560 



UTERUS AND ITS APPENDAGES. 



cess occurs in the rabbit. Here is represented 

 a portion of a ripe Graafian vesicle, which was 

 upon the point of discharging an ovum. The 

 follicle, after being dissected out of the ovary, 

 has been subjected to slight lateral pressure in 

 the compressorium, by which the follicle has 

 been burst at the point (//) preparing for rup- 

 ture. The ovisac has given way at the thin- 

 nest point, and the ovum, surrounded by the 

 tunica granulosa (g, 1.), and dragging after it 

 portions of the retinacula (g, 2.) is shown in 

 the act of escaping from the follicle. 



Fig. 383. 



Ovum of the rabbit in the act of escaping from a rup- 

 tured Graafian follicle. (After Barry.) 



The ovum is surrounded by the tunica granulosa, 

 g\ and draws after it the portion of membrana 

 granulosa termed the retinacula, #2 . a t h, where the 

 rupture has taken place, the coats of the follicle are 

 attenuated, and towards this spot numerous vessels 

 converge. 



The form and size of the aperture by which 

 the ovum escapes varies considerably. In 

 the rabbit it generally appears in the form of 

 a small round aperture in the midst of a bright 

 red spot, which is margined by a little net- 

 work of capillaries filled with blood (Jig. 383. h). 

 In the sow the aperture is generally oblong 



Fig. 384-. 



Portion of ovary of the sow. Three of the largest 

 follicles have burst simultaneously, and exhibit wide 

 lacerations. Others, less forward, remain unrup- 

 tured. At the base are several unripe follicles. 

 (After Pouchet.) 



(Jig. 384.), and from li to 7"' in length; the 

 laceration in the latter sometimes extending 

 through the entire diameter of the follicle, and 

 permitting the .escape of the whole of its con- 

 tents, together with the ovum. 



The laceration is not necessarily limited to 

 a single follicle. In multiparient animals 

 (Jig. 384.) all or a greater portion of those 

 follicles which have attained their full de- 

 velopment undergo laceration, and emit their 

 ova about the same time. In some of these, 

 however, the effort may prove abortive, and 

 the follicles may remain stationary until an- 

 other impulse to rupture occurs, and the ova 

 may then be discharged, or may, on the other 

 hand, perish or be absorbed. 



In Man, although generally uniparient, two 

 or more follicles may likewise become ma- 

 tured about the same time, and their bursting 

 may take place simultaneously. Of this fact 1 

 possess the proof in a case (fig. 409. page 605.) 

 in which I found in one ovary three distinct 

 apertures leading to as many developed ovisacs, 

 all of which presented the characters just de- 

 scribed as indicating the recently ruptured 

 follicle. In this case the woman died during 

 menstruation. 



Such an observation is interesting, as show- 

 ing in what way multiple pregnancies may 

 occur in the human subject, for the whole 

 of the ova discharged under such circum- 

 stances may be impregnated by a single coitus ; 

 although it is also possible that the bursting 

 of one follicle only may suffice for the pro- 

 duction of twins, since two ova have been 

 several times observed in a single follicle in 

 the Mammalia, and this may also possibly be 

 sometimes the case in Man. 



Before proceeding to the consideration of 

 the remaining changes which the Graafian 

 follicle undergoes, it may be useful here to 

 make one or two observations on the con- 

 ditions already described. Up to the moment 

 of rupture, the progress of the follicle is one 

 of regular advancement from an embryonic 

 condition to a state of full maturity. The 

 object of this progressive advancement is the 

 protection, maturation, and final expulsion of 

 the ovum, in such a manner that this last step 

 may occur at a time when the ovum will be 

 placed in circumstances the most favourable 

 for impregnation. 



In order to accomplish this, the ultimate 

 purpose of all these progressive changes, the 

 ovisacs which had been previously set more 

 or less deeply in the ovarian parenchyma 

 reach, one by one, the surface of this organ, 

 and there, swelling rapidly from the increased 

 secretion into their interior, and the growth 

 of their walls, as we have seen, burst and 

 emit their contents. The whole of these 

 changes occur in regular sequence, and affect 

 one or more follicles in succession. These 

 follicles, lying buried in countless numbers in 

 the substance of the ovary, supply, as it were, 

 the pabulum for the morphological changes 

 here described ; a certain number only being 

 called into full maturity, whilst the greater 

 portion of those which were originally formed 



