t)60 PHILOSOPHICAL TRANSACTIONS, [aNNO 1780. 



disorders which have begun in other parts, and those merely fluid. The illnesses 

 which arise from mental uneasiness show us the power of the nerves on living 

 bodies. But all this does not prove that all the diseases attributed to the nerves 

 are nervous ; and that the ordinary signs of this disorder are not equivocal. 

 And it is certain, that the poisons we have examined have no immediate action 

 on the nerves, as has been commonly believed hitherto. Some may object to 

 this, that the poison of the viper and the American poison may act on the ex- 

 tremities of the nerves, and that for this reason they are innocent when applied 

 to the trunk of the nerves. But this would be to object merely for the sake of 

 objection, and to fancy unnecessary difficulties. The smallest variation of cir- 

 cumstance v.'ould then be sufficient grounds for objection ; and who may not 

 find a variety in things when it is so difficult to meet with 2 things alike .-' As 

 for myself, I observe that the internal substance of the trunks of the nerves 

 does not appear different from that which forms the extremities of those nerves ; 

 that the trunk is subject to pain the same as the extremities ; and that I am no 

 inventor of hypotheses which are not confirmed by facts. 



In the universality of the consequences which I have deduced from my experi- 

 ments, I may be deceived ; and I may even be deceived in some of the experi- 

 ments themselves, notwithstanding that they have been very carefully conducted, 

 and that I have sought after truth without prejudice. I do not doubt, but tliat 

 those who may apply themselves to such researches after me, may find some 

 things to add, and perhaps some to correct also. It is sufficient for me to have 

 opened a channel to new truths, and that the principal facts which I have ad- 

 vanced are true. The greatest part of these experiments were made in the pre- 

 sence of Dr. Ingenhousz, physician to the emperor, my particular friend ; a 

 man who has manifested in several works his possessing the talents of a true ob- 

 server. Mr. Cavallo was also present at many of the more important ones. I 

 thought that the authority of 2 gentlemen, so well known to the learned, would 

 procure the more credit to my experiments. 



After having finished my experiments on the American poison, a friend in 

 London procured me a great number of East Indian arrows. I wished to make 

 some experiments on them also; but those I have made are neither many nor 

 sufficiently varied. It appears however, that this poison difi^ers not from the 

 other, except in its being less active, in killing of animals : which lesser activity 

 is probably to be attributed, either to these arrows having been less carefully 

 preserved than those from the West Indies, as really appeared to be the case, 

 or else to the poisons having been prepared many years since. I have never suc- 

 ceeded in killing any rabbit, even the smallest-sized one, with it, by applying it 

 to the skin scratched or slightly wounded, though I have used it in greater quan- 

 tities, and on more extensive parts of the skin, than the poison of Ticunas : 



