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

46 INJURIES OF NERVES.
evidence in its favor through the recent experiments of
Vulpian and others.
To settle the question, MM. Vulpian and Phillipeaux
cut across the hypoglossal (motor nerve of the tongue) ;
the central portion was then plucked out with its hulbous
roots, next the pneumogastric wasin like manner divided,
and a long piece of the peripheral end excised, after which
its central end was brought by suture in contact with the
peripheral end of the cut hypoglossal.
A post-mortem inspection after four months showed
complete union and restoration of the neural integrity ;
but, previous to this examination, pinching of the central
parts of the pneumogastric caused free movements of the
tongue; there was, therefore, perfect communication of
excitations from the central end of the pneumogastric to
the peripheral end of the hypoglossal. The effect was
the same when the pneumogastric had been divided a
little
way above the line of union what remained of the
;
nerve was still able to conduct impressions to the muscles
of the tongue, and under this modihcation of the experiment
all possibility of deception through reflex action was
cut off.
In like manner, when to the peripheral end of the pneumogastric
is united the central end of the hypoglossal,
irritations of this latter nerve influence the heart's movements.
In these instances it is clear that the impressions
passed in directions exactly the reverse of those which
they would usually follow, if the original function of the
nerve determined and limited the direction possible to
nerve force. Still more decisive are the cases in which
the lingual
are united ;
nerve (sensitive) and the hypoglossal (motor)
for here it was possible, according to the mode
of union, to excite motion through a sensitive nerve, or
sensation through a motor nerve.
There is, then, as Vulpian states, no histological distinc-