242 STUDY OF NATURAL HISTORY. 



every natural group. Now, as there must, in the 

 natural system, be a harmony of design, that har- 

 mony, if it is not universal, and extending to the 

 most minute particulars, cannot be worthy of those 

 attributes belonging to the God of Nature. We 

 must not, therefore, content ourselves with noting 

 the variations we are speaking of, and viewing them 

 as simply confined to the group in which they occur; 

 for this would be taking a narrow and confined view 

 of things. Our business is to trace them in all 

 other groups — not only such as are adjoining, but in 

 those belonging to the same great division of animals : 

 we must, as it were, ascertain how far they are ampli- 

 fied and expanded ; and trace their prevalence in as 

 wide a circle, and through as great a number of other 

 assemblages, as possible. We should ever bear in 

 mind, that nature every where presents those two 

 kinds of relations already explained, namely, affinity 

 and analogy; and that both these universally be- 

 long to all groups. Hence we may conclude that 

 there must be a certain order in which analogies 

 occur, and that the series in one group will occur 

 in precisely the same order in another. Were it 

 otherwise, there would be a want of harmony, utterly 

 inconsistent with that ideal perfection which we 

 attach to the system of nature. Accordingly it 

 has been found, that in a number of ornithological 

 groups, these analogies do actually occur in precisely 

 the same order, and with the same regularity, as the 

 seasons of one year follow and correspond to the 

 seasons of another. It is, then, to these modifi- 

 cations of form which every circular genus presents, 

 that we give the name of sub-genera (144.). Now, 



