56 SNAKES. 



Some other general characteristics of the Ophidia are that 

 all are carnivorous, catching their prey alive; all are ovipar- 

 ous ; and in organization and intelligence they rank between 

 birds and fishes, — higher than fishes in having lungs, and 

 lower than birds, which are warm-blooded animals. Theirheart 

 is so formed as to send only a portion of blood to the lungs 

 on each contraction of it ; their temperature, therefore, is that 

 of the surrounding atmosphere (see p. 142). Their normal 

 condition, particularly that of the venomous species, is one 

 of lethargic repose and indolence, with a disposition to 

 retreat and hide, rather than to obtrude themselves. On 

 this account, and also because so many of them are nocturnal 

 in their habits, less has been truly known of serpents than 

 of most other creatures, prejudice having added to a pre- 

 vailing indifference regarding them. The duration of their 

 lives is uncertain, or whether they have a stated period of 

 growth. Some naturalists think they grow all their lives ; 

 but this must not be taken literally, or that if a small snake 

 happened to escape dangers, and live a very long while, 

 it would acquire the dimensions of a python. Some think 

 that formerly the constrictors did attain more formidable 

 proportions than those of the present day. 



Snakes have small brains, slight intelligence, and slow 

 sensations, amounting almost to insensibility to pain. They 

 can live a long while without their brains and without their 

 heart ; while the latter, if taken from the body, will con- 

 tinue its pulsations for a considerable time. Also if the 

 head be severed, the body will for a certain time continue 

 to move, coil, and even spring, and the head will try to 

 bite, and the tongue dart out as in life. 



