^§ PHILOSOPHICAL TRANSACTIONS. [aNNO 1666. 



Some Ohservations on Vipers. By Sig. Redi. N° 9, p- 160. 



These observations are taken from the account given in the Journal des 

 Sqavans for January 1665-6, of Francis Redi's treatise, v^herein it is stated — 



1. That the poison of vipers is neither in their teeth, nor in their tail, nor 

 in their gall ; but in two vesicles or bladders which cover their teeth, and which 

 being compressed; when the vipers bite, emit a certain yellowish liquor, that 

 runs along the teeth and poisons the wound.* Whereof he gives this proof, 

 that he hath rubbed the wounds of many animals with the gall of vipers, and 

 pricked them with their teeth,-|- and yet no considerable ill accident followed 

 upon it ; but that as often as he rubbed the wounds with the said yellow liquor 

 not one of them escaped. 



2. Whereas commonly it hath hitherto been believed that the poison of 

 vipers being swallowed, was present death : this author after many reiterated 

 experiments is said to have observed, that in vipers there is neither humour nor 

 excrement, nor any part that being taken into the body kills : And he asserts 

 that he hath seen men eat, and has often made brute animals swallow, all that is 

 esteemed most poisonous in a viper, yet without the least mischief to them ; 

 agreeably to the doctrine of the ancients. Venenum serpentis, ut qucedam etiam 

 venatoria venena, non giLstu, sed in vulnere nocent. Celsus. ;|: 



* We owe to Redi the discovery of the fluid which constitutes the viper s poison , tut he mistook 

 its exact situation when he placed it in the membrane which covers the upper fangs (tlie canine 

 teeth) J whereas it is lodged (as our countryman Mead has shown) in a peculiar bag or secretory- 

 vesicle seated at the basis of those teeth. Moreover, it escaped Redi that the venomous fangs were 

 perforated, 'and that when the animal bites, the poison is squeezed into the wound, not along the out- 

 side of the teeth, but through tlieir interior^ along the conduits or perforations which terminate near 

 their apices or points. Mead has described only a single perforation in each of tlie venomous fangs j 

 but Fontana asserts there are two in each. See the last mentioned author's Traite sur le Venin de la 

 Vipere, torn. i. p. 6 — 8. 



f This assertion of Redi's is not accurate. It is evident that, in the before-mentioned perforations or 

 canals of the canine teeth, there will always remain some of the venomous fluid, and therefore there '■ 

 will always be a greater or less risk of being poisoned when pricked by tliem. In two experiments 

 Fontana killed animals by wounding them with a viper's tooth, several hours after it had been drawn 

 out of the head. 



+ This assertion is contradicted by the later experiments of Fontana, who having forced into the 

 oesophagus of a pigeon a tea spoonfol of the poison, it was quickly seized with strong convulsions and 

 died in less than six minutes. He doubts not it would produce the same fatal effects, when taken 

 into the stomach, upon man and other larger animals, provided it were swallowed in sufficient quanti- 

 ties. Traite sur le Venin, &c. tom. ii. pp. 308, 309. It would appear, however, to be trae, as Redi 

 has stated, that the flesh of animals killed by vipers may be safely eaten, and the wound inflicted by 

 their bite sucked with impunity ; because, in either of these ways, the dose of the poison swallowed 

 will be too inconsiderable to produce, in so large an animal as man, any powerful effect. 



