BY F. P. SANDES. 371 



The Primordial Follicle. 



Before entering upon the consideration of the primordial 

 follicle itself, it will be necessary for the sake of completeness to 

 describe shortly the appearance of the ovary macroscopically and 

 microscopically. The organ in the period of its greatest size is 

 of ovoid shape, measuring on an average 6 mm. by 5 mm. in its 

 diameters. When the follicles are ripe they show as projecting 

 bosses upon the surface. After their rupture the " stigma " 

 can be seen, and soon also the corpus luteum, standing out 

 as a yellowish-wdiite structure against the general background 

 of the ovary. In section, the organ shows the usual fibrous 

 connective tissue stroma, containing ova in various stages of 

 development. Near the periphery of the ovarj^, the fibrous tissue 

 is condensed, and the (Surface of the organ is coated by a layer of 

 cubical epithelium. A similar condensation of connective tissue 

 is found round the larger primordial follicles and the more fully 

 developed Graafian follicles. The smaller vessels are placed in 

 these condensed areas of connective tissue, whilst centrally and 

 elsewhere are found the larger vessels of the ovar}', surrounded 

 by a more rarefied stroma substance. Generally speaking, the 

 3''oung primordial ova lie in the peripheral condensed ovarian 

 stroma, a little distance below the surface epithelium, and in the 

 angles between the larger ova and follicles, where they approach 

 the surface; whilst the older ova are not localised to any particular 

 part of the ovar}^ many being superficial and man}^ buried some 

 distance beneath the surface (see fig. 2). 



The ovum in its earliest recognizable stage (primordial ovum, 

 see fig. 1) appears as a rounded cell placed in the condensed peri- 

 pheral ovarian stroma, just beneath the epithelium of the surface. 

 It is larger than the surrounding cells, and contains a finely 

 granular cytoplasm v/hich stains less deeply with hagmatoxylin 

 than the neighbouring connective tissue elements. It is clearly 

 distinguishable from the surrounding cells, and possesses a nucleus 

 with a nucleolus, the nuclear chromatin being arranged periphe- 

 rally near the nuclear membrane. At first there does not appear 



