S06 PRACTICAL AND SCIENTIFIC ZOOLOGY. 



mulgated, will never compensate for the want of this 

 primary requisite. In ordinary life, we see some people 

 who have an instinctive perception of differences to a 

 much greater degree than others : as if, in short,, the 

 faculty was natural to them. Such persons will always 

 make the best naturalists. This keenness of perception 

 can, doubtless., be acquired ; and, as no science requires 

 more observation, or greater nicety of discrimination, 

 than natural history, so, upon this account only, it is 

 the very best pursuit that can engage the youthful 

 mind; since it will be thus qualified to apply that 

 acuteness and judgment upon greater things, in after- 

 life, which may call for the exercise of sound reason and 

 just discrimination. Many people, for instance, would 

 be utterly at a loss to discover the difference of structure 

 between a swift and a swallow, even if the two birds 

 were before their eyes. Their colours, it is true, are 

 not the same ; but both have little, triangular, short 

 bills, long pointed wings, and fly and feed in the same 

 manner. A glance, however, at their feet shows a ma- 

 terial difference. This difference is so great, that a 

 young naturalist would immediately be convinced they 

 could not belong to the same genus ; because these op- 

 posite structures of the feet indicated a corresponding 

 dissimilarity of manners. Again, we hear the names 

 of butterfly or moth used indiscriminately, even by well- 

 informed people ; who, were they asked why, could 

 give no satisfactory answer. A boy, who merely knew 

 the first elements of entomology, might immediately 

 answer by pointing to the antennae, or horns (as they 

 are vulgarly called), of the insect, and stating, that in a 

 butterfly these members end in a thickened knob; 

 while in the generality of moths they terminate in a fine 

 point. This tact for observation, like every other habit, 

 is to be acquired by practice ; and the more it is exer- 

 cised, the more acute it becomes. The student would 

 derive much advantage, in this respect, from placing 

 before him ten or a dozen species of insects very closely 

 resembling each other : such, for instance, as those com- 



