544 PHILOSOPHICAL TRANSACTIONS. [anNO 1 67O. 



with a discourse on their vegetability, and the discussion of many difficult 

 questions belonging to chemistry. Collected out of the most approved authors, 

 that have written in Greek, Latin, High Dutch and English : with some ob- 

 servations and discoveries of his own. 



III. Lettera di Francesco Redi sopra alcune Oppositioni alle sue Observationi 

 intorno alle Vipere. In Firenze, 1670, in 4to. 



Mons. Charas having endeavoured in his book, entitled, Nouvelles Expe- 

 riences sur la Vipere, not long since translated into English (of which an ac- 

 count was given in Number 54 ;) first, by experiments to confute the opinion, 

 that the venom of vipers resides in the yellow liquor contained in the bag about 

 the vipers' teeth, and then to maintain on the contrary that it consists in their 

 vexed and enraged spirits ; this author being concerned in this controversy, 

 and having made out the former of these opinions, as he thinks, by numerous 

 experiments, affirms now in this letter, that he repeated his former trials again 

 and again, and is thereby altogether confirmed in what he then delivered about 

 the seat of the vipers' poison ; concluding with more assurance than ever, that 

 the venom of the Italian vipers does not consist in an imaginary idea of re- 

 vengeful choler, but in that yellow liquor above-mentioned ; which, he says, 

 if it chance to shed or spread itself over the mouth and palate of the viper, 

 may make that saliva poisonous which moistens the throat of that animal. 

 On which account he proposes that the authors of the French experiments 

 should make new observations ; which might prove, if conformable to the 

 opinion already published, that the venom of French vipers consists in a 

 choleric and vindicative idea of the fancy ; but that of the Italian has its seat 

 in that yellow juice so often spoken of: and that, if this latter prove true, it 

 will be no untruth to affirm, that, if a viper by biting should have consumed 

 both all the provision, which is lodged in the bags of her teeth, 'and that also, 

 which from the neighbouring parts may be furnished, that then her bitings 

 would not be mortal : which he says he has heretofore affirmed, and doth so 

 still ; although M. Charas deny ft, declaring that one only viper being en- 

 raged is able to kill as many animals as she shall bite. 



In this vindication our author alleges many new experiments to maintain 

 his opinion ; and also some very remarkable observations, to show that vipers 

 kill some animals more easily than others ; that their biting in some places is 

 more dangerous than in others ; and that a plentiful effiasion of blood after the 

 biting is capable of saving the bitten animal, &c. 



Among the many new experiments, he relates one which is not to be passed 

 by ; viz. That he had put up in a glass vessel the poisonous liquor taken out of 

 two hundred and fifty vipers, with a design to make various trials as often as he 



