FECUNDITY. 135 



Dr. Simpson, in his valuable paper, from which 

 we have already quoted, says : "As to the cause of 

 the malformation and consequent infecundity of the 

 organs of generation in the free-martin cow, we will 

 not venture to offer any conjecture in explanation of 

 it. 



" It appears to be one of the strangest facts in the 

 whole range of teratological science, that the twin 

 existence in utero of a male along with a female 

 should entail upon the latter so great a degree of 

 malformation in its sexual organs, and in its sexual 

 organs only. The circumstance becomes only the 

 more inexplicable when we consider this physiologi- 

 cal law to be confined principally, or entirely, to the 

 cow, and certainly not to hold with regard to sheep, 

 or perhaps any other animal. The curiosity of the 

 fact also becomes heightened and increased when we 

 recollect that when the cow or any other uniparous 

 animal has twins, both of the same sex, as two males 

 or two females, these animals are always both perfect- 

 ly formed in their sexual organization, and both ca- 

 pable of propagating. In the course of making the 

 preceding inquiries after females born co-twins with 

 males in the human subject, we have had a very great 

 number of cases of purely female and purely male 

 twins mentioned to us, who had grown up and be- 

 come married ; and in only two or three instances, at 

 most, have we heard of an unproductive marriage 

 among such persons. Further, we may in conclusion 

 remark that, among the long list of individual cases 

 of hermaphroditism in the human subject that we 

 have had occasion to cite, we find only one instance 



