English scientist who had much to do with its various
methods, tells us that "the instauration of general anaesthesia came
from experiments on man alone; there is no suspicion of any experiment
on a lower animal in connection with it"; and Professor Bigelow, of
Harvard Medical School, as we have seen, makes the same statement.

The extent to which insensibility may be carried depends entirely on
the amount of the vapour inhaled. Suppose the quantity to be very
small. Then the result will be a diminished sensibility, without
entire loss of consciousness. Let the quantity inhaled be
considerably increase, and we may produce a profound stupor with
muscular relaxation, the eyes are fixed, and the eyelids do not
respond when the eyeball is touched. There is now deep anaesthesia,
and complete unconsciousness to the surgeon's knife. The borderline
between life and death is not distant; and if still more of the
anaesthetic is administered, we may reach a condition from which there
is no awakening. The skill of the anaesthetist is not unlike that of
a pilot, who needs to know just how far the ship may be steered in a
difficult channel without running upon the rocks.

For a slight operation, a very little of the drug will often suffice.
In some hospitals abroad--and perhaps in America--it is the custom not
to give anaesthetics to charity patients when the pain is not greater
than the extraction of a tooth. Between a light anaesthesia and the
deep insensibility required for some capital operation, THERE IS EVERY
CONCEIVABLE DEGREE. We see the same thing in ordinary sleep. The
deep unconsciousness of a thoroughly exhausted man is vastly different
from the light slumber of an anxious mother, who is aroused by a word
or touch. Yet both conditions are what we call "sleep."

Now, one of the popular delusions regarding what is called
"anaesthesia" arises from ignorance of its innumerable degrees. We
are told, for instance, "anaesthetics were used" in certain
vivisections. That assertion alone, in a majority of cases, will
quiet any criticism. If "anaesthetics were used," then the average
reader assumes that of course there was no pain. The experimenter may
know better. But if ignorance persists in misinterpreting statements
of fact, it is possible that he may think he is not obliged to make
the truth plain, to his positive disadvantage. If such method of
reasoning ever obtains, it may explain very much.

And yet it w