GENERAL ANALOGIES. 239 



the extremes, and in comparing them we have the 

 advantage of the greatest contrast of which the class 

 admits. There are some birds which have both habits, 

 and they are chiefly miscellaneous feeders ; and, if we 

 had only two divisions, there are very many species 

 which would belong equally to both ; to the observer 

 of the one habit they would be air birds, but they 

 would be ground birds to the observer of the other 

 habit. 



With the three divisions there would still be diffi- 

 culties on the confines, nor could we avoid similar 

 difficulties though we made three hundred divisions ; 

 for in nature there are no absolute divisions but those 

 of species, or perhaps individuals. Natural divisions 

 are, therefore, out of the question in this or in any 

 other department of natural history. But there is a 

 natural gradation, and that gradation we can approxi- 

 mate, and approximate the more nearly the better 

 that we understand the whole ; but completely to reach 

 it would require a degree of knowledge which man 

 in this world never can possess. 



The primary divisions in the arrangement which 

 has been hinted at would be as unnatural, as artificial 

 as those in any of the systems. But there would be 

 at least one great advantage, we should have the 

 whole bird presented to us in the general definition, 

 and not a mere bill, foot, or wing, as we have at 

 present. Thus we could, from a sort of general 

 enunciation, proceed equally to all the parts by 

 analysis, whereas, as matters stand at present, we 

 have to collect the knowledge of all the parts, in 

 perfect ignorance of the use which we are to make 

 of this knowledge, till we are in possession of the 

 whole. This is a very discouraging mode of going 



