PACINIAN BODIES. 
Fig. 485. 
Portion of a Pacinian corpuscle, from the mesentery 
of a cat. 
aa, the internal capsules; 6 6, capsules of the 
external system, with intervening fluid. Corpuscles, 
as atc, are seen in all ‘the capsules. The outer 
‘capsules show a double layer, d; e, occasional form 
of corpuscle in the intercapsular spaces; nm, con- 
necting membrane between two capsules; 0, capil- 
vessel containing corpuscles or nuclei in its 
wall, and lying with p, a tubular nerve-fibre in g, 
the ape of the stalk, the fibrous tissue sur- 
rounding them not being represented. The vessel 
divides into two branches, one of which perforates 
the wall of the channel of the stalk and enters an 
intercapsular space, and the other advances as far 
as the central capsule. The nerve has the double 
contour as far as r, where it enters the central cap- 
sule; from that point it is pale and faint. This 
Specimen represents an offset of the central cavity, 
and of the pale nerve at s. The stem continues its 
course, ¢, towards the further end of the central 
cavity, while the offset follows the curved axis of 
the subordinate cavity as far as v, where it ends in 
a bulb by which it is fixed. Several of the cap- 
sules are united together at x. Magnified about 
diameters. 
surface exhibits very faintly marked elongated 
nuclei, which most probably belong to the wall 
of the inner capsule. 
There is little to add to the description of 
the nerve-tube already given. It is faintly 
granular in texture, and occasionally regains, at 
879 
one or more points-of its course within the 
central capsule, the dark contour which it had 
lost on entering it. This is particularly the 
case when it follows a bend of the cavity, and 
certainly seems to indicate the presence there of 
a material elsewhere deficient. It is rare, how- 
ever, to see this re-assumption of the dark 
border in any very well-marked degree. The 
mode of attachment of the end of the nerve- 
fibre varies, being generally by a single tubercle 
or conical swelling, sometimes by two, and 
sometimes even by three such. Whatever the 
number of branches, however, their aggregate 
thickness is about the same as that of the simple 
fibre from which they spring. Where the cen- 
tral cavity exhibits the offsets above-mentioned 
the pale nerve-fibre is also invariably branched, 
its subordinate branch always traversing the 
axis of the subordinate cavity, and being regu- 
larly fixed at its extremity. It is interesting to 
observe how accurately the nerve-fibre preserves 
its place in the axis of the central cavity, how- 
ever abruptly that may be bent or branched, a 
fact which might be supposed to indicate some 
degree of viscidity in the clear substance through 
which it runs. 
Respecting the function or use of the Paci- 
nian corpuscles no satisfactory account has yet 
been given, nor even a plausible explanation 
offered. Their presence in so great abundance 
on the nerves of the palm and sole, and their 
absence from motor nerves, suggests the ob- 
vious enquiry, whether they may not be con- 
nected in some way with the sense of touch, or 
at least with the function of sensation, to which 
the fact of their concentration in such numbers 
in the splanchnic nerves of some animals as 
obviously answers in the negative. Undoubt- 
edly, however, we may anticipate much from a 
more extended research into their connections 
with the several parts of the nervous system in 
man and animals, than the very recent date of 
their disvovery has yet allowed. The specu- 
lation that they may be concerned in the pheno- 
mena of what is called animal magnetism is 
not to be passed over with contempt, if only 
because it has been hazarded by their distin- 
guished discoverer, Pacini, who, in common 
with many other unprejudiced and not inca- 
pable observers, is inclined to believe in the 
reality of some of the less marvellous effects 
which popularly pass under that title, such, in 
particular, as the mesmeric somnolence and 
catalepsy. Yet so vague an hypothesis, per- 
haps, barely deserves to be placed in juxta- 
position with the descriptive anatomy of the 
corpuscles. 
t will be more to the purpose to institute a 
brief comparison between these bodies and the 
electrical organs of the torpedo, a description of 
which will be found under the head of ANIMAL 
Exectricity. Since that article was written, 
however, further researches, and especially 
those of Savi,* have added some points of im- 
portance which it will first be necessary to no- 
* Savi, Etudes Anatomiques sur le systéme ner- 
veux et sur l’organe électrique de la Torpille. Vide 
Matteucci, Traité des phénoménes electro-physiolo- 
giques, Paris, 1844, . 
