The Ovaries 13 



not make it clear whether epidermal cells may thus reach this 

 region or not, nor whether the presence of this gubernaculum 

 accounts for the occasional inclusion and development within the 

 genital glands, of epidermal structures. 



It is also alleged. by some embryologists that the Wolffian ducts 

 are of epiblastic origin and are formed from a longitudinal in- 

 vagination of epiblast. 



In the outermost layer of genital epithelium, the cells are 

 columnar while, deeper, they are cuboidal in form. In the deeper 

 parts, the skeletal stroma divides the cuboidal or spherical cells 

 into clumps or groups known as egg columns, among which are 

 to be seen, usually one or more in each nest, cells of large size 

 with prominent nuclei, the primitive ova, which continue to 

 form until near the close of intra-uterine life. Primitive ova are 

 present as soon as the genital ridges are well formed and Nagel 

 claims that these are not confined strictly to the genital ridges, 

 but occur here and there in the region of the ducts of Mueller in 

 the thickened epithelium. 



This observation of Nagel is highly suggestive in reference to 

 the operation of ovariotomy in females. We frequently find 

 reports of cases where females have been castrated and later have 

 shown signs of estrum, and it has been held by many practitioners 

 that certain of our domestic animals continue to show signs of 

 estrum after they have been properly castrated. In our own 

 experience, we have seen estrum recur in an aggravated form — ■ 

 nymphomania — in the case of cows, where we were sure that we 

 had removed the ovaries completely. Operating a second time, 

 we have found cystic Graafian follicles at the point of removal of 

 the ovary. It would consequently seem that not only may 

 these ova exist in the tissues somewhat outside the ovary, but, 

 when the gland itself has been surgically removed, they are 

 capable of developing ovisacs, especially in a cystic form which 

 will later produce all the symptoms of estrum, but probably 

 have no living ova in them. These facts suggest to us that, in 

 performing ovariotomy, the operation should not be confined to 

 removing the ovary, but should include a large part, if not all, 

 of the oviducts, with the contiguous tissues, .so as to be sure that 

 the ova and ovisacs are all removed. 



It is contended by Nagel that there are differences in the geni- 

 tal ridges of the sexes in the human embryo at as early a period 



