62 



CLASS REPTILIA. 



inclines his shell, by setting it against the wall, to collect and 

 admit every feeble ray," 



On the observation of this amiable and agreeable writer 

 relative to the longevity of the tortoise, we may remark, that 

 it is more philosophical to consider the necessary conditions 

 of life in any being, than to puzzle ourselves about the final 

 causes of its duration. Without reference to peculiarity of 

 constitution, we might pronounce, in a general way, that the 

 life of any animal passed in great activity and intense enjoyment, 

 will, of necessity, be comparatively short. The capital of life, 

 if we may be permitted to use such a phrase, is sooner spent. 

 When the functions of an animal are numerous and energetic 

 in their action, when its sensations are lively and varied, its 

 constitutional vivacity great, and it appears, as it were, to 

 be perpetually under the influence of a powerful stimulus, 

 we may naturally expect that the vital principle will be soon 

 exhausted, unless, as is the case in some few instances, a 

 strong counteracting principle is found in the strength, soli- 

 dity, and compactness of the different systems of which its 

 structure is composed. This principle does exist in some 

 mammalia and birds, which are, therefore, longer lived than 

 others; but, in general, we find that the species endowed 

 with most activity and evident sense of enjoyment, are not 

 at all distinguished for longevity. The result of the most 

 extended and accurate observations on nature confirms one 

 great truth, which may be laid down as an axiom ; namely, 

 that to procure certain advantages, a certain arrangement is 

 necessary, and that this arrangement is quite incompatible 

 with other and opposite advantages. Any arrangement cal- 

 culated to secure the latter must exclude the former. The 

 activity of the lively bird, incessantly on the wing ; the 

 longevity and tenacity of life in the cold-blooded reptile ; and 

 the intelligence of man, cannot co-exist in any material being, 



