24 
CiACCiOj on the Distribution of 
nection with the uncleated corpuscles, bat I have always seen 
the finest nerve branches to unite with one another. 
3. On the nerve-fibres distributed to the capillary vessels. 
When the finest arteries and the capillaries distributed to 
the skin of the frog are closely examined, they are seen to 
be loosely surrounded by a certain amount of connective tissue, 
which forms to them a special covering or sheath. This 
sheath is better defined and more distinctly seen in the smallest 
arteries and in largest capillaries than in the finer ones. 
When a bundle of dark-bordered fibres passes close by a capil- 
lary vessel, it very often happens that their respective sheaths 
mix so intimately together as to form only one. In the 
sheath just referred to nerve-fibres may be readily discerned, 
which are found to vary both in number and size in each 
capillary. These fibres exactly resemble those which branch 
out from the sheath of the dark-bordered fibres, and, like 
them, present, at irregular distances, spindle-shaped swellings, 
which are coloured by carmine. As I have already remarked 
with regard to the bundles of dark-bordered fibres, so in the 
capillary vessels, what appears to be the limit of the sheath, 
very often is found to consist of two or more fine nerve-fibres. 
Again, what seems to be, at the first sight, the nucleus of the 
sheath itself, on closer observation, is found to be one of those 
spindle-shaped swelhngs before alluded to. It is frequently 
observed that some of the fibres contained in the sheath of 
the capillary vessels, here and there, diverge from it ; but after 
running for some distance they return into the same sheath 
at some other point. But oftener some fibres, after leaving 
the sheath, are seen to pursue a long and tortuous course, 
passing through several meshes of the capillary network. 
These fibres, during their course, are seen to divide and sub- 
divide, and the resulting branches exhibit at intervals 
spindle-shaped swellings, and are connected with some very 
small bodies usually triangularly shaped, which, besides gra- 
nular matter, contain a larger granule in the middle. From 
these bodies nerve-fibres are seen to proceed in three difi'erent 
directions, some of which are distributed to the capillaries, 
while others unite with fibres derived from the sheath of 
other capillaries, or from the sheath of some bundles of dark- 
bordered fibres. In this case a nervous plexus with meshes 
varying in size and shape is produced, which sometimes is 
situated in the connective tissue between the meshes of the 
capillary network, and at others lies on two or more capilla- 
ries. 
