PLATE 7 



EXPLANATION OF FIGURES 



20 A section of ovary from animal 1089 9 killed during the first stage of 

 oestrus. A ripe follicle is shown a few hours before congestion of the theca 

 begins. A smear of the vaginal fluid from the same animal is seen in figure 1 

 and sections of the uterus in figures 11, 12 and 13. 



21 A higher magnification of the ovum and follicular wall shown in figure 20. 



22 A section of the ovary from 1066 9 killed during the second stage of 

 oestrus. The theca folliculi surrounding the ripe follicle has become highly 

 congested, bv, blood vessels. 



23 Shows at a higher magnification a clearer view of the congested condition 

 of the follicle in figure 22, bv, blood vessels. The nucleus of the ovum is in a 

 resting condition. Corresponding vaginal smears from this animal 1066 9 just 

 before being killed are illustrated in figures 2, 3 and 4, and a section through the 

 uterus in figure 1-1. All of these figures illustrate commonly seen second stage 

 conditions. 



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