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

52 INJURIES OF NERVES.
states by cholera, where the fluids are rapidly expelled
from the system by purging and vomiting, until the blood
becomes thick and of almost tarlike consistency. It
seems not unlikely that the terrible cramps and pains
of this malady may be due to this condition of the fluids,
since in the individual nerve an excitation, resulting in
spasms, follows always the drying of its tissues.
Far more interesting are the neural phenomena which
occur from absolute diminution or loss of blood or from
the various degrees of excess of that fluid.
When from arterial emboli, or owing to the ligation of
a main artery, the blood is for a time cut off" from a limb,
its loss is followed in many cases by excessive pain, and
more rarely by cramps. As Vulpian has justly remarked,
the preponderance of sensory phenomena in these cases
is due to the fact that the organ of final reference for
irritations, the brain, is unaltered, whilst the muscles
suffer early a loss of irritability,
which deprives the motor
nerves of all means of expressing the excitations to which,
in common with the sensitive filaments, they are subjected.
Examples of the pain produced in a limb by tying its
great artery are familiar to surgeons but I believe the
;
phenomenon
is not a constant one. In a case of ligature
of the aorta by Mr. James,* the pain thus caused was
terrible, nor did careful examination of the body furnish
any explanation of the fact. It is at all events instructive,
as concerns the causation of neuralgia, to learn that the
lack of blood supply may be a condition productive of
such extreme torture.
As regards emboli in main arteries, I
do not think the
pain a constant symptom, but it is safiiciently common,
and in more than one case within my own experience, its
* Med.-Chir. Trans., vol. xvi. p. 17.