the medulla or the great centers
at the base of the brain are wounded by a bullet, instant
unconsciousness must result; with any other wounds involving the
brain-substance it will, with very great probability, result. But there
is a very broad area of uncertainty. Many instances have been recorded
in which the entrance of a small bullet into the anterior part of the
brain has not prevented the firing of a second shot on the part of the
suicide. Personally, I have not observed such a case, however. But,
aside from the injuries by the smallest missiles in the anterior parts
of the brain, we may speak with almost absolute certainty with regard
to the production of unconsciousness, for the jar to the brain from the
blow of the bullet upon the skull would produce such a result even if
the damage to the brain were not sufficient to do so.

"Many injuries to the brain from bullets of moderate size and low
velocity do not cause more than a temporary loss of consciousness, and
the subjects are seen by the surgeon, after the lapse of half an hour
or more, apparently sound of mind. These are the cases in which the
ball has lost its momentum in passing through the skull, and has
consequently done little damage to the brain-substance, excepting to
make a passage for itself for a short distance into the brain. It is
apparently well established that, in the case of the rifle-bullet of
high velocity, and especially if fired from the modern military weapons
using nitro-powders, and giving an enormous initial velocity to the
bullet, the transmission of the force from the displaced particles of
brain (and this rule applies to any other of the soft organs as well)
to the adjacent parts is such as to disorganize much of the tissue
surrounding the original track of the missile. Under these
circumstances a much slighter wound would be necessary to produce
unconsciousness or death than in the case of a bullet of low velocity,
especially if it were light in weight. Thus I have recorded elsewhere
an instance of instant death in a grizzly bear, an animal certainly as
tenacious of life as any we have, from a mere furrow, less than a
quarter of an inch in depth, through the cortex of the brain, without
injury of the skull excepting the removal of the bone necessary for the
production of this furrow. The jar to the brain from a bullet of great
velocity, as in this case, was alone sufficient to injure the organ
irreparably. In a similar manner I ha