OF THE OVUM AND ITS DEVELOPMENT. 



889 



the secretion seems of itself to be a much greater tax upon the corporeal 

 powers than might have been supposed a priori: and it is a well-known 

 fact, that the highest degree of bodily vigor is inconsistent with more than a 

 very moderate indulgence in sexual intercourse; whilst nothing is more cer- 

 tain to reduce the powers, both of body and mind, than excess in this respect. 

 These principles, which are of great importance in the regulation of the 

 health, are but expressions of the general law (which prevails equally in the 

 Vegetable and in the Animal 



kingdom), that the Development FIG. 309. 



of the Individual and the Repro- 

 duction of the Species stand in an 

 inverse ratio to each other. 



3. Action of the Female. 



737. The essential part of the 

 Female Generative system, is that 

 in which the Ova are prepared; 

 the other organs are merely ac- 

 cessory, and are not to be found 

 in a large proportion of the Ani- 

 mal kingdom. In many of the 

 lower animals, the Ovarium con- 

 sists of a loose tissue containing 

 many areoke, in which the Ova 

 are formed, and from which they 

 escape by the rupture of the cell- 

 walls; in the higher animals, as 

 in the Human female, the sub- 

 stance of the Ovarium is firm and 

 compact, and consists of a nu- 

 cleated, tough, fibrous, connec- 

 tive tissue, with much inter- 

 spersed fusiform muscular tissue 

 forming what is known as the 

 stroma. It originates in a small 

 .outgrowth of the inner surface of 

 the Wolffian body, the regular 

 columnar epithelial investment of 

 which, probably derived from the 

 epiblast, and contrasting strongly 

 with the flattened epithelium of 

 the rest of the peritoneal cavity, 

 is thickened at this spot. The 

 epithelium is the rudiment of the 

 Graafian follicles and ova, whilst 

 the outgrowth is destined to form 

 the vascular stroma of the ovary. 

 As development proceeds the cells 

 of the superficial columnar, or so-called germ epithelium multiply, and single 

 cells or groups of cells, round, ovoid, or tubular, come to be inclosed in the 

 tissue of the ovary by delicate vascular processes which shoot forth from the 

 stroma. These cells constitute the primordial ova, 1 each of which is there- 



1 For the literature of the Histology of the Ovaries up to 1871, see Art. Ovary and 

 Paruvarium, by W. Waldeyer, in Strieker's Hum. and Comp. Histology, Syd. Soc. 



57 



From the ovarium of an old bitch, a, germ epithe- 

 lium ; b, ovarial tube ; c, c, young Graatr.m follicles ; d, 

 older follicle; e, discus proligi-rus, with ovum;/, epi- 

 thelium of a second ovum in the same follicle; g, fib- 

 rous tunic; h, tunica propria folliculi ; i, epithelium of 

 the follicle (membrana granulosa). 



