LIFE AND ORGANISATION. 79 



In Man himself these varieties take their highest, and 

 perhaps most heterogeneous character. They are testified 

 especially in the difference of races ; a distinction so 

 strongly marked in particular cases, as to have led some 

 naturalists erroneously, as we believe to refer it to an 

 actual diversity of species. That strangely familiar friend 

 of man, the Dog, produces varieties scarcely less numerous 

 and remarkable. An eminent French naturalist has stated 

 that if we were to reckon as species the different breeds of 

 this animal, we must carry the account above fifty. The 

 extent to which such deviations may proceed and become 

 hereditary in a race, is one of the most curious enquiries in 

 natural history ; as well in reference to the authentication of 

 true species, as in connection with the subject of Animal 

 Instincts, to which it is closely related. We believe that 

 there is a natural limit to change in each particular case ; and 

 think it probable that the deviation, though differing under 

 different conditions of animal life, has already reached its 

 maximum in the animals bred and domesticated by man. 



Even here, then, the advocate for transmutation fails to 

 make good his case ; since it may almost be affirmed that 

 the particular capacity for variations in each species forms 

 in itself a specific character. These varieties or deviations 

 are not changes of species, but changes within them ; and, 

 with few and ambiguous exceptions, are confined to certain 

 limits which the law of reproduction of species strictly 

 defines. This law, in truth, comprises all the cardinal points 

 of the question. It is a natural definition put before us, and 

 so strongly marked, that the argument as to design might 

 well be made to rest on this alone. If an instance could be 

 brought of the intermixture of two species in generation 

 producing a fertile offspring, capable of breeding with simi- 

 lar hybrids, or otherwise perpetuating the physical changes 

 induced, the law would doubtless be impugned in its 



