ORDER SAURIA. 173 



may easily conceive how, every year during a determined 

 term, these animals fall into a state of torpor rendered in- 

 evitable by circumstances of temperature to which birds and 

 mammalia seem insensible. 



Internal and external causes, therefore, unite to diminish 

 the interior activity of the saurians, and to deprive them, at 

 certain seasons, of the brutal instinct, the physical propen- 

 sions, by which they are habitually influenced, to remove all 

 sexual desire, to silence the calls of appetite, and, in a 

 word, to place them in that lethargic kind of sleep which is 

 the most prolonged and perfect image of death, which beings 

 in which the vital spark is not extinct, can exhibit. 



Being less sensible at all times, less animated by lively 

 passions, less agitated within, and consequently less active 

 without, pretty well sheltered against violent dangers, and 

 having few accidents, comparatively, to dread, the saurians 

 without loss of life, may be deprived of feet, tail, and other 

 important parts, and even, after a time, reproduce them. So 

 extraordinary a phenomenon suffices to prove how little the 

 different parts of these beings are dependant on each other. 

 Their nervous system constitutes a whole, the various pieces 

 of which are far from being so closely connected as in birds 

 and mammalia. We may also observe that, notwithstanding 

 the burning climates which they usually inhabit, the saurians, 

 ■^ being less influenced by internal heat, have much less occa- 

 sion to drink than the animals of the two classes above 

 them. 



The slowness of the circulation and low temperature of 

 blood in these reptiles, while it explains the fact of their not 

 dying immediately wlien deprived of their head, also agrees 

 with their astonishing facility of supporting want of food. 

 This is so great that crocodiles have been known to pass a 

 whole year without taking any kind of nourishment. 



But though they have the power of resisting blows and 



