104 Fred. J. Taussig 



left at the point where the vaginal bulbus breaks into the sinus urogen- 

 italis. It is this vulvo-vaginal fold, I believe, so clearly to be seen in 

 my specimens, that in Schaeifer's cases persisted to a later date in a 

 number of instances and gave the appearance of an additional fold 

 of the hymen. This assumption is further supported by the following 

 table in Schaeffer's work: 



Number of 

 Length of Fetus. Specimens. 



16-25 cms 9 



26-30 cms 8 



31-35 cms 26 



36-40 cms 41 



41-45 cms 58 



Over 45 cms 28 



The steady decrease in the percentage of l)ilamellate hymen as the 

 state of development increases is very striking and certainly would incline 

 one to the belief that the bilamellate hymen represents a more primitive 

 stage of development. 



So much for the clinical and gross anatomical evidence on this subject. 

 Coming now to the microscopic investigations, we must put aside as of 

 secondary value all those ^jased on fetuses previous to the fifth month of 

 development, at which time the hymen, according to the consensus of 

 opinion, first makes its appearance.^ This would include ISTagel's ('97) 

 sections of a 14 cm. fetus (Fig. 9) which gives pictures of a vulvo- 

 vaginal septum similar to that found in my Embryos 1 and 2. In the 

 series of sagittal sections of a 26 cm. fetus studied by Klein ('94) (Fig. 

 10) we have valuable evidence. A comparison of his illustrations with 

 mine are very interesting. He finds a vulvo-vaginal fold that he inter- 

 prets as the hymen at the point of junction of vagina and urogenital 

 sinus. Just anterior to this fold and extending from both ventral and 

 dorsal walls is a fold considerably thicker than the so-called hymen. 

 Klein's explanation of this fold is that it is a column of vaginal tissue 

 such as we occasionally find in hymen columnatus. Neither in his pic- 

 tures nor in his description has Klein proven this, and a priori it is 



"This excludes the work of Berry Hart ('02), who argues from the serial 

 sections of two embryos of three months development that the hymen is 

 formed fi-oni the Wolffian ducts. Webster ("98) has clearly pointed out the 

 fallacy of his conclusions. 



