DR. MARTIN BARRY'S RESEARCHES IN EMBRYOLOGY. 319 



Isolated Spots in the Graafian Vesicle. 



59. These appear to be of two kinds, but are really the same, — in the one case 

 seen single, in the other grouped. Plate VIII. fig. 66. g*, presents the appearance of 

 these objects in the one state, and Plate V. fig. 26^. their appearance in the other. 

 Each of these spots I find to consist of one of the peculiar granules of the Graafian 

 vesicle, having a peripheral accumulation consisting of oil-like globules-f . The pe- 

 culiar granules are transparent and comparatively large ; the oil-like globules appear 

 dark in their circumference by reason of a very different refracting power from that 

 of the suspending fluid ; they are also of a minuteness quite immeasurable. When 

 these objects are in small number, they present the appearance shown in Plate VIII. 

 fig. 66. g*. ; and when in very large number, that presented in Plate V. fig. 26 J. J. 



Disappearance of Ova, and Formation of others. 



60. I have very often met with ova in the state represented in Plate VIII. fig. 6/, 

 which was observed in a Rabbit of about ten weeks old. The chorion (/*) has be- 

 come thin, distended, and of an elliptic form. It measured in this instance one-fifth 

 of a Paris line in length §. The yelk {d) is nearly black, consisting chiefly of gra- 

 nules of extreme minuteness, with some oil-like globules and a fluid. Its membrane, 

 if still existing, is not distinguishable from the chorion ; and indeed the chorion itself 

 is scarcely to be distinguished from the yelk. The germinal vesicle (t) is generally 

 situated at one end of the ovum, as in this instance, — appears more or less flattened or 

 collapsed, — and is much enlarg-ed. It measured in this case -\\h of a line in length. 

 The germinal spot {h) also was enlarged, having measured in this instance -^t\\ of a 

 line in length, for it was somewhat elliptical. Its contour is not well marked. The 

 colour of the Graafian vesicle, with such a condition of its ovum, is often tinged with 

 yellow. In young Rabbits this state of the ovum has presented itself so frequently, 

 that I have observed several in the same field of view. I apprehend it to denote a 

 stage in the absorption of ova ; which on the other hand appear to be continually re- 

 placed by new formations ||. 



t Among the oil-like globules there are sometimes visible a few minute opake granules. 



X Spots which I suppose to represent the first of the two states now described, have been figured in Bekx- 

 hakdt's Dissertation, Symbolae, &c., fig. xvii. ; but the author's description of them does not quite accord 

 with that which I have given. 



§ = -sV of an English inch. 



II In a future paper it will be shown that.pos^ coitum, many ova are absorbed. In Plate VI. figs. 44. and 46. 

 are seen two ova in which absorption is incipient, as indicated by a loosening of the granules, and consequent 

 enlargement of the tunica granulosa (g^), — by the more globular form of some of these granules (9.), — and by 

 liquefaction of the yelk around the germinal vesicle. 



