FUNDAMENTAL RELATIONS OF ANIMALS 19 



no structural difference between the herrings of the Arctic, or those 

 of the Temperate zone, or those of the Tropics, or those of the An- 

 tarctic regions; there are not any more between the foxes and wolves 

 of the most distant parts of the globe.-** Moreover, if there were any, 

 and the specific differences existing between them were insisted 

 upon, could any relation between these differences and the cosmic 

 influences under which they live be pointed out, which would at the 

 same time account for the independence of their structure in gen- 

 eral? Or, in other ^vords, how could it be assumed that while these 

 causes would produce specific differences, they would at the same 

 time produce generic identity, family identity, ordinal identity, class 

 identity, typical identity? Identity in everything that is truly impor- 

 tant, high, and complicated in the structure of animals, produced by 

 the most diversified influences, while at the same time these extreme 

 physical differences, considered as the cause of the existence of these 

 animals, would produce diversity in secondary relations only! What 

 logic! 



Does not all this show, on the contrary, that organized beings ex- 

 hibit the most astonishing independence of the physical causes under 

 which they live; an independence so great that it can only be under- 

 stood as the result of a power governing these physical causes as well 

 as the existence of animals and plants, and bringing all into harmo- 

 nious relations by adaptations which never can be considered as cause 

 and effect? 



When naturalists have investigated the influence of physical causes 

 upon living beings, they have constantly overlooked the fact that the 

 features which are thus modified are only of secondary importance 

 in the life of animals and plants, and that neither the plan of their 

 structure nor the various complications of that structure are ever 

 affected by such influences. What, indeed, are the parts of the body 

 which are in any way affected by external influences? Chiefly those 

 which are in immediate contact with the external world, such as the 

 skin, and in the skin chiefly its outer layers, its color, the thickness 

 of the fur, the color of the hair, the feathers, and the scales; then the 

 size of the body and its weight, as far as it is dependent on the qual- 

 ity and quantity of the food; the thickness of the shell of Mollusks, 



^Innumerable other examples might be quoted which will readily present them- 

 selves to professional naturalists; those mentioned above may suffice for my argument. 



