148 GENITAL ORGANS. 



Stroma. The most important peculiarity to notice is the 

 extraordinary frequency of bundles of spindle-shaped cells 

 which run across each other in various directions. Their claim 

 to be regarded as muscular or connective tissue cells is still 

 open to question. Both in the sow and bitch, there are 

 bundles of unstriped muscular fibres, which, along with blood- 

 vessels, run from the medullary part into regions in which 

 large follicles are to be met with, and form an investment of 

 the follicular wall. There are, however, many bundles in the 

 cortical substance which present no such definite characters. 

 But in the ovary of the guineapig, muscular bundles can be 

 distinctly recognized even in the stroma of the cortex. 



Graafian Follicles. The structure of these follicles can 

 be made out completely in the preparations above referred to. 

 For the study of their development, human fetal ovaries and 

 those of the dog must be used. In the former, it is seen that 

 from that part of the surface which is covered with germinal 

 epithelium, blind tubes are sunk to various depths and in 

 various directions. These tubes are lined with an epithelium, 

 which is continuous with that of the surface, and identical 

 with it. It can further be made out that certain individual 

 elements of this epithelium have a special character, being 

 more readily stained with carmine, and that they are larger 

 than the others. Between these and ovules all transitions 

 can be observed. By the segmentation of a single tube into 

 several closed vesicles, Graafian follicles are formed, each of 

 which is lined with a layer of epithelium, and contains one or 

 two nucleated ovules, so that both stand in a definite develop- 

 mental relation to the germinal epithelium. These facts may 

 be demonstrated equall} 7 well in the ovary of the bitch ; a zone 

 of tissue exists under the germinal epithelium in which closed 

 tubes are met with, which run in very various directions. 

 Many of these look as if they were connected with each other 

 so as to form a network. Deeper, there is a zone in which 

 separate follicles exist. 



Ovum and Discus Proligerus. The ovum itself and 

 the cells of the Discus proligerus may be studied in fresh 

 ovaries. The contents of a large Graafian vesicle of the 

 rabbit's or guineapig's ovary are discharged on to an object- 

 glass for the purpose. They can also be well seen in the pre- 

 parations above described. 



Fallopian Tubes, Uterus, Vagina, and External 

 Organs. These may be best studied in sections of organs 

 hardened in chromic acid the methods recommended in Part 

 I. being employed for the study of the several tissues of 

 which they consist. Some special remarks are, however, 

 necessary relating to the glands of the uterus. They can be 

 best demonstrated in the cornua uteri of bitches or cats which 



