FEMALE OKGANS OF GENERATION. 



861 



from below, which enclose little collections of cells. By both of these processes, little 

 cavities are formed, which contain a number of cells. In each of these cavities, we 

 observe a single, large, rounded cell, with a large nucleus, this cell being a primordial 

 ovum ; and, in addition, we have in the same cavity, other cells, which are the cells of 

 the Graafian follicle. The exact nature of the processes we have just described has been 

 studied in the fowl, but it is probable that the same kind of development occurs in mam- 

 malia and in the human female. 



From birth until just before the age of puberty, the cortical substance of the ovary 

 contains thousands of what are termed primordial follicles, enclosing the primordial ova; 

 and it is probable that, after the ovaries are fully developed at birth, no additional ova 

 or Graafian follicles make their appearance. The prevailing idea is, indeed, that the 

 great majority of these never arrive at maturity, and that they undergo atrophy at vari- 



FIG. Ml. Portion of a sagittal section, of tlie, ovary of an old bitch (Waldeyer.) 



a, ovarian epithelium; 5, &, ovarian tubes; c, c, younger follicles; d, older follicle; e, discus proligerus, with the 

 ovum ; /; epithelium of a second ovum in the same follicle ; g, fibrous coat of the follicle ; ft, proper coat of the 

 follicle; *, epithelium of the follicle (membrana granulosa) ; k, collapsed, atrophied follicle ; , blood-vessels ; m, ?, 

 cell-tubes of the parovarium, divided longitudinally and transversely ; y, tubular depression of the ovarian epi- 

 thelium in the tissue of the ovary ; 2, beginning of the ovarian epithelium close to the lower border of the ovary. 



ous stages of their development. According to the table of measurements given by Wal- 

 deyer, the primordial follicles of the human embryo, at the seventh month, are from 

 about 3-^-5- to 2^5 of an inch in diameter, and the primordial ova, from -j-sV^ to y^Vrr f an 

 inch. In the adult, the smallest follicles measure from about ^|^ to -^ of an inch, and 



