Nerves to the Skin of the Frog, 
21 
the dark-borclered fibres and the outlines of the sheath. I 
have very often found that the apparent outlines of the sheath 
usually consist of two or more of these fibres blended to- 
gether^ and the spindle-shaped swellings,, which are generally 
believed to be the proper nuclei of the sheath, in most in- 
stances, pertain to the fibres just alluded to exclusively. 
In the inner layer of the derma, where, as has been stated, 
the dark-bordered fibres form a very complicated network in- 
terwoven with that of the capillaries, very frequently may be 
distinctly seen two or more fine fibres, leaving, at intervals, 
the sheath of the bundles of the dark-bordered fibres some- 
times at acute, and sometimes at right angles. These fibres 
which usually come out from diff'erent parts of the sheath, im- 
mediately after blend into a single bundle ; and so intimately 
mingled together are the individual fibres in the bundle, that 
it appears to be not a compound, but a larger single fibre. On 
following some of these bundles throughout their course, they 
are seen to divide and sub- divide, and at the point where the 
division takes place are sometimes found triangularly-shaped 
swellings, which contain fine granular matter, and a large 
granule seated either in the centre or at one of the angles. 
The granule, which is either oval or spherical, is alone coloured 
by carmine. When that occurs, it is always observed that the 
originary bundle is connected with one of the angles of the tri- 
angular swelling, while from the remaining angles spring two 
smaller bundles, which pass in different directions. The second- 
ary bundles (either they are derived from the simple division of 
the primary one, or from the two angles of the swelling just 
mentioned) , on reaching a capillary vessel, one of them is seen 
to pass over it, while the other divides into two branches. Of 
these two branches one is frequently observed to cross the 
capillary more or less obliquely, and the other to enter its 
sheath, and to run parallel to it. The branches into which the 
primary bundle divides, present, at inequal distances, spindle- 
shaped sAvellings, which are sometimes also found in the origi- 
narybundle before the commencement of its division. Respect- 
ing those branches, which I have said to pass over the capil- 
lary vessel, they are seen after a long and tortuous course to 
ramify in the same way over distant capillaries. 
When a bundle of dark-bordered fibres happens to pass 
near some of the capillaries, to which are distributed the 
branches resulting from the division of ^the bundles above 
mentioned, it is not unfrequently observed, that from the 
bundle of the dark-bordered fibres two or more fine fibres 
issue, which divide into branches, which unite with those 
derived from the division of other bundles, and thus a plexus 
