1990 



Iir.MAN ANATOMY. 



sesses a diameter of from 



initiation into a peripheral p 

 within the former 



are 



to * 



FIG. 1688. 



r W- liberated from the Graafian follicle pos- 

 The human ovum when about to be =~ //Jtf> exhibits differ . 



zone. According 

 gH ht Superfid 3 

 ^ ap arently 



homogeneous and free from 

 yolk-particles, and a finely 

 granular zone containing mi- 

 nute and scattered deutoplas- 

 mic granules. The dark or 

 central deutoplasmic zone is 

 conspicuous on account of 

 the irregular refraction of the 

 enclosed yolk-particles that 

 represent the important nutri- 

 tive materials for the embryo 

 contained in the eggs of birds 

 and reptiles, but which in the 

 mammalian ovum, especially 

 in that of man, have been for 

 the most part lost during the 

 evolution of the higher types. 

 Beyond a slight condensation 

 of the surface, the presence 

 of a distinct cell-wall, or vt- 

 telline membrane, in the mam- 

 malian ovum is doubtful. In 

 the fresh condition the egg- 

 cytoplasm is usually closely 

 applied to the zona pellucida 

 (Ebner), the narrow inter- 



vening cleft that is sometimes seen being the peritritelline space. Embedded within the 



deotOpiwnic zone, and always eccentrically placed, lies the spherical germinal reside, 



as the egg-nucleus is termed. The vesicle measures from .O3O-.O45 mm. in diameter, 



is bounded by a sharply denned double-contoured nuclear membrane, and contains 



tint germinal spot or nucleolus (from .004-. 008 mm.) and the nuclear reticulum. 



Corpus Luteum. The causes leading to the final rupture of the Graafian 



follicle are still uncertainly known, although in the light of later researches the older 

 , attributing the burst ing of the ripe vesicle to mechan- 



ic. d ovenlistention induced by accumulation of the liquor 



folliculi, is inadequate. According to Nagel, when the 



follicle approaches maturity the inner layer of the theca 



becomes the seat of great activity. The blood-vessels in- 



crease in size and number and the cells undergo not only 

 ion, but extraordinary growth, the enlarged 



elements becoming filled with a peculiar yellowish sub- 



stance and ttan-iormcd into ////,-/// t -flls. 



In consequent T of this activity, the formerly smooth 



theca becomes thickened and \\a\\ and projects into the 

 Ilicle as vascular papillae and ridges. The 

 -nt thus effected gradually forces the contents 

 thl ls the surface and that part of the dis- 



,.!.-d t'olli.ul.ir wall possessing least vitality and resist- 



Almott mat 



KTTiniTi 



KIII tmimlfd by 



taken from fresh ovary-. Ovum, with 



iti Ic'l by < Irar zona pellucida, which is 

 :ir c|>iilirlimn. 300. (Waldeyer.) 



FIG. 1689. 





Ligament 

 ni" ovary 



Ovary has been laid opi-n by 

 longitudinal im-isii>!i. exposing 

 follicles and corpus luteum. 



until, liiully. rupture takes ]>la. ,-. Coincidently with 

 tn ' - ' tin- lt-in cells, the follicular epithelium 



hange which results in the breaking down of the cumulus and the 



.v.,m encircled with the cells of the discus proligerus, into the 



jc Uhen rupture of the follicle occurs, the expulsion of the 



ul cells immediately surrounding it is followed by hemorrhage 



