168 



PHYSIOLOGY 



CHAP. 



We shall see in due course what other changes it has to undergo 

 to become capable of fertilisation. 



In the protoplasm of the ovum of the rabbit, besides the 

 cavities containing the liquid material for nutrition, there exist 

 according to the researches of A. Eusso (1907) globules of a 

 lipoid nature belonging to the group of lecithins. These globules 

 are formed in the ovum rather advanced in development-, that is, 



FIG. 54. Vesicular or Graafian follicle of woman. Magnified 34 diameters. (Chiarugi.) u, ovum ; 

 cp, cumulus oophorus ; the little cavities which may be noticed represent penetrating vessels 

 from the theca interna ; e, follicular epithelium (stratum granulosum) ; e, cavity of follicle ; 

 ti, theca interna ; te, theca externa ; V, vessels. 



an ovum with a much stratified follicle, in which is beginning to 

 form the follicular cavity with its liquor follic.uli. In the less- 

 developed ova are observed only very minute granules disposed 

 in chain-like strings, and from their micro-chemical reactions 

 also lipoid. Kusso has found that these granules, as well as the 

 globules, can be produced experimentally "by injecting lecithin 

 under the skin or into the peritoneal cavity. S. Comes, a pupil 

 of Eusso, has confirmed these results in the ova of the cat, at 

 different times of its physiological activity, at the period of heat, 



