492 NATURAL HISTORY OF MAN. 



colour distinct from that of their domesticated state, and 

 often even lose the power of barking, which some have sup- 

 posed to be an acquired quality not natural to the species. 

 The dingo of Australia and the dhole of India are instances 

 of this wilder and more primitive state. The wolfish dogs 

 which haunt the streets of Constantinople and other eastern 

 cities, furnish more familiar examples to the same effect.* 



Similar illustrations might be drawn from other domestic 

 animals, but less striking as they are less closely associated 

 with man. They all offer examples of the remarkable facts 

 to which we have alluded as a main element of the varieties 

 of race ; those, to wit, which show the transmission from 

 one generation to another of qualities or instincts artificially 

 acquired ; and which so transmitted, and maintained by use, 

 tend to become hereditary in the breed. The extent to which 

 this capacity for change proceeds the relative permanence 

 of the changes so induced the parts of structure or functions 

 most liable to them the conditions favouring or limiting 

 them these are all questions infinitely curious and largely 

 open to future research. They are connected closely, more- 

 over, with the history and theory of analogous variations in 

 Man; the manner of operation being similar, and the 

 extent and limits of deviation defined by the same general 

 laws. In these domestic species more especially, from the 

 manner in which certain acquired qualities become heredi- 

 tary in particular breeds, we obtain an index to the formation 

 of races among mankind. The enquiry, so conducted, gains 

 in value and importance when we reflect on its relation to 

 the future destinies of Man ; and see in this power of trans- 

 mission of acquired faculties, the possible element of new and 

 higher conditions of our own species. There is nothing even 

 improbable in this view, when we regard the various conditions 



* Written at Constantinople (1849) with this strange canine commonwealth 

 under my eye at the time. 



