AND OBSERVATIONS ON THE TORPEDO. 
273 
way, seems to be indicated, not only by the situation of these glands, between 
and surrounding the electrical organs, but still more so by the manner in which 
they are supplied with nerves, either from the first electrical, or from the fourth 
pair, which is connected with that nerve. As the thick semitransparent mucus 
which these glands secrete, is probably a better conductor of electricity than 
the skin alone, or than salt water, this mucous system may serve as a medium 
of communication between the electrical organs *. I shall mention some re- 
sults which are favourable to this idea. When one contact-wire was placed 
underneath an active torpedo, just anterior to the mouth, and the other at the 
extremity of the back, out of the circle of the mucous apparatus, the shock of 
the fish had no effect either on the multiplier, or on needles in the spiral. But 
when the upper contact-wire was made to touch the back of one electrical 
organ, the under wire being placed as in the preceding experiment, then both 
effects were simultaneously produced ; and they were also produced when the 
two wires were brought very close to each other, one being kept as before, and 
the other moved immediately over it, in front, each about a quarter of an inch 
from the margin, and not connected with the electrical organs, except by the 
common integuments and this mucous apparatus. It is worthy of remark, 
that this little space in front, intermediate between the two electrical organs, 
so abounding in glandular structure, and so amply provided with nerves, 
appears from experiment to possess very little sensibility ; this was denoted in 
these trials, in which the fish, though exquisitely sensible of pressure on the 
margin of the pectoral fins, seemed indifferent to it when applied in front, — 
as if the fourth pair, which supplies this part, were destined rather for secretion 
than for the purpose of sensation. 
The connexion between the electrical nerves and the mucous system, even 
more remarkable than between the former and the stomach, may perhaps war- 
rant the conjecture, that the electrical function may not only be aided by, but 
also aid the secretion of mucus ; and that, as was supposed in regard to the 
stomach, when the electricity is not employed in repelling an enemy in violent 
efforts, it may be exercised gently in increasing the activity of these glands. 
* Some comparative experiments which I have made seem to indicate that the mucus of the torpedo 
is a better conductor than sea water ; when the hands were smeared with this mucus, or when a portion 
of the fresh skin of a torpedo, with its natural mucus adhering to it, was wrapped round the ends of the 
contact- wires by which they were held, the shock received appeared to be stronger than usual. 
