to form Varieties, 



6307 



near the type of the original wild stock, or become altogether 

 extinct. 



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 ab- 

 normal, 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 w^hich alone an animal left to its own resources can pre- 

 serve 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 develop- 

 ment 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 hypothesis quite unnecessary, by show- 

 ing that similar results must be produced by the action of principles 

 constantly at work in nature. The powerful retractile talons of the fal- 

 con and the cat tribes have not been produced or increased by the voli- 

 tion of those animals ; but among the different varieties which occurred 

 in the earlier and less highly organized forms of these groups, tJiose 

 alivays survived longest which had the greatest facilities for seizing 

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

 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 anti-types with a longer neck than usual at once secured a 

 fresh range of pasture over the same ground as their shorter-necked 

 companions, and on the first scarcity of food were thereby 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 explained on the same principle ; 

 for though in the course of ages varieties of many tints may have 

 occurred, yet those races having colours best adapted to concealment 

 from their enemies would inevitably survive the longest. We \m\e 

 also here an acting cause to account for that balance so often observed 

 in nature, — a deficiency in one set of organs always being compen- 

 sated by an increased development of some others — powerful wings 



