EXTERNAL CHARACTERS PREFERABLE. 247 
well distinguished from each other by external 
characters, which require no dissection of their 
mouths; such a mode of discriminating them is to 
be preferred before all others, for the best of 
reasons—as being the most simple and obvious. 
Nor should we be tempted to employ anatomical 
characters, or such as are taken from the different 
modifications in the masticating organs, until we 
are absolutely compelled to do so by the failure of 
other resources. This, indeed, is in direct contra- 
diction to the usual mode of proceeding pursued 
by modern naturalists; but, in the present state 
of natural history, and, indeed, of all science, it 
appears to us that one of the chief objects of its 
professors should be as much as possible to simplify. 
The science they would teach, and which they of 
course desire that others should learn, can only be 
rendered inviting to mankind in general, by being 
divested of all verbose technicality and minute 
investigation, not absolutely essential. If the same 
object can be arrived at by two roads— one smooth 
and comparatively easy, the other intricate, winding, 
and difficult — no one, in his rational senses, would 
choose the last in preference to the first. The same 
analogy should be pursued in science. Simplicity, 
perspicuity, and brevity should be the characteristics 
of all systematic distinctions, whether of groups or 
of species ; and the more we study nature, the more 
shall we find that in this, as in all other branches 
of physical science, the laws which are most simple 
are at the same time the most universal. 
(171.) Essential characters, or such as pre-emi- 
nently distinguish a group from all others, are 
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