Injuries of nerves and their consequences - Reflex Sympathetic ...

42 INJURIES OF NERVES.
The experimeuts of Bernard, especially upon the recurrent
sensibility of the cranial uerves, seem to prove that
the sensitive fibres turn backward at diftereut points in
the nerve route to accompany the motor fibres all the way
to their proper root, and even into the spine itself. The
author named conceives that the most of these recurrent
branches are
derived from terminal anastomoses of the
sensitive and motor nerves. Concerning this point, there
is still some doubt, but the existence of this peculiar sensibility
of the anterior nerve roots is now regarded as au
accepted fact in science.
Gubler andBrown-Sequard have both suggested difi:erent
and ingenious explanations of the so-called
recurrent
sensibility, but neither are satisfactory so that no one,
;
as yet, has offered any competent explanation of the physiological
necessity for the arrangement in question. The
difficulty of so doing is not lessened by the fact that
recurrent sensibility does not exist in fishes, and that
Vulpian failed to detect it in the pigeon. I repeated
some years ago Bernard's experiments, and reached the
same conclusions as he has done. I failed, however, to
discover recurrent sensibility in the duck and the chicken,
notwithstanding every precaution to insure success, nor
was I more fortunate in our large chelouians (Chelonura
serpentina), which are admirably fitted to be the subjects
of such experiments.
Neurility and neural excitants.— Every stimulus capable
of acting on a nerve causes in it the development of the
nervous force, the true nature of which is
extremely
problematical. For a long time there has been a decided
tendency to regard this force as some form or manifestation
of electricity but
; just in proportion as we have come
to know more of the true relations of the latter force to
nerve tissue
has the probability of the identity of nerve
force and electric force diminished.