CAKTILAGLNOUS FISHES. 
f>07 
The organ which produces this curious result is formed like a half 
moon ; it is double, and placed on each side of the mouth of the 
respiratory organs. It consists of a multitude of small prisms arranged 
parallel the one to the other and perpendicularly to the surface ; 
twelve hundred and sixty-two of these prisms have been counted in 
one of the two organs of a torpedo, three feet in length. Without 
entering into the anatomical descriptions which have been given by 
btannius, Max fechultze, Breschet, and others, we may mention here 
that all the small parallelopipedes, which enter into their structure, are 
separated one from the other by walls of cellular tissue, in which are 
distributed the vessels and nerves. The nervous threads which each 
apparatus receives are divided into four principal trunks. According 
to modern authors, the electricity is elaborated in the brain under the 
influence ol the will. It is alterwards transferred by means of the 
uervous threads into the principal organ, where it serves the purpose 
of charging the numerous little voltaic piles which constitute the organ 
of commotion. 
It is, nevertheless, necessary to receive our comparisons of the 
apparatus of the torpedo with the voltaic pile of our laboratories with 
caution. The apparatus resembles a good conducting body, which 
is capable of being strongly electrified ; it is sufficient to touch one 
of the surfaces in order to receive the shock. But if the little prisms 
composing it were charged like our voltaic piles, it would he necessary 
to touch both their surfaces iu order to receive the shock. No real 
analogy can therefore exist between this natural apparatus and the 
scientific instrument named after Yolta. 
It is possible by the aid ol heat to restore the extinct or suspended 
electrical functions of the torpedo. Betained in a tank of sea-water, 
a yard in height by a third of that in diameter, and at 22° Centi- 
grade in temperature, a torpedo preserved its faculties during five 
or six hours ; another, which remained during ten hours in a very 
small quantity of sea-water at a temperature of 10° to, 11° Cent., 
and which seemed dead, revived a little when placed in water 
at 20° Cent., and gave shocks during an hour. If held firmly 
V the tail and pressed both above and below' by a platinum rod 
to gather the true electricity, the animal contracts itself violently ; 
,J ut its movements are not always accompanied by electrical dis- 
charges, which demonstrate that the jets of electrical matter are not 
