The Development of the Hymen 



103 



investigations that they Avere based upon patliological material. Accord- 

 ing to Schaeffer's own statement 42 per cent of his cases showed some 

 maldevelopment of the genital tract. When we consider what we mean 

 by maldevelopment, Schaeffer's cases acquire a distinctive value of their 

 own. We mean not a different method of development, but an arrest of 

 development.* If in 43 per cent of his specimens there was arrest of 

 development in other portions of the genital tract, we have a right to 



Fig. 9. Sagittal section through the posterior end of the vagina of a human 

 embryo of 14 cm. body length (Nagel). 1, urethra; 2, vagina; 3, posterior 

 surface of the hymen ; 4, widened portion of the vagina immediately back of 

 the hymen. 



expect a rather large percentage to show an arrest of hymeneal develop- 

 ment. Now Schaeffer found in 28.8 per cent of all cases a bilamellate 

 hymen, whereas other investigators — Klein ('94), Hart ('02), Gellhorn 

 ('04) — found bilamellation but rarely or not at all. Is the inference 

 not justifiable that the additional lamella represents a membrane left 

 by some previous step of development that persisted instead of becoming 

 obliterated? But what memljrane could that be? Only the membrane 



^It is of interest in this connection that the hymen, according to Nagel, 

 appears as a membrane only in the human race. In elephants, hyenas and 

 other quadrupeds there is usually a constriction at the point of entrance of 

 vagina into sinus urogenitalis, but no true hymeneal membrane. Corre- 

 sponding to this constriction, we have at this point in man the vulvo-vaginal 

 fold. 



