1 66 SNAKES. 



and awake In an enfeebled condition, only gradually recover- 

 ing their normal strength after some days. 



The power of endurance in serpents, and their independ- 

 ence of a large supply of oxygen, render them important 

 agents in the economy of nature. In the swamps and 

 morasses where malaria abounds, reptiles are most numerous. 

 Many such places under canopies of pestilential vapours, 

 swarm with insects, molluscs, worms, caterpillars, and 

 the smaller reptiles on which snakes mostly feed. They 

 are, therefore, the scavengers of such localities ; they fulfil a 

 great law by keeping up the balance of nature even to the 

 extent of rendering certain countries habitable. 



Those ophidian families which prefer higher lands, sandy 

 or rocky districts, select the sunny hill-sides when the frost 

 sets in, and hide themselves under stones or in caves where, 

 as described in the chapter on rattlesnakes, they congregate 

 in vast numbers. Piles and convolutions of serpents in this 

 condition have often been discovered, and as often described. 

 It is as if the small degree of animal warmth each one pos- 

 sessed were harvested for their mutual good, and to the 

 benefit of the whole community. Nor are these assemblages 

 at all exclusive as to kind, but are dens of discordant 

 materials, where, as an American wrote, 'the liberal terms of 

 admission seemed only to require the evidence of snakeship.' 

 Lizards, too, though of widely - branching kinship, are 

 guided by the same instinct, and sometimes share the 

 retreat. 



A few years ago, near Hayward's Heath in Sussex, some 

 men who were levelling the ground for building, dug out of 

 a bank at a depth of from four to five feet, upwards of one 



