DEVELOPMENT OF THE OVUM. 14Y 



DEVELOPMENT OF THE OVUM. 



As has been previously shown, the ovary is covered with epithe- 

 lium; and singular as it may appear, the fifty thousand Graafian fol- 

 licles, which it is estimated are developed during the life of the 

 human female, have their origin in these cells. 



During foetal life, this surface epithelium undergoes a very rapid 

 proliferation, and chains of cells are imbedded in the stroma of the 

 ovary. A little later in the development, separate portions or links 

 of these chains are cut off by the ingrowth of the stroma. The little 

 groups of cells thus isolated become each a Graafian follicle. 



Scattered among the columnar cells, larger, more nearly spherical 

 cells are also found, the primordial ova. These are also imbedded in 

 the substance, and one at least will always be found among the 

 minute collections of cells which have been isolated. 



In the process of development, each group of cells becomes a Graa- 

 fian follicle with its contained ovum, the columnar cells forming the 

 wall proper, and the primordial cell the ovum with its vesicle and 

 germinal dot. 



PEACTICAL DEMONSTRATION. 



The ovary from a still-born babe is to be removed with the scissors, 

 exercising the utmost care that the surface be not touched. Place 

 immediately in strong alcohol, and in twenty-four hours it will be fit 

 for cutting. Cut extremely thin sections at right angles to the free 

 surface and including the same. Stain with hsema. and eosin. 

 Mount in dammar. 



OYARY OF HUMAN FCETUS OF EIGHT MONTHS. 



(Fig. 99.) 



OBSERVE: 

 (L.) 



1. The free surface. (Note the occasional depressions which 

 mark the involution of epithelia.) 



2. The layers. (Note the absence of demonstrable tunica albu- 

 ginea and the great area occupied by the cortex. The vessels of the 

 central portions are unlike the ovary of mature life; large, not 

 numerous, and thin-walled. ) 



