98 
cerastes. 
he never saw so many of them as in the Cyrenai- 
cum, where the jerboa is frequent in proportion. 
They are so fond of heat, that, when our travel- 
ler and his companions made a fire at night in 
order to dress their victuals, they were generally 
visited by more than half a dozen of these vipers, 
who burnt themselves to death by approaching the 
embers. To prove the venomous nature of the 
cerastes, Mr. Bruce compelled one of them to 
scratch eighteen pigeons upon the thigh, and they 
all died nearly in the same interval of time. This 
gentleman, likewise, in some measure corroborates 
the account of Dr. Shaw respecting their absti- 
nence. He tells us that he kept two snakes of this 
species in a glass jar, such as is used for keeping 
sweetmeats in, for two years, without any food ; 
they did not sleep, that he observed, in winter, 
but cast their skins the last days of April. 
The following singular account, by Mr. Bruce, 
of the manners of the cerastes, and the different 
effect of its venom, we shall beg leave to subjoin 
in the words of the author. “ The cerastes moves 
with great rapidity, and in all directions, forward, 
backward, and sideways. When he is inclined to 
surprise any one who is too far from him, he creeps 
with his side towards the person, and his head 
averted, till, judging his distance, he turns round, 
springs upon him, and fastens upon the part next 
to him ; for it is not true what is said, that the 
cerastes does not leap or spring. I saw one of them 
