APPENDIX. 207 



By this flat pofition of the tooth along the jaw, and its 

 being defended by the membrane, it eats in perfect fafety ; 

 for the tooth cannot prefs the bag of poifon at the root 

 while it lies in this pofition, nor can it rife in the tube to 

 fpill itfelf, nor can the tooth make any wound fo as to re- 

 ceive it, but the animal is fuppofed to eat but feldom, or 

 only when it is with young. 



The viper has but one row of teeth, none but the ca- 

 nine are noxious. The poifon is very copious for fo 

 fmall a creature, it is fully as large as a drop of laudanum 

 dropt from a vial by a careful hand. Viewed through a 

 glafs, it appears not perfectly tranfparent or pellucid I 

 mould imagine it hath other refervoirs than the bag under 

 the tooth, for I compelled it to fcratch eighteen pigeons 

 upon the thigh as quick as poflible, and they all died near- 

 ly in the fame interval of time ; but I confefs the danger at- 

 tending the difTection of the head of this creature made 

 me fo cautious, that any obfervation I fhould make upon 

 thefe parts would be lets to be depended upon. 



People have doubted whether or not this yellow liquor 

 is the poifon, and the reafon has been, that animals who 

 had tafted it did not die as when bitten, but this realon 

 does not hold in modern phyfics. We know why the fa- 

 liva of a mad dog has been given to animals and has not 

 affected rhem ; and a German phylician was bold enough 

 to diilil the pus, or putrid matter, flowing from the ulcer 

 of a perfon infected by the plague, and tafle it afterwards 

 without bad confequences ; fo that it is clear the poifon 

 has no activity, till through foirie fore or wound it is ad- 

 mitted into circulation. Again, the tooth itfelf, diveilcd of 



a thai 



