42 THE FUNCTIONS OK LIFE. 



conversant with the details of comparative anatomy, 

 a knowledge of the general structure and habits of 

 that animal, though all other traces of its existence 

 may have been swept away, amidst the primeval 

 revoUitions of the globe.* 



Not only does this tendency to conform to parti- 

 cular types obtain in all organic formations, but 

 further inquiry leads to the conclusion that the de- 

 viations from these standard forms, far from being- 

 arbitrary, are themselves referable to definite laws. 

 The regulating principle of the variations is subor- 

 dinate to higher views, and has reference to the 

 respective objects and destination of each particular 

 species in the general system of created beings. 

 Nature, as far as we can discern, appears, in con- 

 formity with these intentions, first to have laid down 

 certain great plans of functions to which she has 

 adapted the structure of the organs ; the minor 

 objects and more subordinate functions being ac- 

 commodated to this general design. Hence arises 

 the necessary and reciprocal dependence of each 

 organ and of each function on every other; and hence 

 are deduced what have been termed the laws of the 

 co-existence of organic forms. By attention to these 

 laws we may often explain how each variation that 

 is observed in any one organ, common to a natural 

 group of animals, entails certain necessary and cor- 

 responding variations in other parts, and extends its 

 influence in modifying, in a greater or less degree, 

 the whole fabric. It is in comparative anatomy as 

 in mechanics, where any alteration made in the 



* See Cuvier's " Discours sur les revolutions de la surface du 

 globe," p. 47, prelixed to the first volume of his " Ossemcns Fos- 

 siles." 



