TYPES OF (ESTROUS CYCLE 65 



cycle is very meagre, the exact time of ovulation not being 

 known, even in the human. 



A tubal ovum has not yet been recovered in man and this 

 method of determining the time of ovulation is not therefore 

 available. Certain data are provided, however, by the history 

 of the corpus luteum. The presence of newly-formed corpora 

 lutea in the human ovary at fifteen to seventeen days after the 

 beginning of the previous menstrual cycle led Meyer (459), 

 Schroder (548) and Novak and TeLinde (475), among others, to 

 conclude that ovulation takes place between these times, i.e. 

 in the middle of the intermenstrual interval. Shaw's material 

 enabled him to narrow the time down to between the thirteenth 

 and seventeenth days. By the nineteenth day of the cycle the 

 corpus luteum is mature, and it remains unaltered until the 

 twenty-seventh day of the cycle. By the twenty-eighth day 

 signs of degeneration, synchronizing with the onset of menstrua- 

 tion, have appeared, and eventually, some eight months later 

 (560), a corpus albicans is produced. 



In Macaciis, ovulation (deduced from the recovery of tubal 

 ovaj has been found by Corner (123) to occur fourteen to fifteen 

 days, and by Allen (9) ten to fourteen days after the onset of 

 the previous menstruation. Apart from some notes by Allen on 

 the corpora lutea, little further appears to be known of the 

 ovarian cycle in monkeys. 



Vaginal and mamma rv cycles. Both Allen and Corner have 

 dealt with the vaginal cycle in Macacus. Their work makes it 

 evident that, while slight changes occur in the vaginal epithelium 

 and in the proportions of leucocytes in the smear, no striking 

 cyclic changes occur such as are found in the mouse and rat. 

 In other monkeys, notably Papio sps., extraordinary swelling of 

 the vulva occurs during the follicular phase. 



In the human, Papanicolaou (486) has claimed to be able to 

 detect all kinds of pathological conditions, as well as the normal 

 cyclic stages of the uterus and ovaries, by changes in the vaginal 

 smear. Dierks (160) has also described slight vaginal changes 

 during the menstrual cycle. King (322), however, obtained 

 negative results. 



In monkeys, mammary changes do not appear to have been 

 described during the ordinary menstrual cycle, though Heape 



P.S.O. E 



