OF SERPENTS. . 211 



though serpents are often seen apparently to draw in their 

 breath, yet we cannot find the smallest signs of their ever re- 

 spiring it again. Their lungs, however, are long and large, 

 and doubtless are necessary to promote their languid circula- 

 tion. The heart is formed as in the tortoise, the frog, and 

 the lizard kinds, so as to work without the assistance of the 

 lungs. It is single, the greatest part of the blood flowing 

 from the great vein to the great artery by the shortest course. 

 By this contrivance of nature we easily^gather two conse- 

 quencesthat snakes are amphibious, being equally capable 

 of living on land and in the water ; and, that also they are 

 torpid in winter, like the bat, the lizard, and other animals 

 formed in the same manner. 



As the body of this animal is long, slender, and capable of 

 bending in every direction, the number of joints in the back- 

 bone are numerous beyond what one would imagine. In the 

 generality of quadrupeds, they amount to not above thirty or 

 forty ; in the serpent kind they amount to a hundred and 

 forty-five from the head to the vent, and twenty-five more 

 from that to the tail. The number of these joints must give 

 the back-bone a surprising degree of pliancy ; but this is still 

 increased by the manner in which each of these joints are 

 locked into each other. In man and quadrupeds, the flat 

 surfaces of the bones are laid 'one against the other, and bound 

 tight by sinews ; but in serpents, the bones play one within 

 the other, like ball and socket, so that they have full motion 

 upon each other in every direction. Thus, if a man were to 

 form a machine composed of so many joints as are found in 

 the back of a serpent, he would find it no easy matter to give 

 it such strength and pliancy at the same time. The chain 

 of a watch is but a bungling piece of workmanship in com- 

 parison. Though the number of joints in the back-bone is 

 great, yet that of the ribs is still greater ; for, from the head 

 to the vent, there are two ribs to every joint, which makes 

 their number two hundred and ninety in all. These ribs are 

 furnished with i muscles, four in number ; which being in- 

 serted into the head, run along to the end of the tail, and 



