§ 2 HISTOGENESIS OF CORPORA LUTEA 91 



f'^Ti^:*.- 



_X— /migrating cells 



decay of cell: 



Fig. 67. Corpus luteum, }'-stage. Decay of the already largely inactive 



corpus luteum; appearance of corpus-luteum pigment in the lutein cells. 



Loosening and migrating cells; a few, fully secreting granulosa cells. 



mass. Only on the extreme edge is a little of the theca, con- 

 sisting of connective tissue, still recognizable " (Figs. Sy and 

 68). 



The cells of the corpus luteum become smaller and fewer 

 with the successive stages of degeneration, and our investiga- 

 tions have shown that in the a- and /5-stages the number of 

 cells increases considerably, whereas with the completion of 

 the /5-stage it rapidly decreases to zero. 



This decrease in the number of cells takes place in two 

 different ways: by migration of the cells and by necrosis 

 fFigs. 6 J and 68). The migration of the exhausted corpus 

 luteum cells is preceded by a re-differentiation. Owing to 

 the disappearance of the vacuoles during the preceding stage, 

 the cytoplasm becomes denser. The pigment disappears again; 



