1134 THE REPRODUCTIVE ORGANS 



turing of the Graafian follicle and the discharge of the ovum. Pfliiger 1 

 sought its cause in a reflex extravasation of blood evoked by the pres- 

 sure which the growing follicle exerts upon the nerves of the ovary. 

 This view, however, was put into question by the clinical experience 

 that ovulation and even pregnancy may result before the first menstrua- 

 tion as well as after the menopause. 2 It was also noted that conception 

 may take place during the period of lactation, whereas the menstrual 

 flow is then usually absent. Lastly, it has been observed by Rein 3 that 

 pregnancy is possible in dogs even after all the nerves connecting the 

 uterus with the spinal cord have been divided. Certain experiments 

 are also at hand to show that menstruation does not cease after the 

 transplantation of the ovaries into some other part of the body, while 

 ovulation is then impossible. In 1871, Sigismund advocated the view 

 that menstruation succeeds ovulation and is the direct result of the 

 failure of the ovum to become fertilized. It has also been stated that 

 menstruation is a process of purification and, therefore, serves to clean 

 out the uterus and to establish a proper substratum for the fertilized 

 ovum to grow upon. 4 



Subsequent to the development of the hormone doctrine, Frankel 5 

 proposed the theory that menstruation is dependent upon the forma- 

 tion of an internal secretion by the corpus luteum which controls the 

 blood supply of the ovary. 6 He believed ovulation to be related to 

 this process only in so far as the escape of the ovum initiates the forma- 

 tion of the corpus luteum which attains its full development about 7 

 days later, i.e., at a time when menstruation sets in. Consequently, 

 ovulation must take place 19 days after the last menstrual flow. 

 This explanation has many points in its favor, and may be supported 

 by strong clinical evidence. In the first place, it is obvious that men- 

 struation is dependent upon some activity of the ovaries, because the 

 removal of these organs gives rise to an artificial menopause which is 

 characterized by a cessation of the menses and an atrophy of the 

 uterus. Secondly, this cessation of the menstrual flow does not result 

 if the ovaries are transplanted into the uterus or elsewhere in the 

 abdominal cavity. 7 Thirdly, menstruation may be made to recur by 

 grafting a piece of an ovary in the uterus or under the skin of the 

 abdomen, 8 and a temporary condition of estrus may be incited in 

 mature animals by the injection of an extract of ovaries taken from 



1 Bedeutung and Ursache der Menstruation, Berlin, 1865. 



2 Berliner klin. Wochenschrift, 1871. 



3 Pfluger's Archiv, xxiii, 1880, 68. 



4 Bryce and Teacher, Early development of the human ovum, 1908. 

 6 Archiv fur Gyn., 1910. 



6 The dried extract of the corpora lutea of cows is made use of in the treatment 

 of suppressed menstruation and the grave symptoms sometimes following the 

 removal of the ovaries and premature production of the menopause. 



7 Halban, Deutsche Gesellsch. fur Gyn., ix, 1901; also: Glass, Medic. News, 

 1899, and Morris, Med. Rec., 1901. 



8 Meredith, Brit. Med. Jour., 1904. 



