INTRODUCTION. 61 



Animals and plants, in a state of domestication, or of cultivation, 

 are subject to remarkable changes when removed from their native 

 soils; and these varieties become permanent, not reverting to the 

 original wild stock even when returned to their original localities ; 

 this he considers a well established fact. lie collected together a 

 great number of hybrids of animals and plants, and found them 

 sterile in every instance but one ; he was satisfied " that a union 

 of two species could not produce a new race, and that species were 

 the creation of God." With Prichard he considers domestication 

 of animals analogous to domestication in man, a:ul that the varieties 

 of the animal kingdom within the range of species explain the per- 

 manent varieties of man ; or, rather, that they have been produced 

 by similar causes. 



lie reviews at length the alleged instances of fertile hybrids in 

 the article of Dr. S. G. Morton, and finds no reason to change his 

 opinion as above expressed. He objects that the instances are taken 

 often from remote distances where it is impossible to verify them; 

 that the authorities quoted are either contradictory, obscure, or of 

 little scientific merit ; and the innumerable instances to the contrary 

 seem to him entirely decisive, that hybrids between different species 

 are sterile. No instance, not open to doubt, can be shown of hybrids 

 fertile for several generations, without a crossing with one of the 

 original Btocks ; many of the so-called different species, breeding 

 together, are generally believed to be mere varieties of a single 

 species, e. g., of the horse, the hog, the sheep, the dog. 



As hybrids are sterile, hybridity is a test of specific character; 

 and, as all the races of men produce with each other a fertile prog- 

 eny, they may fairly be said to be of the same species. 



The striking and permanent varieties of animals are acknowledged 

 to be the results of an organization by which the species are enabled 

 to produce varieties. Taking it for granted that we must be governed 

 by the same laws for determining species in man and animals, he 

 asks, Why do our opponents persist in calling human varieties dis- 

 tinct species? Instancing the well-known varieties of the wolf, 

 Why do naturalists admit these as mere varieties, and insist that the 

 human races are as many species? The same question is asked con- 

 cerning the horse, the cow, the sheep, the hog, the dog, domestic 

 fowls, and pigeons, in which there is the same disposition to branch 

 out into varieties from a common stock, as great as between the 

 races of men. Great variations have occurred in many Caucasian 

 nations, while wild animals, with few exceptions, have undergone 

 no change ; showing the influence of domestication. According to 

 G 



