is of the nature 

 of a stop-gap, whose purpose is to preserve the cortical circula- 

 tion of the ovary by preventing an excessive formation of 

 scar-tissue. 1 



Prenant 2 seems to have been the first to suggest that the 

 corpus luteum was a ductless gland. He supposed it to produce 

 an internal secretion which exercised an influence over the 

 general metabolism in the manner attributed to the internal 

 ovarian secretion. The phenomenon of chlorosis was explained 

 as being due to the absence of this secretion. Prenant supposed 

 also that the corpus luteum had the further function of pre- 

 venting ovulation during pregnancy or between the oestrous 

 periods. 



This theory was supported by Regaud and Policard, 3 who 



1 Clark, " Ursprung, Wachstum, und Ende des Corpus Luteum," Arch, 

 f. Anat. u. Phys., Anat. Abth., 1898. Whitridge Williams, Obstetrics, New 

 York, 1903. 



2 Prenant, "La Valeur Morphologique du Corps Jaune," Rev. Gen. des 

 Sciences, 1898. 



3 Regaud and Policard, " Fonction Glandulaire de 1'Epithelium Ovarique 

 chez la Chienne," C. R. de Soc. de Biol., vol. liii., 1901. 



