/ 
of catching them hy means of Wild Morses. 247 
tus, recently taken, was not yet sufficiently tamed to attack and 
devour frogs. On approaching the finger, or metallic points, 
within the distance of half a line from the electric organs, no 
shock was felt. Perhaps the animal did not perceive the neigh- 
bourhood of this foreign body ; or, if it did, we must suppose 
that the timidity it felt in the commencement of its captivity, 
prevented it from darting forth its energetic strokes, except 
when strongly irritated by an immediate contact. The gymno-- 
tus being immersed in water, I approached my hand, both 
armed and unarmed with a metal, within the distance of a few 
lines from the electric organs ; yet the strata of water transmit- 
ted no shock, while Mr Bonpland irritated the animal strongly 
by an immediate contact, and received some very violent shocks. 
If I had plunged the most delicate electroscopes we know, pre- 
pared frogs, into contiguous strata of water, they would no 
doubt have felt contractions at the moment when the gymnotus 
seemed to direct its stroke elsewhere. 
The electrical organ of the gymnOti acts only under the im- 
mediate influence of the brain and the heart. On cutting a very 
vigorous fish through the middle of the body, the fore part a- 
lone gave me shocks. The shocks are equally strong, in what- 
ever part of the body the fish is touched ; it is most disposed^ 
however, to dart them forth when the pectoral fin, the electri- 
cal organ, the lips, the eyes, or the gills are pinched. Some- 
times the animal struggles violently with a person holding it by 
the tail, without communicating the least shock. Nor did I feel 
any when I made a slight incision near the pectoral fin of the 
fish, and galvanized the wound by the simple contact of two 
pieces of zinc and silver. The gymnotus bent itself convulsive- 
ly, and raised its head out of the water, as if terrified by a 
sensation altogether new ; but I felt no vibration in the hands 
which held the two metals. The most violent muscular move- 
ments are not always accompanied by electric discharges. 
The action of the ^fish on the organs q£ man is transmitted 
and intercepted by the same bodies that transmit and intercept 
the electrical current of a conductor charged by a Leyden vial,, 
or Volta’s pile. 
In wounded gymnoti, which give feeble but very equal 
shocks, these shocks appeared to us constantly stronger on 
