210 OF SERPENTS. 



rest remains in the gullet, till putrefaction and the juices of 

 the serpent's body unite to dissolve it. The teeth in all are 

 crooked and hollow ; and, by a peculiar contrivance, are 

 capable of being erected or depressed at pleasure. 



The eyes of all serpents are small, if compared to the length 

 of the body ; and though differently colored in different kinds, 

 yet the appearance of all is malign and heavy ; and from 

 their known qualities, they strike the imagination with the 

 idea of a creature meditating mischief. In some, the upper 

 eye-lid is wanting, and the serpent winks only with that be- 

 low ; in others, the animal has a nictitating membrane or 

 skin, resembling that which is found in birds, which keeps the 

 eye clean, and preserves the sight. The substance of the eye 

 in all is hard and horny j the crystalline humor occupying a 

 great part of the globe. 



The holes for hearing are very visible in all ; but there are 

 no conduits for smelling, though it is probable that some of 

 them enjoy that sense in tolerable perfection. 



The tongue in all these animals is long and forky. It is 

 composed of two long fleshy substances, which terminate in 

 sharp points, and are very pliable. At the root it is connected 

 very strongly to the neck by two tendons, that give it a 

 variety of play. Some of the viper kind have tongues a fifth 

 part of the length of their bodies ; they are continually dart- 

 ing them out, but they are entirely harmless, and only terrify 

 those who are ignorant of the real situation of their poison. 



If from the jaws we go on to the gullet, we shall find it 

 very wide for the animal's size, and capable of being distend- 

 ed to a great degree ; at the bottom of this lies the stomach, 

 which is not so capacious, and receives only a part of the 

 prey, while the rest continues in the gullet for digestion. 

 When the substance in the stomach is dissolved into chyle, 

 it passes into the intestines, and from thence goes to nourish- 

 ment, or to be excluded by the vent. 



Like most other animals, serpents are furnished with lungs, 

 which are serviceable in breathing, though- we cannot per- 

 ceive the manner in which this operation is performed : for 



