106 Fred. J. Taussig 



sue. There are really only the two folds, just as in my sections, the one 

 vulvo-vaginal, the other vaginal; the former a thin septum, the latter a 

 thick membrane. In the absence of contradictory evidence, I feel justi- 

 fied in considering Klein's case as rather supporting than opposing 

 my views. 



The character of the epithelial covering also gives support to the 

 vaginal theory. Klein lays stress on the marked differences between the 

 vaginal and the vulvar epithelium. Gellhorn's ('04) microscopic sec- 

 tions of seven hymens at various stages of fetal development show that 

 vaginal epithelium lines both sides of the hymen. 



The direction of the hymeneal connective tissue fibres has been em- 

 phasized by Gellhorn ('0-i) as being of considerable importance. Even 

 in fetuses at full term they could be seen running parallel and con- 

 tinuous with the vaginal connective tissue fibres. From the vulva no 

 fibres enter into its composition. 



I am well aware that the evidence of the serial sections in these five 

 embryos is insufficient to firmly establish my contentions. Further 

 investigations are necessary. Unfortunately, the material in a fresh 

 state is not easily collected. Progress in this question can, however, 

 only be made by the study of serial microscopic sections of the lower 

 genital tract in fetuses of 18-30 cms. length. 



Evidence of the sort that has heretofore been employed to support 

 theories of hymeneal development, even if absolutely contradictory, 

 cannot invalidate the views expressed in this paper. It would require 

 evidence of the same character, serial sections of a number of embryos, 

 to do this. Until such evidence is at hand, therefore, we must consider 

 the hymen as a vaginal structure formed in the fifth month of fetal life 

 by connective tissue proliferation directly anterior to the point where 

 the vagina enters into the urogenital sinus. 



In conclusion, I wish to thank Dr. E. J. Terry, Professor of Anatomy 

 at Washington University, for assistance in getting material for this 

 work and many helpful suggestions; also Dr. H. P. Wells for his excel- 

 lent micro-photographs. 



LITERATURE. 



AcKEEEN, F. VAX. 1888. Beitriige zur Entwickelungsgescbichte der weib- 

 lichen Sexual-organe des ^Mensclien. Zeitschrift f. Wissen. Zool., Vol. 

 XLVIII. 



Bayer, H. 190.3. Entwickeluiigsgeschichte des weiblichen Genitalapparates. 

 Vorlesungeu iiber Allg. Geburtsbilfe, Vol. I, Part 1, Strassburg. 



