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

32 INJURIES OF NERVES.
results of nerve lesions, or may be caused after partial
nerve lesions by reflex influences originating in the wound.
1^0 matter bow caused, tbe}^ are limited to too large or
too small a supply of blood, or to alternations of these
conditions.
To test the probabilitj' of the competencj-of vaso-motor
lesions which follow wounds
changes to cause the m ultiplied
of the nerves of the limbs, we naturally turn to the simpler
case of injuries of the sympathetic in the neck.
Section of tliis nerve merely increases the amount of
blood which flows in any given time through the tissues
in which it is distributed, and also causes a rise in their
temperature. But these changes are not permanent, and
neither do we find that the face, for example,
is then
subject to spontaneous inflammations or to other trophic
alterations unless the animal be in bad health. Thus, in
rabbits long kept confined, I have frequently seen inflammation
of the conjunctiva and cornea follow such sections,
but not in their more vigorous companions, and such was
also Bernard's experience.
Moreover, artificial lesions in
the latter class appear to heal with unusual celerity.
Like Weber, I have.made man}- attempts to bring about
trophic changes in the face by irritating and partially
wounding the sympathetic, but my efforts have uniformly
failed ;
nor have like experiments, such as Lister's, upon
the sympathetic nerves in the limbs of the frog, been any
more fortunate.
Of course, section of these nerves in their course through
the compound nerves of the limbs of man is not without
indirect influences on the life of the tissues, but unhappily
we need as yet early thermometric observations after
nerve wounds of the extremities to complete their history.
In speaking of the eflect of nerve wounds on temperature,
I shall again approach this subject. At present
it is
only necessary to say that at remote periods after total