PHYSIOLOGICAL PROPERTIES OF GONADS 139 



of various sizes within the graft, but also by the fact that the 

 cells of the follicles show numerous mitotic figures. This, as 

 well as the very evident changes of other kinds, clearly indicates 

 that the sections of tissue do not merely represent the type of 

 structures present within the tissue at the time of transplantation, 

 but show that there have been changes going on in the ovarian 

 tissue during its residence within the male for several months, 

 and that these changes are for a large part, essentially similar 

 to those changes that would have ensued had the gland remained 

 undisturbed. How long the ovary might have remained in this 

 abnormal environment is of course unknown, but for the eight 

 and one-half months' time it remained in the male animal there 

 is little evidence of degeneration of the tissue as a whole or of 

 resorption of the graft. 



Histologically, the substance of the grafts consists of ovarian 

 tissue within which are preserved all stages of the Graafian 

 folhcles. In the majority of the grafts primordial folhcles (a 

 primordial ovocyte surrounded by a single layer of follicular 

 cells) are relatively abundant, but in some the younger folhcles, 

 though present, are not the predominating feature. Figures 3, 4, 

 5, and 6 represent a few of the progressive stages in the develop- 

 ment of a follicle, and all except figure 6 are from an ovarian 

 graft taken from the male (49 A) 230 days after the original 

 operation. Each of the stages and many others are represented 

 not only by this graft, but also by practically every graft in 

 which the ovarian tissue is retained, and it does not allow of the 

 least doubt that the production of mature folhcles proceeds 

 under these abnormal conditions. In figure 6 the ovum, enclosed 

 by its discus proligerus, has just extruded a polar body in the 

 maturation stage; it is supposed that this is the first polar body. 

 Beyond the maturation stage, however, the further normal 

 activity of the follicle is interrupted, and instead of ovulation 

 and corpus luteum formation, the follicles undergo atresia. 



In the normal female the ovum forms its second maturation 

 spindle while in the follicle and remains in this condition until 

 ovulation, but it is well known that those ova which are retained 

 by accident within the follicular cavity at the time of ovulation, 



