REGENERATION OP NERVES.
129
related by Mr. Earle* § in which a part of the ulnar nerve had been
cut out, and in which, in consequence, the little finger at the end of
five years was still useless, and the sensations in it very imperfect.
In the great majority of Arnemann’s experiments, the lower portion
of the nerve was quite insensible one hundred and even one hun¬
dred and sixty days after its division.
Among the most remarkable experiments on the reproduction of
nerves are those of Haighton, Prévost, and Tiedemann. Haightont
divided the nervous vagus on one side of the neck in a dog, and
three days afterwards divided that on the opposite side; the dog died,
as when both nerves are divided at the same time. In a second dog
he divided the second nervus vagus nine days after the first; the dog
lived thirteen days. In a third, the nerve of the one side was divided
six weeks after that of the other side; the dog remained in a weak
state for six months, but lived; at the end of six months the voice
had returned, and the tones had become higher. Nineteen months
after the nervi vagi were first divided, Haighton again divided both
nerves one after the other; the animal died on the second day.
Richerand repeated these experiments of Haighton with different
results. Breschet and Delpech also deny that the nervous substance
is regenerated.;); Prévost, on the other hand, has confirmed Haigh-
ton’s experiments; he repeated them on new-born kittens.
In another series of experiments, the proof of the reproduction
of the nerves consists in the restoration of the power of motion in
limbs, the nerves of which have been divided. From most experi¬
ments of this kind no inference at all can be drawn, unless, as in
Tiedemann’s case, all the nerves of the limb have been divided.
Schwann§ has made many experiments to determine the result of
division of the ischiadic nerve in rabbits, from which, however, no
certain conclusion can be deduced. The nerves distributed to the
muscles of the thigh come off from the ischiadic plexus and the
ischiadic nerve very high up, and are likewise in part derived.from
the crural and obturator nerves; so that division of the ischiadic
nerve in the middle of the thigh, and even higher, paralyses merely
the muscles of the leg and foot. Although the animals, therefore,
will not be able to step perfectly with the foot in such a case, still
they will be able to use the leg from the action of the muscles of the
thigh being unimpaired.
Too much importance had been attributed to Nysten’s experi¬
ments, || which showed that, in persons who had died some days after
an apoplectic atfack, the muscles still retained their irritability—
contracted on the application of galvanism,—although the brain had
lost its influence; for, in the experiments which I have made with
Dr. Sticker, we found that, although the lower portion of a divided
* Med. Chir. Transact. 7.
" Mem. Med. Soc. v. iii. Reil’s Archiv, ii. 80.
X Lund, Vivisectionen, 218.
§ On the Treatment of local affections of the Nerves, London, 1820, translated
into German by Francke. Leipz. 1824.
1| Nysten, loc. cit. p. 369.