RECAPITULATION AND CONCLUSION. 65 



it true that all human crossings are eugenesic ? To upset the 

 syllogism of the monogenists, and to deprive their system of any 

 scientific base, it might bo sufficient that the first of the above 

 questions should be answered in the negative. The system 

 would then become what it was before it came in contact with 

 science, namely, a belief more or less respectable, founded 

 upon a sentiment or a dogma. But if the second question were 

 also negatived, and it could be demonstrated that all human 

 crossings are not eugenesic, then not merely the syllogism, 

 but the whole doctrine of the monogenists would crumble to 

 pieces. The doctrine would then not merely be extra- scientific, 

 but anti-scientific ; it being positive that two groups of ani- 

 mals, so different as to be incapable of fusion by generation, 

 do not belong to the same species. This is an incontestable 

 and uncontested truth. 



We were thus led to examine successively the two funda- 

 mental propositions serving as a base to the unitarian doc- 

 trine, for which purpose a series of researches were requisite. 



We have, in the first place, investigated the results of cer- 

 tain crossings between animals of incontestably different spe- 

 cies, such as dogs and wolves, goats and sheep, camels and 

 dromedaries, hares and rabbits, etc. ; and we have demonstrated 

 that these crossings "produce eugenesic mongrels, that is to say, 

 perfectly and indefinitely prolific between themselves. 



It is thus not true that all animals capable of producing an 

 eugenesic progeny are of the same species; and even if all 

 human intermixtures were eugenesic, as is generally believed, 

 we could not infer from this the unity of the human species. 

 The monogenists are thus deprived of their principal basis and 

 their sole scientific argument. 



It was, however, necessary to inquire, whether this popular 

 axiom, that all human crossings are eugenesic, was a demon- 

 strated truth or a lightly accepted hypothesis, without any 

 verification or control ? Such has been the object of our 

 second series of investigations. 



We recognised at the outset that the monogenists, consider- 

 ing their axiom as self-evident, have made no efforts to esta- 

 blish its correctness, so that, strictly speaking, we might have 



f 



