AND OBSERVATIONS ON THE TORPEDO. 
277 
Without reverting to the conjectures which, in passing, I have offered on 
the subserviency of the electricity of the torpedo in an auxiliary manner to 
digestion, respiration and the secretion of mucus, I may remark that its chief 
use appears to be for purposes of defence, to guard it from its enemies, rather 
than to enable it, according to vulgar opinion, to destroy its prey and provide 
itself with. food. Small smelts, which I kept in the same vessel with torpedos, 
appeared to have no dread of them, and I believe they fed on their mucus; 
and, in an experiment in which, in a confined space, I excited an active tor¬ 
pedo to give shocks, a smelt which was with it was evidently alarmed, and 
once or twice, when exposed to the shock, leapt nearly out of the vessel; but 
was not injured by the electricity. In confirmation I may add, that the elec¬ 
tric power of the young fish, which most requires it for its protection, is pro¬ 
portionally very much greater than that of the old, and can be exerted without 
exhaustion and loss of life much more frequently. After a very few shocks 
most of the old fish which I have had, have become languid, and have died in 
a few hours, whilst young ones from three to six inches long have remained 
active during ten or fifteen days, and have never failed to show the effects I 
have described. 
Before concluding, I could wish to explain the difference of the results of 
the experiments made by my brother, and of those I have detailed ; but I must 
confess my inability to do it in a satisfactory manner. Knowing his great 
accuracy in experimenting, I am confident that their failure, or negative results 
must have depended on some circumstance deserving of investigation, and 
which I hoped by inquiry to discover. 
I once imagined that they might have depended on the kind, or variety of fish 
employed. But the experiments I have made with a view to this have not 
borne me out in the conjecture. I have tried very many different specimens 
of the two varieties of the torpedo most common in the Mediterranean, the 
mottled and the spotted, called at RomeTremola and Occliiatella, without per¬ 
ceiving any distinguishable difference of electrical effect. 
It appeared possible that the sex of the fish might have some influence on its 
electricity, or that in the instance of the female fish, the state of the ovaries 
whether pregnant or not, might have an influence. But observation does not 
confirm the probability of either opinion. I have used, I believe, as many males 
2 o 
MDCCCXXXII. 
