XXXIV 
Abbe fontana on the 
For a comparative experiment I prepared, as above, the nerves, 
of two other rabbits, which I cut, but did not apply the poifon 
to : one of them died in thirty-fix hours, but the other was 
living the third day after. 
The uniformity of the refults of thefe experiments upon the 
nerves induced me to think it quite fuperfluous to repeat them ; 
and, I am perfuaded, they will leave no doubt with any one who 
is accuftomed to experiments, and not prejudiced in favour of 
ill grounded hypothefes. Hence it follows, that the American 
poifon is not poifonous when applied to the nerves ; and that in 
fuch cafes it produces no fenfible diforder in the oeconomy of 
living animals : this is what the experiment direftly eftablifhes. 
But to fuppofe what has not been obferved ; to believe what is 
contradifled by experiments is dreaming in philofophy, running 
after error inftead of truth, and adopting mere fancies for fadts. 
The American poifon (fimilar in this refpedt to the poifon of the 
viper) is not poifonous, but quite innoxious, applied in any man- 
ner whatfoever, to the nerves. But it kills in a moment, and 
with the fmalieft quantity, when introduced immediately into 
the blood by the jugular, as does likewife the poifon of the viper. 
Its adtion is therefore all upon the blood, and not in the leaf!: 
upon the nerves, whatever may be the principle or the mecha- 
nifm by which death is produced. 
The effedts and alterations caufed in the blood by the poifon 
of the viper are more determinate and more evident. Here a 
coagulation undeniably happens, which is not obfervable in the 
blood of animals killed by the American poifon ; but the latter 
^produces a great change in the lungs, which are greatly difordered 
by it. 
It is true, that death happens fo fuddenly after introducing 
the American poifon into the veffels, that one cannot well com- 
prehend how it can take place in fo fhort a time ; for it may be 
faid, that the poifon is hardly arrived at the heart before the 
animal is dead : nor is it well underftood, how cold-blooded 
animals can be killed by it (frogs, for inftance, which live fo 
long with the circulation flopped) although it be true that they 
die much flower by thefe poifon s than other animals whofe blood 
