304 John Bachman . 



which Audubon has made to his name, attest both 

 the variety and accuracy of his information in several 

 departments of Natural History. More recently the 

 preparation of the beautiful work on "The Quadru- 

 peds of North America/' has established his reputa- 

 tion as an authority upon all subjects relating to the 

 Zoology of this continent. 



Dr. Bachman's present work shows throughout 

 that he has been long engaged in careful and phil- 

 osophical investigation of topics in various depart- 

 ments of Natural History, which bear upon the 

 question of the nature of a species. 

 Aiming to settle the question of the unity of man- 

 kind upon purely scientific grounds, Dr. Bachman 

 discusses it in almost every aspect ; and varied as 

 these aspects are, there is scarcely one of them on 

 which he does not cast some new light. The ques- 

 tion of the possibility of hybrid races of animals, is 

 examined with great thoroughness, and even min- 

 uteness of detail; the question of varieties among 

 the domesticated animals, is discussed with the most 

 complete command of facts of the highest signifi- 

 cance. The diffusion of species of animals and 

 plants is treated with the same learned accuracy ; 

 and every one of these discussions is enriched with 

 statements of facts, observations, and experiments, 

 many of which are new, original, and decisive. The 

 bearing of these facts is then shown upon the ques- 

 tions which relate to the origin and dispersion of 

 mankind, with a result which is striking and happy 

 beyond all expectation. On the whole, the work is 

 so complete that this branch of the general subject, 

 hitherto the most neglected, is now placed in the 

 clearest light ; and Dr. Bachman's conclusion of the 

 derivation of all mankind from a single pair, is 

 altogether beyond the reach of any objection upon 

 grounds of Natural History. No work upon the 



