ORIGIN OF THE CORPUS LUTEUM 



151 



since it lines a smaller cavity than before. The individual cells 

 are about the same size as formerly, but in many places are now 

 elongated into oval or spindle forms by the stresses of the col- 

 lapse, appearing to have slid upon each other as the granulosa 

 thickened. The theca interna is the layer most affected, in a 

 mechanical way, by the sudden collapse, for in some of the 



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Fig. 10 Portions of wall of recently ruptured Graafian follicle (sow in first 

 clay of oestrus, ova in tubes). X 330. a, Mallory's connective-tissue stain, 

 Bouin's fixation, b, Osmium tetroxide after formol fixation, showing distribu- 

 tion of fats, gran., membrana granulosa; th.int., theca interna; Ih.ext., theca 

 externa; memb. prop., membrana propria. 



folds it is violently torn apart, so that there are many wide 

 spaces either within the theca interna or between the two thecae 

 (fig. 11, tear). These spaces are occupied either by networks of 

 fibrin, which may be altogether devoid of cells, or contain an 

 occasional theca interna cell, or a leucocyte; or the space may 



