IRRITABILITY. 
quelques jours, l’un a la premiere attaque et 
_Fautre a la seconde, le galvanisme a déterminé 
_ des contractions aussi fortes dans les muscles 
du coté sain que dans ceux du coté paralysé: 
__ les iris des deux cétés sont également contrac- 
_ tées.”” “ Cette propriété n’a été completement 
_ anéantie dans les organes musculaires des deux 
‘Sujets qu’environ 12 heures apres Ja mort; et 
on n’a observé aucune difference dans les mus- 
cles paralysés.”* 
__Legallois makes similar remarks, founded 
_ upon experiments made upon animals. He 
‘observes, “ M. Nysten a montré que dans 
les paralysies les plus completes, lirritabilité 
"Se conserve dans les membres paralysés tout 
aussi bien que dans ceux qui ne le sont pas. 
ai obtenu un résultat semblable d’un expéri- 
: que j'ai souvent répétée. Elle consiste 
@ détruire la moélle lombaire dans un lapin 
Phy de moins de dix jours ; il faut le choisir de 
_ eet Age, pour que la circulation ne soit pas ar- 
rétée, et qu’il puisse continuer de vivre. Quoi- 
_ que dans cette expérience, le train de derritre 
_ soit frappe de mort, et que ses nerfs ne puis- 
_ sent plus recevoir aucune influence de la mo- 
élle épiniére, Virritabilité s’y conserve, et l’on 
oa pendant fort long-temps, faire contracter 
es cuisses, en irritant les nerfs sciatiques. Il 
_ parait donc qu’il se fait dans toute l’étendue des 
_ nerfs une sécrétion d’un principe particu- 
lier.” + 
__ From these quotations from Nysten and Le- 
_ gallois we should be led to the conclusion that 
_ the muscles of paralytic limbs, in all cases of 
_ hemiplegia and of paraplegia, simply retain 
their irritability. From another series of ob- 
_ servations, made by philosophers equally worthy 
_ of our confidence, we should be led to an op- 
| posite conclusion. 
_ Some interesting experiments on this point 
_ have been recently performed by Professor 
_ Miller and Dr. Sticker. The former cele- 
_ brated physiologist observes,t “ It was known 
_ that, after the division of a nerve, the portion 
cut off from communication with the brain 
_ retains, for a certain time, its excitability; but 
_ the question, how far the continuance of the 
_ connection with the brain and spinal marrow is 
_ necessary for the longer preservation of the irri- 
_ tability of the nerves, and whether the muscles 
retain their irritability when their nerves no 
| seldom mooted. WNysten had asserted that the 
ia muscles of patients who died a short time after 
an apoplectic seizure preserved their irratibility, 
and contracted under the influence of the gal- 
i vanic stimulus, although the functions of the 
brain had been paralyzed. 
_ Thad good reasons, however, for believing 
_ * Recherches Physiologiques, 1811, p. 369; com- 
_ pare p. 377 and 419; and Cuvier, Histoire des 
a Beietnes Naturelles, tome i. p. 213. 
+ CBuvres de Legallois, éd. 1824, p. 23 and 24. 
_ $ See the excellent translation of the ‘‘ Handbuch 
der Physiologie,” by William Baly, M.D., vol. i., 
_ p- 631—633; and compare p. 663, 724, 727, 898, 
&c. and Grainger on the Spinal Cord, p. 96, 97. 
q 
37 
that, in such cases, the nerves retain their power 
only for a short time, losing it entirely after a 
longer interval; for, in experiments on the re- 
production of the nervous tissue in a rabbit, I 
had once observed, that the lower portion of 
the nervus ischiadicus, which I had divided 
some months previously, had lost all its exci- 
tability; and a similar fact had been before ob- 
served by Fowler. I have since performed, in 
conjunction with Dr. Sticker, new experiments, 
which have completely confirmed that suppo- 
sition. To prevent the regeneration of the 
nerves, and to withdraw more effectually the 
lower portion from the influence of the brain 
and spinal cord, a portion of the nerve (the 
ischiadic) was entirely removed. The experi- 
ments were made only on two rabbits and a 
dog; yet the results were so constant, that they 
are quite worthy of dependence. 
“ Eleven weeks after the division of the 
nerve in the first rabbit, it was laid bare in its 
course between the biceps and semitendinosus 
muscles. Contrary to expectation, and to our 
mortification, the continuity of the nerve was 
found to be restored. It was divided anew 
below the cicatrix ; and it is remarkable that, 
although the animal uttered a loud cry, the 
section excited no contraction of the muscles. 
The lower portion of the nerve was now ex- 
posed to the galvanic stimulus of a single pair 
of plates, was cut and pulled in every possible 
way, but not the slightest muscular contraction 
was excited. 
“* For the sake of comparison, the nerve of 
the opposite side was divided, when the animal 
showed signs of suffering the most severe pain, 
and violent muscular spasms took place; and, 
after the division, very slight irritation of the 
nerve itself, that is to say, of the lower portion 
of it, or merely of the muscles, excited strong 
twitchings, even after death. 
“« Ten weeks after the division of the nerve 
in the dog, the ends were found to be reunited. 
The experiment was performed exactly as in the 
rabbit, and the result, as to the effect on the 
nerve, was entirely similar: it had lost all its 
excitability; but the muscles still contracted 
slightly when stimuli were applied directly to 
them immediately after death: however, this 
remaining irritability was gone, while, in the 
muscles of the opposite leg, the strongest con- 
tractions could be excited. 
“« Five weeks after the nerve had been di- 
vided in the second rabbit, we proceeded to 
examine its state, and were the more interested 
on account of the short time that had elapsed 
since its division. The ends were not united ; 
they were somewhat swollen, and connected 
with the surrounding cellular tissue. In the 
other instances, the portion of nerve removed 
measured about four lines only; here its length 
was eight lines. No contraction of the muscles 
could be excited by irritating the nerve either 
mechanically or by a chemical stimulus, caustic 
potash, or by galvanism ; nor by irritating the 
muscle itself, aithough the rabbit had plenty of 
vital power. Qn the left side the muscles were 
found irritable, as in the other cases, both before 
and after death. 
