CHANGES IN THE OVARY 



153 



The wonderful property which these cells possess of enlarging 

 within a very short time of ovulation is seemingly without a 

 parallel in the physiology of the Vertebrata, and it becomes 

 additionally interesting in view of the almost certain fact that 

 the cells, from which the luteal cells develop, are derived, like 

 the ova, from the original germinal epitheUum. 



During the later part of pregnancy the corpus luteum becomes 



Fie. 37. — Section through old corpus luteum. (From Sellheim.) 

 C, connective tissue ; L, luteal tissue. 



reduced in size, the luteal cells degenerating, losing their yellow 

 colour, and eventually (at least in some cases) appearing to 

 become transformed into cells resembUng, if not identical with, 

 the ovarian interstitial cells referred to above (see p. 148).^ At 

 the end of pregnancy the human corpus luteum has a diameter 

 not exceeding half-an-inch in length. 



* Schafer, Essentials of Histology, 7th Edition, London, 1907. The 

 similarity between the luteal and interstitial cells has also been remarked 

 upon by Allen, loc. cit. 



