TENDENCY OP SPECIES TO FOEM VAEIETIES. 61 



"We see, then, that no inferences as to varieties in a state of 

 nature can be deduced from the observation of those occurring 

 among domestic animals. The two are so much opposed to each 

 other in every circumstance of their existence, that what applies 

 to the one is almost sure not to apply to the other. Domestic 

 animals are abnormal, irregular, artificial; they are subject to 

 varieties which never occur and never can occur in a state of 

 nature : their very existence depends altogether on human care ; 

 so far are many of them removed from that just proportion of 

 faculties, that true balance of organization, by means of which 

 alone an animal left to its own resources can preserve its existence 

 and continue its race. 



The hypothesis of Lamarck — that progressive changes in species 

 have been produced by the attempts of animals to increase the 

 development of their own organs, and thus modify their structure 

 and habits — has been repeatedly and easily refuted by all writers 

 on the subject of varieties and species, and it seems to have been 

 considered that when this was done the whole question has been 

 finally settled ; but the view here developed renders such an hypo- 

 thesis quite unnecessary, by showing that similar results must be 

 produced by the action of principles constantly at work in nature. 

 The powerful retractile talons of the falcon- and the cat-tribes 

 have not been produced or increased by the volition of those 

 animals ; but among the different varieties which occurred in the 

 earlier and less highly organized forms of these groups, those 

 always survived longest which had the greatest facilities for seizing 

 their prey. Neither did the giraffe acquire its long neck by de- 

 siring to reach the foliage of the more lofty shrubs, and constantly 

 stretching its neck for the purpose, but because any varieties 

 which occurred among its antitypes with a longer neck than usual 

 at once secured a fresh range of pasture over the same ground as 

 their shorter-necJced companions, and on the first scarcity of food 

 were therely enabled to outlive them. Even the peculiar colours of 

 many animals, especially insects, so closely resembling the soil or 

 the leaves or the trunks on which they habitually reside, are ex- 

 plained on the same principle ; for though in the course of ages 

 varieties of many tints may have occurred, yet those races having 

 colours hest adapted to concealment from their enemies would inevi- 

 tably survive the longest. We have also here an acting cause to 

 account for that balance so often observed in nature, — a deficiency 

 in one set of organs always being compensated by an increased 

 development of some others— powerful wings accompanying weak 



