356 



It may be added, that the presence ofnormal female parts, which 

 performed the function of menstruation, renders it highly proba- 

 ble that this individual was susceptible of impregnation. On the 

 other hand, it is improbable that the testicles ever performed 

 iheir true function, and so this individual was, physiologically, 

 only a female. Were this not so, and had the testicles secreted 

 spermatic particles, this person must almost inevitably have be- 

 come self-impregnated, as the sperm could scarcely avoid passing 

 into the vaginal tube. 



But, interesting as this case is, as a very rare form of monstros- 

 ity, it is much more so from the anatomical and embryological 

 points it involves. These are so important, that I shall improve 

 this occasion to refer to them somewhat at length. 



What explanation, derived from embryological data, shall be 

 put upon monstrosities, with duplicity of organs or parts? Two 

 principal hypotheses have been, and still are, maintained by dif- 

 ferent observers. One of these is, that they are invariably refer- 

 able to the more or less complete fusion of two germs ; the whole 

 of one of these germs proving entirely abortive, excepting that 

 portion corresponding to the duplex organ. The other hypothe- 

 sis is, that it is due to a segmentation of one germ at the part or 

 parts, where the duplicity occurs. 



This question is so deeply connected with the whole history of 

 development, that its proper consideration cannot be entertained 

 without a considerable knowledge of embryology ; and without 

 this, any person would be liable to grave errors, it matters not 

 how many and varied were his specimens for examination. 



The laws of development, expressed as they are through type- 

 forms, are the same everywhere in the animal kingdom. They 

 are invariable, and what is found in the lowest forms of a certain 

 type of animals, may be predicted with certainty of the highest 

 forms of the same. 



Now the doctrine of the coalescence of the two distinct germs 

 for the formation of monsters, is open to the objection that it goes 

 too far, and proves too much ; for, if accepted in such cases of 

 complete duplicity as the Siamese twins and Hungarian women, 

 it must also be accepted in the simplest forms, such as a super- 

 numerary finger or toe ; and in these most simple cases, it is 



