PROBLEMS IN OBSTETRICS AND GYNECOLOGY 393 



previous to birth. As the epiblast layer increases in thickness, pro- 

 cesses of the underlying mesoblast of the Wolffian body extend out- 

 ward among the germinal cells, forming a network-like stroma, in the 

 meshes of which lie primordial ovums, frequently surrounded by 

 germ cells. Regarding the formation of the primary follicle, there 

 are differences of opinion. Most believe that the germ cells arrange 

 themselves around the ovum forming the primary ollicle, in later 

 life proliferating to form the membrana granulosa. In 1878, Foulis, 

 of Edinburgh, contended that the cells surrounding the primordial 

 ovums are derived from connective tissue, and lately Wendeler and 

 Clark have advocated this view. The latter has pointed out that 

 the cells are usually spindle-shaped in the early stages and that 

 frequently primordial ovums are found without any special layer 

 of cells surrounding them. Kolliker stated that the follicular epithe- 

 lium was derived from Wolffian epithelium, but this view has re- 

 ceived little support. Regarding the changes between birth and 

 puberty, we do not possess exact information. It is believed that 

 during this period more than half the primary follicles disappear, 

 though the manner and reason of the disappearance are not clear. 

 The period of puberty is characterized by the development of Graafi an 

 follicles, which rupture gives rise to the peculiar structure of the 

 corpus luteum. In some cases this phenomenon may be noted 

 months before the external signs of puberty are detected and oc- 

 casionally years previously. The explanation of these variations is 

 not known. Some degree of development of the ovum seems to be 

 a normal occurrence in the pre-puberty period. Stevens has recently 

 described these as follows: The follicle and contained ovum mature 

 to a certain extent. The single layer of flat cells surrounding the 

 dormant ovum proliferates and becomes somewhat cubical, several 

 layers being formed membrana granulosa. The ovum increases 

 and is surrounded by a discus proligerus; there is also a zona radiata 

 and liquor folliculi. At its greatest the follicle measures about .8X .7 

 mm.; the ovum, .IX .095 mm. The tunica fibrosa is well marked, 

 and resembles the ovarian stroma, being somewhat more vascular. 

 Sometimes excessive liquor folliculi collects. Retrograde changes 

 gradually develop. The ovum is invaded by cells, which are ap- 

 parently phagocytes, derived probably from the membrana granu- 

 losa. Their protoplasm is vacuolated and they do not resemble 

 leukocytes. Necrobiosis gradually develops, and most granulosa 

 cells disintegrate. The tunica fibrosa gets many capillaries and the 

 connective-tissue cells multiply. On the inner surface a hyaline 

 layer of fibrin forms, in which new connective tissue develops. The 

 follicle gradually shrinks, leaving a small scar area. It thus appears 

 that the pre-puberty changes in the follicles differ from those in 

 adult life in the following particulars: the ovum does not reach 



