880 
tice. The prisms of the electrical organ, as 
Hunter described, are divided by very nume- 
rous horizontal diaphragms into spaces con- 
taining a thin fluid, and on these diaphragms 
the nerves and vessels of the organ are ulti- 
mately distributed in great abundance. Each 
of these superposed diaphragms consists of a 
layer, pole te double, in and not upon which 
the nerves ramify. The nerves of the electrical 
organ have never any ganglia formed upon 
them. Their tubules always have the double 
contour which marks the presence of the white 
substance of Schwann. e ramifications pe- 
netrate between the prisms, and each diaphragm 
receives tubular fibres at several points of its 
circumference, though Savi is doubtful whether 
these are derived from two or more tubules of 
the branch supplying them. In the diaphragm, 
however, they are uniformly spread out in a 
network with five or six-sided meshes, the 
sides of which are everywhere formed by a 
single tubule with double contour of the same 
diameter and structure as the tubules of the 
trunk of the nerve. If this network is supplied 
from several different tubules, these tubules 
must be described as inosculating to form it; 
if from a single tubule, this must be regarded 
as again and again branching dichotomously, 
and the branches repeatedly anastomosing. 
Whichever be correct, the existence of a true 
network of ultimate nerve-tubes with double 
contour is certainly a fact of much importance, 
and hitherto unique; and it appears to be 
satisfactorily established by the repeated accu- 
rate observations of Savi. 
The series of superposed membranes in the 
prisms of the electrical organs may have an 
analogy with the concentric capsules of the 
Pacinian bodies. Their separation by inter- 
vening fluid is another point of resemblance. 
But in their relation to the nerves they are 
quite unlike. In the one, each membrane has 
a plane network of nervous tubules in its sub- 
stance; in the other a single nerve-fibre is 
placed in the axis of a series of concentric 
membranes. The condition of the nerves is 
also different. In the one the white substance 
of Schwann everywhere invests the nerve; in 
the other it is suddenly lost on entering the 
central capsule. The branching of the nerve- 
tubes in the electrical organ has a correspon- 
dence with the frequent tendency of the pale 
fibre of the Pacinian corpuscle to divide into 
two or more parts. On the whole, perhaps, 
the comparison may suffice to raise the ques- 
tion, whether the Pacinian corpuscles may not 
be organs designed to generate some kind of 
force, which the nervous communication with 
the centres may serve to connect either with 
volition or some emotional impulse or feeling.* 
There is another set of organs, however, in 
the electric torpedo, the discovery of which we 
owe to Savi, and which bear a closer resem- 
blance to the Pacinian corpuscles than the 
electric organs themselves. These are what he 
terms the follicular nervous apparatus, and 
* Henle and Kolliker endeavoured to elicit evi- 
dence of an electric discharge from the Pacinian 
bodies of the cat’s abdomen, but without success. 
_ terior part o 
PACINIAN BODIES. 
which I shall briefly describe nearly in his own 
words.* abe »- 
“ This tus is foun ering the an- 
pe pe mouth and nostrils, and ex- 
tends over the surface of the anterior part of the 
electrical organs, and over the front half of 
their outer edge, where it rests upon the carti- 
lage and aponeurotic coverings of the fin. 
Some parts of the apparatus are found on the 
back, but the greater portion on the ventral 
surface of the animal. It consists of extensive 
linear series of follicles, or closed membranous 
cells with double walls filled with a gelatinous — 
fluid, and enclosing a small aay cae granular 
mass, which nearly resembles amorphous — 
grey matter of the cerebral hemispheres. A 
nervous branch gives some fibres to this granu- 
lar mass, while other similar fibres united into — 
bundles pass out of the follicle, the 
grey mass of the adjoining follicle, and mingle 
with its nerve. 
“ The nerves distributed to this a er 4 
come exclusively from the fifth pair, more 
particularly from the branchesspringing from the - 
anterior portion of the root. Each follicle (fig. 
486) is of aspheroidal form, slightly compressed - 
on the side which adheres to the neighbouring fol. 
licle, and its diameter is about 4th of an inch. [ 
have found these dimensions the same in ani- 
mals of very different size. These follicles a 
never free or floating in the gelatinous fluid 
abundant in these fishes ; on the contrary, they 
are always firmly fixed, as if with a special view 
to their security, for they are planted on un- 
yielding aponeurotic expansions, like that o 
the muzzle, or else on fibrous bands extendin 
along the fin, and having no other use. Wher 
the gelatinous fluid which envelopes these folli- 
cles is examined under the microscope, it is 
seen to contain numerous fibres passing in | 
rious directions, and fixed to the surface ¢ 
follicles. 
“ Each follicle is formed of two membrai 
(f and g) which adhere together on the sit 
towards the fibrous band which supports th 
organ, whilst on the opposite side they : 
separated by about a third of the  vertic 
diameter of the follicle. These organs may 
easily examined by a very slight magnify 
power, it being only necessary in the first p 
to remove the investing gelatinous substai 
and then to subject them to moderate compr 
sion for the display of their interior. Ih 
follicle thus compressed, we observe first 
cut portion of the tendinous band ce, then 
outer membrane enclosing the other, in wh 
is the rounded granular mass e already m™ 
tioned. This latter seems to rest upo 
lower wall of the internal membrane. Thi 
ternal membrane adheres by its lower bord 
the fibrous band beneath it in such a way, © 
between this external wall of the follicle 
the internal is left a space, in which the 
ramification d advances and adheres 
rounded mass of granular substance. 
“ In the follicles of the longitudinal serie 
of the fin, of which we here speak, the nervo 
a 
* Op. cit. p. 332. 
