The word anesthesia--meaning WITHOUT FEELING--describes accurately
the effect of ether in anesthetic dosage. Although no pain
is felt in operations under inhalation anesthesia, the _*nerve
impulses excited by a surgical operation still reach the brain_.
We know that not every portion of the brain is fully anesthetized,
since surgical anesthesia does not kill. The question then is:
What effect has trauma under surgical anesthesia upon the part
of the brain THAT REMAINS AWAKE? If, in surgical anesthesia,
the traumatic impulses cause an excitation of the wide-awake cells,
are the remainder of the cells of the brain, despite anesthesia,
affected in any way? If so, they are prevented by the anesthesia from
expressing that influence in conscious perception or in muscular action.
Whether the ANESTHETIZED cells are influenced or not must be determined
by noting the physiologic functions of the body after anesthesia has
worn off, and in animals by an examination of the brain-cells as well.
It has long been known that the vasomotor, the cardiac, and the respiratory
centers discharge energy in response to traumatic stimuli applied
to various sensitive regions of the body during surgical anesthesia.
If the trauma be sufficient, exhaustion of the entire brain
will be observed after the effect of the anesthesia has worn off;
that is to say, despite the complete paralysis of voluntary
motion and the loss of consciousness due to ether, the traumatic
impulses that are known to reach the AWAKE centers in the medulla
also reach and influence every other part of the brain.
Whether or not the consequent functional depression and the morphologic
alterations seen in the brain-cells may be due to the low blood-pressure
which follows excessive trauma is shown by the following experiments:
The circulation of animals was first rendered STATIC by over-transfusion,
and was controlled by a continuous blood-pressure record on a drum,