24' CLASS REPTILIA. 



seems rather to be attached to their spinal marrow, and to be 

 more generally disseminated throughout their body. A tor- 

 toise has been known to live for eighteen days after the brain 

 was removed, still walking about, but groping its way, for 

 its eyes were closed, and the power of vision lost in conse- 

 quence of the cutting of the optic nerves. A salamander has 

 lived several months although decapitated by means of a 

 ligature fastened tightly round the neck. The heart of a 

 viper, when plucked out, will beat and contract on being 

 pricked for the space of forty hours. From all this it 

 appears that these animals have not such a centralized life as 

 that of a quadruped or a bird, which would instantly perish 

 from similar amputations. This pertinacious irritability in 

 frogs and serpents renders them very proper subjects of gal- 

 vanic and electrical experiments. Electricity is found to 

 exercise a most powerful influence on them. Reptiles are 

 exceedingly sensible to storms, and to an electric state of the 

 atmosphere, of which they appear to forsee all the changes, 

 as appears by the croaking of frogs, &c. 



This want of concentration of vitality in the brain has, in 

 the reptiles, as its natural accompaniment, a marked dimi- 

 nution of intelligence; and though, as we hinted before, some 

 of them can be tamed, it is next to impossible to teach them 

 any thing. 



The system of respiration in reptiles is the principal cha- 

 racter which separates them from all other animals, and 

 exercises the most pov/erful influence over all the parts of 

 their organization. In organized bodies there are certain 

 general modes of conformation which necessitate a multi- 

 tude of particular conformations. Thus, for example, the 

 animal whose stomach is found to digest flesh, must be fur- 

 nished with teeth proper for tearing it, robust muscles for 

 vanquishing his prey, agile limbs for overtaking it, &c. In 

 like manner, the external organs of every being are all in 



