CHEMICAL CORRELATION OF ORGANS OF GENERATION 377 



In the female, the excision of the ovaries leads to a more or less 

 pronounced tendency toward the acquirement of masculine character- 

 istics. Very marked effects upon the male, however, are elicited if 

 the ovary be transplanted into the tissues of a castrated animal of the 

 same species. In this case not only do the secondary sexual characters 

 of the male fail to develop, but those of the female take their place, 

 even to the development of the Mammary Glands. Here, again, the 

 effect appears to be attributable rather to the interstitial elements of 

 the ovary, than to the reproductive elements. 



A remarkable instance of the converse effect, namely, suppression of 

 female characteristics by secretions from the male organs of generation, 

 is supplied by the sterility which is almost the invariable rule in the 

 females of heterosexual twins in cattle. A female of this type is known 

 to cattle-breeders as a Free-Martin. It has been ascertained by F. R. 

 Lillie that in cattle a twin pregnancy is almost always a result of the 

 fertilization of an ovum from each ovary and development begins 

 separately in each horn of the uterus. The ova, in the course of devel- 

 opment, however, meet and fuse, and the bloodvessels from each side 

 anastomose in the connecting part of the chorion, so that each embryo 

 receives part of its blood-supply from the other. Both the arterial and 

 venous circulations overlap, so that a constant interchange of blood 

 takes place. If both are males or both are females no harm results; 

 but if one is a male and the other female, the reproductive system of the 

 female is largely suppressed in its development, and certain male 

 organs even develop in the female. The effect of this is to render the 

 female incapable of reproduction. 



A recurrent cycle of changes occurs in the Ovary of the adult female 

 which results in the intermittent discharge of mature egg-cells from the 

 ovarian tissues into the Fallopian tubes leading into the cavity of the 

 uterus. The ovarian tissues contain a number of vesicles, lined with 

 epithelium and each containing an ovum, which migrate toward the 

 surface of the ovary, at the same time increasing in size. These are 

 the Graafian Follicles, which periodically rupture, discharging the ova 

 which they contain. The discharge of the egg into the Fallopian tubes 

 may or may not coincide with the period of menstruation, in fact such 

 evidence as we possess tends to show that the two processes, while 

 coinciding approximately in frequency, do not occur with strict syn- 

 chrony. The ruptured Graafian follicle, after the discharge of the 

 ovum, undergoes a series of degenerative changes which culminate in 

 the formation of the Corpora Lutea, which when mature appear as 

 spherical masses of yellowish cells, disposed in a more or less columnar 

 manner, the columns of cells radiating from the center. 



The Menstrual Fluid in ma consists of blood and shreds of cast-off 

 uterine epithelium, diluted by the secretions of the mucous glands of 

 the uterus. It contains a very high percentage of Calcium and for this 

 reason Blair Bell has suggested that it may be related phylogenetically 

 to the egg-shell of birds or of a remote common ancestor of the birds 



