520 OVUM IN THE OVARY. 



mixture with acid mucus of the vagina. So long as these periods con- 

 tinue, the individual possesses the reproductive power, the first appear- 

 ance of the catamenia indicating the capacity for conception, and the dis- 

 appearance, at about the 45th year, its end. During gestation the cata- 

 menia are suspended, and, indeed, it is this event which is usually taken 

 as the indication that conception has occurred. 



The periodical occurrence of this discharge in the human female, though 

 more frequent, is essentially the same as the periodically occurring heat 

 of other animals, which is also attended with a sero-sanguinolent dis- 

 charge. In other respects, likewise, the analogy is maintained, for in 

 those animals, the appearance of this discharge and its attendant phe- 

 nomena constituting an indication of a simultaneous capacity for con- 

 ception, in women the same thing holds good, conception occurring in 

 them at the time of the close of the menstrual discharge. 



I. Ovum in the Ovary. 



The ovary is the organism in which the ova are prepared, these bodies 

 arising in the following way : 



In the stroma of the ovary there occur at a time ten, twenty, or many 

 Production more cells, which have received the designation of Graafian ves- 

 of ova. j c i es or O visacs. These originate in the interior of the ovary, 

 and, as they become perfected, pass to its surface, presenting themselves 

 thereupon as prominences which are covered over exteriorly with peri- 

 toneum. Each of these vesicles has a membranous envelope connecting 

 it with the substance of the ovary exteriorly, and covered interiorly with 

 a layer of nucleated cells, designated membrana granulosa. It is filled 

 with a fluid in which multitudes of granules float, and in its centre is the 

 ovule. This, as it becomes mature, is pushed up toward the surface of 

 the ovisac by an accumulation of liquid in the lower part thereof, and 

 is so brought into close relation with the membrana granulosa at the 

 place where it is upon the surface of the ovary. At this point there col- 

 lects on the ovum a zone of granules, to which the designation of discus 

 proligerus is given. 



Fig. 248, transverse section through the ovary of a woman dead in 

 the fifth month of pregnancy : <z, Graafian follicle of inferior, and, , of 

 superior surface ; c, peritoneal lamella of ligamentum latum, continued 

 Upon the ovary, and coalescing with, d, the tunica albuginea : in the in- 

 terior two corpora albicantia (old corpora lutea) are visible; , stroma of 

 the ovary. (Kolliker.) 



Fig. 249, section of the Graafian vesicle : 1, stroma of ovary, with 

 blood-vessels ; 2, peritoneum ; 3 and 5, layers of the external coat of the 

 Graafian vesicle ; 4, membrana granulosa ; 6, fluid of the vesicle ; 7, gran- 

 ular zone, or discus proligerus ; 8, the ovum. (Von Bar.) 



