726 



A HISTORY OF 



assistance of the lungs. It is single, the great- 

 est part oi' the blood flowing from the great 

 rein to the great artery by the shortest course. 

 By this contrivance ot" nature we easily ga- 

 ther two consequences that snakes are am- 

 phibious, 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 man- 

 ner. 



The vent in these animals serves for the 

 emission of the urine and the fasces, and for 

 the purposes of generation. The instrument 

 of generation in the male is double, being 

 forked like the tongue; the ovaries in the 

 female are double also ; arid the aperture is 

 very large, in order to receive the double in- 

 strument of the male. They copulate in their 

 retreats; and it is said by the ancients, that 

 in this situation they appear like one serpent 

 with two heads : but how far this remark is 

 founded in truth, I do not find any of the mo- 

 derns that can resolve me. 



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 nu- 

 merous 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 the other. In man and quad- 

 rupeds, the flat surfaces of the bones arc 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. 1 " 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 comparison. 



Though the numbnr of joints in the back- 

 bone is great, yet that of the ribs is still great- 



Charat. Anatona, b Derham, p. 39fc>. 



er; 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 muscles, four in num- 

 ber; which being inserted into the head, run 

 along to the end of the tail, and give the ani- 

 mal great strength and agility in all its motions. 



The skin also contributes to its motions, 

 being composed of a number of scales, united 

 to each other by a transparent membrane, 

 which grows harder as it grows older, until 

 the animal changes, which is generally done 

 twice a year. This cover then bursts near 

 the head, and the serpent creeps from it, by 

 an undulatory motion, in a new skin, much 

 more vivid than the former. If the old slough 

 be then viewed, every scale will be distinctly 

 seen, like a piece of net-work, and will be 

 found greatest where the part of the body 

 they covered was largest. 



There is much geometrical neatness in the 

 disposal of the serpent's scales, for assisting 

 the animal's sinuous motion. As the edges 

 of the foremost scales lie over the ends of their 

 following scales, so those edges, when the 

 scales are erected, which the animal has a 

 power of doing in a small degree, catch in 

 the ground, like the nails in the wheel of a 

 chariot, and 1 so promote and facilitate the ani- 

 mal's progressive motion. The erecting these 

 scales is by means of a multitude of distinct 

 muscles, with which each ia supplied, and 

 one end of which is tacked each to the mid- 

 dle of the foregoing. 



In some of the serpent kind there is the ex- 

 actest symmetry in these scales; in others 

 they are disposed more irregularly. In some 

 there are larger scales on the belly, and of- 

 ten answering to the number of ribs; in others, 

 however, the animal is without them. Upon 

 this slight difference, Linnreus has founded 

 his distinctions of the various classes of the 

 serpent tribe. Human curiosity, however, 

 and even human interest, seem to plead for 

 a very different method of distribution. Il is 

 not the number of scales on a formidable ani- 

 mal's belly, nor their magnitude or variety, 

 that any way excite our concern. The first 

 question that every man will naturally ask, 

 when he hears of a snake, is, whether it be 

 large? the second, whether it be venomous? 

 In other words, the strongest lines in the ani- 



