30 
CiACCio^ on the Distribution of 
terior roots of the spinal nerves between tlie ganglion and the 
cord. It is evident^ therefore^ that in such conditions of ex- 
periment no disorder of nutrition should be expected to take 
place^ as the spinal ganglion had been preserved uninjured. 
As to the single experiment in which, at the same time, were 
cut several posterior roots of the spinal nerves, and three 
ganglia removed, I should remark that the animal on which 
the experiment was made, died two days after. The period of 
time was, therefore, too short for allowing the nutritive dis- 
orders to take place. It is very probable that had the animal 
lived longer the signs of impaired nutrition would have mani- 
fested themselves. What has just been remarked is strongly 
supported by the fact that the nutritive disorders which follow 
the section of the fifth nerve are not unfrequently seen to 
take place some days after experiment. 
The effects which follow the division of a compound spinal 
nerve resemble, in a certain degree, those which are observed 
after the section of the fifth nerve. Schifi","^ on experimenting 
on several animals, has found that the division of the sciatic 
nerve always induces dilatation of the capillaries, and an in- 
crease of temperature in the lower member. 
I am perfectly aware that I have only made an attempt to 
solve the two questions which I proposed at the beginning of 
this part of my paper ; but I hope that I may be able, in a 
future communication, to bring before the Society further and 
more conclusive observations on this important subject. 
I conclude this paper with the following inferences, which, 
in my opinion, are justified by the anatomical facts which 
have been described : — 
1 . In the skin of the frog are distributed two sorts of nerve- 
fibres, namely, the dark-bordered and the fine fibres, which run 
in the same sheath with them or with the capillary vessels. 
2. The dark-bordered fibres are so arranged as to form two 
networks ; one is seated in the inner, and the other in the outer 
layer of the derma. These two networks are connected by 
intermediate bundles, or, in plainer terms, the originary 
bundles of the nervous network in the inner layer of the 
derma, after its formation, pass off, crossing the middle layer 
more or less obliquely, and when they arrive at the under 
surface of the outer layer of the derma, there they branch 
again and form a second network. Continuous with this 
second network there is an intricate plexus, composed only 
of fine bundles of pale fibres, which are partly prolongations 
* " Untershungen zur Physiologie des Nervensystems mit Beriich sicli- 
tigung der Pathologie." Trancfurt am Main, 1855. 
