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

NEUKO-PHYSIOLOGY. 35
directly and originally upon the parenchyma of the tissues."
In 1860, Samuel,* resting upon facts such as I
have urged in regard to the vaso-motor nerves, rejected
them as the sole causes of nutritive changes, and declared
his theory of trophic nerves as distinct fibres concerned in
governing the nutritive conditions of the tissues.
This observer conceived that the trophic nerves have
their centres in the intervertebral spinal ganglia, or in
cerebral ganglia having like physiological powers. He
distinguished them as centripetal nerves, receiving and
conveying inward impressions connected with trophic
changes; and centrifugal nerves which, when palsied, give
rise to atrophies, and, when irritated, to inflammations.
Thus, while he regards nutritive activity as the result
of a force inherent in the molecules or cells of the tissues,
he looks upon the trophic nerves as the means of regulating
their changes, increasing, retarding, or enfeebling
them, as the case may be.
The experiments on which he chiefly bases this hypothesis
have failed in the hands of other observers, and as yet
there is no absolute physiological proof of the existence
of such nerves. The anatomical demonstration of these
fibres is equally wanting, so that at present the justification
for their existence lies in an apparent necessity for
their presence which so impressed Duchenne as to cause
him to remark that "if we had no knowledge of such
nerves, we should be forced to invent them."
If, in fact, we exclude vaso-motor influence as capable
alone of explaining the pathological changes which follow
nerve wounds, we are forced to fall back upon the nerves
of motion and sensation, or to believe in a system of
independent trophic nerves. The discovery by Biirensprung
of inflammation of the intervertebral ganglia of
* TropMschen Nerven. Leipzig, 1860.