_Shewing the effect of the introduction of Air into an artery._
Seven or eight cubic inches of common air were injected gradually
into the crural artery of a large dog. A peculiar rustling noise,
depending upon the admixture of the air with the blood, accompanied
the operation. No particular symptoms followed; but after some minutes
the corresponding vein became distended with frothy blood, which moved
with difficulty, and became stagnant in the vessel. The whole limb
crepitated upon pressure, but no untoward symptom presented itself for
more than half an hour. An ounce of water, to which seventy drops of
medicinal prussic acid had been added, was now injected into the same
artery. This produced no apparent effect upon the constitution.
A quarter of an hour after, an ounce of saturated solution of nux
vomica was injected into the same vessel. This also was followed by no
particular symptoms. An hour after the first injection, half an ounce
of a weak infusion of tobacco was introduced into the same artery.
Excessive pain immediately followed, accompanied by great rapidity
of breathing. The animal now appeared as if he were going to die;
however, he slowly recovered, appeared giddy and inclined to vomit, and
kept himself in a continual state of restlessness. This condition was
succeeded by fever, accompanied by extreme sensibility of the limb, and
irregularity of the pulse. At the expiration of some hours, he appeared
better; the pulse became more regular and less feverish, but the leg
continued swollen, and extremely painful upon pressure. During the
night, the pain returned, indicated by howling and restlessness. There
were several evacuations of fæces and urine. The following morning,
there was great prostration with much fever, and apparent suffering.
The limb was slightly emphysematous, swollen, inflamed, and infiltrated
with serum.
On the following day, two ounces and a half of water, in which some nux
vomica had been boiled, were injected into the crural artery of the
opposite limb. The dog expressed no pain; but, at the expiration of
ten or twelve minutes, slight convulsive motions became evident, which
were gradually converted into violent tetanic spasms. The animal threw
himself backwards with his limbs extended, and died, after repeated
convulsive attacks, an hour and a half after the last injection.
_Post-mortem appearances._ On opening the body, _no unusual appearances
were observed in the limb_ upon which the last experiment had been
tried, but the opposite one was tumid and emphysematous, infiltrated
with a greyish red frothy serum of a fetid odour. _The small vessels
were obstructed by firm clots of blood._ The gall-bladder was greatly
distended; and the intestinal canal contained a quantity of yellowish
mucus.