200 DR. JAMES FOULIS. 



ordinary germ epithelial corpuscles all round the ovary, we 

 find individuals standing forth prominently and conspicuous 

 by their size and the size of their nuclei, similar to those 

 bodies we described as conspicuous among the corpuscles of 

 the germ epithelium in the kitten's ovary. Such have been 

 termed primordial ova. On comparing these with the 

 smaller round corpuscles, and these latter with the ordinary 

 germ epithelial corpuscles, it is easy to see that they are 

 germ epithelial corpuscles in a far advanced state of develop- 

 ment. In the progress of growth the nucleus of the 

 ordinary germ epithelial corpuscle first swells out and en- 

 larges, becoming oval, then spherical, and around it is 

 gradually produced that protoplasm which assumes such 

 dimensions in the primordial ova. In contact with these 

 primordial ova we often see small fusiform corpuscles, and as 

 in the case of the kitten's ovary, some of them appear to 

 have grown up among the germ epithelial corpuscles from 

 the stratum of young connective tissue on which the germ 

 epithelium rests. 



It is a fact of great interest, that as tlie germ epithelial 

 corpuscle becomes a primordial ovum, the nucleus which at 

 first appears ill defined and semi-solid, and is surrounded by 

 a comparatively small quantity of protoplasm, now shows a 

 remarkably clear definition, and at last appears as a spherical 

 vesicular body with a fine double-contoured wall, and within 

 it one or two nucleoli are usually seen. The nucleus of each 

 germ epithelial corpuscle becomes the germinal vesicle of 

 the primordial ovum, and the nucleolus corresponds to the 

 germinal spot. 



The ordinary germ epithialial corpuscles measure in their 

 longest diameter about -oVo^'^ of an inch, and in their 

 shortest -j-^Voth of an inch, but both these measurements 

 vary considerably. 



On referring to Waldeyer's work " Eierstock und Ei," 

 plate ii, figs. 9, 11, 13, I find that he represents the germ 

 epithelial corpuscles as little bodies in which the nuclei 

 are comparatively small, while the protoplasm round these is 

 in all cases very extensive. This is not in accordance with 

 my observations. An examination of the ovaries of 

 numerous foetal and newly born animals clearly shows that 

 in each ordinary germ epithelial corpuscle the nucleus con- 

 stitutes by far the greater part of the corpuscle, the proto- 

 plasm around it being in the form of a fine film. In the 

 primordial ova, however, the enlarged nucleus has around it 

 a correspondingly large quantity of protoplasm, and then 



