DEVELOPMENT OF THE OVUM. 85 



ovary ; the tunica albuginea, which forms a capsule for the ovary, 

 and the germinal epithelium, gradually atrophy over it, and at 

 last it bursts and discharges the ovum. 



Two opposite opinions exist among gynecologists as to the 

 period of rupture : (1) That it occurs at the onset of menstrua- 

 tion ; (2) that it has no relationship to the menstrual period. The 

 truth is, probably, that both are right. The majority of ova, 

 however, appear to be discharged at the menstrual period. 

 Whether ova are discharged from both ovaries at once, or from 

 only one, and whether one or more than one in a month, are points 

 not yet settled ; but the usual opinion is that one ovum is shed 

 each month, and only from one ovary. 



The Graafian follicle, after rupture, fills up with blood ; a 

 cellular tissue is soon developed within its cavity. If pregnancy 

 occurs this tissue forms a true corpus luteum, a large yellow body 

 as big as a pigeon's egg. If pregnancy does not occur, a false 

 corpus luteum is formed, a formation which begins to disappear 

 before the next menstrual period. Both forms lead to a cicatrix, 

 which is seen on the surface of the ovary. The ovary of an old 

 person is commonly covered with such scars. The Graafian 

 follicles may become cystic and give rise to enormous ovarian 

 tumours. 



The Fallopian Tube. — When the ovum drops from the ovary 

 it cannot easily escape the ciliated fimbriae of the Fallopian tube 

 which surround and clutch the ovary. In Fig. 6 1 the relationship 

 of the Fallopian tube to the ovary is shown. The tube may be 

 demarcated into three parts : (a) the isthmus or arm directed 

 outwards to the wall of the pelvis (J to 1 inch) ; (6) the forearm 

 or ampullary part, directed backwards on the lateral pelvic wall 

 above the ovary ; (c) the hand, infundibular, or fimbriated part, 

 folded backwards and grasping the free border and exposed 

 surface of the ovary. The tube is tethered by one of its fim- 

 briae to the cephalic pole of the ovary. 



Course of the Ovum in the Tube. — The cilia on the fimbriae 

 work towards the ostium abdominale, the abdominal mouth of the 

 Fallopian tube, which is situated at the bases of the fimbriae, and 

 carry the discharged ovum through the ostium within the 

 tube. The ostium abdominale is shut when the tube is 

 examined after excision ; the closure is probably due to reflex 



