PLATE 4 



EXPLANATION OF FIGURES 



10 A section of the resting uterus during dioestrum, four and one-half days 

 "after oestrus, showing the normal cuboidal ciliated epithelium — animal 1074 9 . 



11, 12 and 13 Sections showing the condition of the uterine epithelium dur- 

 ing its active secretion of mucus and the beginning of the leucocyte migration, 

 from animal 1089 9 in which the oestrus was just commencing — leu, leucocytes. 

 Note the contrast with figure 10. A corresponding smear of the vaginal fluid 

 from the same animal just before it was killed is shown by figure 1. 



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