VOL. XXXII. PHILOSOPHICAL TRANSACTIONS. ()43 



belly, and both of them head foremost. When they charm, they make a hoarse 

 noise with their mouths, and a soft rattle with their tails, the eye at the same 

 time fixed on the prey. 



Their general food consists of toads, frogs, crickets, grashoppers, and other 

 insects, but principally of ground mice ; and the rattlesnake again serves for 

 food to bears, and even our hogs will eat them without harm. 



They are viviparous, and bring forth generally about 1 2, and in the month 

 of June. A friend of mine in the country, being desirous to discover the na- 

 ture and manner of the generation of the rattlesnake, gave me the following 

 account, viz. About the middle of May, the time when the rattlesnakes first 

 come abroad, he took and opened one of them, and in the matrix found 12 

 small globes, as large as a common marble, in colour like the yolk of an egg ; 

 in 3 or 4 days more, he took and opened another, and then plainly perceived a 

 white speck in the centre of the yellow globe ; in 3 or 4 days more, he dis- 

 sected a 3d, and discovered the head of a snake; and in a few days after that, 3 

 quarters of a snake were formed, lying round in a coil. In the latter end of 

 June, he killed an old one, and took out perfect live snakes of 6 inches long. 

 In September, when the old ones take their young in, and carry them to their 

 dens, they are not quite a foot long. They couple in August, and are then 

 most dangerous. 



They are generally from 3 to 5 feet long, and do not commonly exceed 20 

 rattles. They shed, or throw off their skins every year, sometime in the month 

 of June, and turn it inside out when they throw it off. It has also been ob 

 served, that the skin covers not only the body, but the head and eyes. 



They generally den among the rocks in great numbers together; the time ot 

 their retiring is about the middle of September, and they do not come abroad 

 till the middle of May, when the hunters watch them, as they come out a 

 sunning, and kill them by hundreds, 



Roxhury, NeW'England, Oct. 25, 1722. 



Some Observations upon Vipers ; on occasion of the foregoing Relation. By 

 C. J. Sprengell, M. /)., F. R. S. N'^ 376, p. 296. 



At Milan I found a viper-catcher, who seldom was without 60 or more living 

 vipers, kept together in a back room open at the top ; he had them from all 

 parts of Italy, and sold them dead or alive, according to the uses they were 

 designed for. He having got one day a female viper big with young, gave me 

 notice to see her manage her prey. We catched some mice, and throwing 

 them in one at a time, among all that number of vipers, which were rather 

 above 60, none of them in the least concerned himself about the mouse 



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