120 
EXPERIMENTS ON THE GYMNOTUS. 
it be capable of directing tbe action of its organs to an 
external object. We often tried, both insulated and other- 
wise, to touch the fish, without feeling the least shock. 
When M. Bonpland held it by the head, or by the middle of 
the body, while I held it by the tail, and, standing on the 
moist ground, did not take each other’s hand, one of us 
received shocks,, which the other did not feel. It depends 
upon the gymnotus to direct its action towards the point 
where it finds itself most strongly irritated. The discharge 
is then made at one point only, and not at the neighbouring 
points. If two persons touch the belly of the fish with their 
fingers, at an inch distance, aud press it simultaneously, 
sometimes one, sometimes the other, will receive the shock. 
In the same manner, when one insulated person holds the 
tail of a vigorous gymnotus, and another pinches the gills or 
pectoral fin, it is often the first only by whom the shock is 
received. It did not appear to us that these differences 
could be attributed to the dryness or moisture of our hands, 
or to their unequal conducting power. The gymnotus 
seemed to direct its strokes sometimes from the whole sur- 
face of its body, sometimes from one point only. This 
effect indicates less a partial discharge of the organ com- 
posed of an innumerable quantity of layers, than the faculty 
which the animal possesses, (perhaps by the instantaneous 
secretion of a fluid spread through the cellular membrane,) 
of establishing the communication between its organs and 
the skin only, in a very limited space. 
Nothing proves more strongly the faculty, which the 
gymnotus possesses, of darting and directing its stroke 
at will, than the observations made at Philadelphia and 
Stockholm,* on gymnoti rendered extremely tame. When 
* By MM. Williamson anti Fahlberg. The following account is given 
bv the latter gentleman. “ The gymnotus sent from Surinam to M. 
NSrderling, at Stockholm, lived more than four months in a state of 
perfect health. It was twenty-seven inches long; and the shocks it gave 
were so violent, especially in the open air, that 1 found scarcely any 
means of protecting myself by non-conductors, in transporting the fish 
from one place to another. Its stomach being very small, it ate little 
at a time, but fed often. It approached living fish, first sending them 
from afar a shock, the energy of which was proportionate to the size ot 
the prey. The gymnotus seldom failed in its aim ; one single stroke 
was almost always sufficient to overcome the resistance which the strat* 
