356 ' CLASS REPTILIA. 



as large as those of wrens or titmice. These exclude the 

 young, in the womb of the mother, and there they remain 

 coiled up, and come to the length of three or four inches, 

 before they issue forth, which they generally do in the course 

 of the fourth month after fecundation. 



Having thus, by a sort of parturition, quitted their mo- 

 ther, the young vipers, for some time after, carry with them 

 the remains of the egg which enclosed them, and which then 

 have the appearance of irregularly torn membranes. But 

 from that time, they are entirely strangers to the being which 

 gave them birth, and do not seek refuge in her mouth, on the 

 approach of danger, as the ancients erroneously imagined. 



After the season of love, the vipers appear less frequently, 

 and even during midsummer they are not very often to be 

 met with. They disappear altogether when the first symp- 

 toms of cold begin. 



The duration of life in these reptiles, is nearly unknown, 

 but it may be presumed that they can live a considerable 

 number of years ; for, though they are reproductive from 

 their third spring, they do not acquire their entire develop- 

 ment, in less than six or seven years. 



It is with considerable difficulty that the vipers are de- 

 stroyed ; they will resist very severe wounds, and are not 

 even easily to be strangled. They can remain many hours 

 in the water without perishing, and for some minutes even in 

 brandy. 



It may also be observed that the number of their enemies 

 is but small. Excepting man, who wages continual war 

 against them, the wild boar, whose lard secures him from 

 their bite, and the falcons and herons which feed upon them, 

 all other animals, wild and domestic, fear and fly them. 



In certain countries of Russia and Siberia, vipers are said 

 to be held in singular respect, in consequence of a belief 

 among the people that if they were to kill one of these rep- 



