MORPHOLOGY OF THE HUMAN UEINOGENITAL TRACT. 361: 



' We have now to try to understand the reason for this ap-i 

 parently extraordhiary development of the genital organs. It 

 seems remarkable that we should have apparently a double 

 genital tract to start with, and that each sex should, in its adult, 

 and normal condition, retain traces, so far as we know, function- 

 less, of the opposite sex. 



In the early human embryo we have a very remarkable con- 

 dition present, which I may recapitulate as follows : — 



1. A very rudimentary pi-onephros or head kidney (?). 



2. A well-marked mesonephros, or Wolftian body proper, with 



a duct. 



3. An inditlereut sexual gland developed in connection with 



the mesonephros. When this is an ovary, we get — 



4. A special female genital duct, the Milllerian retained. 



Should this gland be a testis, we get — • 



5. The AVolffian duct persisting as its vas deferens. 



This, however, does not exhaust the peculiarities, as we find 

 that when the sex is female we get parts of the mesonephros 

 and its duct normally persisting as well-marked vestiges, and 

 aiding in hymeneal and vaginal development, as I have already 

 described. When, however, the ftetus is of the male sex, we get 

 hardly any trace of the ^Milllerian duct except Morgagni's 

 hydatid ; that is to say, the adult female has more representative 

 traces of the male sex than the male sex has of the female. This 

 seems to me very remarkable, and worth investigation. 



The testis and vas deferens develop from or in connection 

 with the mesonephros, which is the strongly developed portion 

 of the Wolffian bodies. AVliat develops the Miillerian duct or 

 its Anlage ? The present current answer is that the Milllerian 

 duct develops later than the Wolffian, and apparently is de- 

 veloped by an invagination of the coelomic epithelium, i.e., of the 

 epithelium of the peritoneal cavity. As I have already hinted, 

 it may develop from the rudimentary pronephros as in some of 

 the lower mammals. At any rate, the Fallopian tube and ovary 

 are formed on a Wolffian type, as we have the funnel-shaped 

 opening and the duct passing down as uterus and vagina, 

 finally to blend with the Wolffian duct at the hymen. It has, 



