r the
right or the left carotid, there would ensue atrophy of one side of the
brain, and consequently paralysis of half the entire body; but it is
possible that in time there would come about a secondary circulation
from the other side of the brain, and thus restore a healthy condition.
Or the clot (which, in passing always from larger arteries to smaller,
must unavoidably find one not sufficiently large to carry it, and must
lodge somewhere) may either necessitate amputation of one of the four
limbs or lodge itself so deep within the body that it cannot be reached
with the knife. You are beginning to realize some of the dangers which
await you."

Arnold smiled faintly.

"But we shall do our best to prevent the formation of a clot,"
continued Entrefort; "there are drugs which may be used with effect."

"Are there more dangers?"

"Many more; some of the more serious have not been mentioned. One of
these is the probability of the aortal tissues pressing upon the weapon
relaxing their hold and allowing the blade to slip. That would let out
the blood and cause death. I am uncertain whether the hold is now
maintained by the pressure of the tissues or the adhesive quality of
the serum which was set free by the puncture. I am convinced, though,
that in either event the hold is easily broken and that it may give way
at any moment, for it is under several kinds of strains. Every time the
heart contracts and crowds the blood into the aorta, the latter expands
a little, and then contracts when the pressure is removed. Any unusual
exercise or excitement produces stronger and quicker heart-beats, and
increases the strain on the adhesion of the aorta to the weapon. A
fright, fall, a jump, a blow on the chest--any of these might so jar
the heart and aorta as to break the hold."

Entrefort stopped.

"Is that all?" asked Arnold.

"No; but is not that enough?"

"More than enough," said Arnold, with a sudden and dangerous sparkle in
his eyes. Before any of us could think, the desperate fellow had seized
the handle of the stiletto with both hands in a determined effort to
withdraw it and die. I had had no time to order my faculties to the
movement of a muscle, when Entrefort, with incredible alertness and
swiftness, had Arnold's wrists. Slowly Arnold relaxed his hold.

"There, now!" said Entrefort, soothingly; "that was a careless act and
might have broken the adhesion! You'll have to be careful."

Arnold looked at him with a