148 THE PHYSIOLOGY OF REPRODUCTION 



The characteristics of the corpus luteum at different stages of 

 pregnancy have been described by van der Stricht, 1 Corner, 2 and 

 others. At first the luteal cells contain a large quantity of fat or 

 lipoid which is epithelial in nature. This decreases, but at a later 

 stage there is a reappearance of fatty material due to senescence. 

 Before retrogression sets in there is a diversity in the character of 

 the cells, some showing considerable peripheral canalisation while 

 others show only endoplasm. 3 According to Corner the corpus luteum 



FIG. 43. Section through old corpus luteum. (From Sellheim.) 

 C, Connective tissue ; L, luteal tissue. 



of pregnancy is distinguished from that of ovulation by the more 

 regular and uniform morphology of the former, and the greater 

 infiltration of fat in the latter. 



1 Van der Stricht, " Sur le processus de 1'excretion des glandes endocrines," 

 Arch, de Biol., vol. xxvii., 1912-13. This paper deals with bats. 



2 Corner, "The Corpus Luteum of Pregnancy, as it is in Swine," Contributions 

 to Embryology, Carnegie Institution, Washington, 1915. This paper goes into 

 great detail and gives numerous references. 



3 See also Delestre, " Recherches sur le Follicle de Graaf et le Corps Jaune 

 de la Vache," Jour, de Fanat. et physiol. (etc.), vol. xlvi., 1910 ; Hegar, " Studien 

 zur Histogenese des Corpus Luteum und seiner Riickbildungsprodukte," 

 Arch. f. Gyn., vol. xci., 1910 ; and Drips, " Studies on the Ovary of the 

 Spermophile, etc.," Amer. Jour. Anat., vol. xxv., 1919. The last paper describes 

 three phases (red granules, lipoid droplets, and regression). 



