aken away from the
lungs, as well as warmth to be added. This woman's extreme coldness, and
feeble, fluttering pulse, showed that she was dying for want of right
breathing; and in her case there was no doubt that the cause was the
same as that of death by drowning. The carbonic acid gas which she had
inspired, being heavier than atmospheric air, settled as water in her
lungs, and in the same manner prevented the access of oxygen to their
living tissues. And hence arose the reflection that the ordinary
carbonic acid gas, which is always the residuum of respiration, might,
from weakness, settle in the lungs, and thus become the cause of disease
and death. The presence of carbonic acid in the lower bronchial tubes
and cells, existing in quantities sufficient to prevent the natural
combustion by breathing, was brought to my mind in March, 1847, while
searching for the cause of an agonizing paroxysm of sick headache. The
distressed feelings of obstructed life with which I was tossing and
struggling, together with the agonizing pain in the head and pressure on
the stomach, might well arise from such a cause. Standing (for position
is important) in a full current of air from an open window, I commenced
a species of violent artificial breathing, for the purpose of ejecting
the supposed heavy gas, and filling my lungs with pure air. This was
done by contracting the chest on every side to its smallest possible
dimensions, and at the same time throwing out the air violently and from
the bottom of the thorax, as if under the operation of an emetic; then
alternating by opening the chest to its greatest capacity, and drawing
in, by successive inhalations, all the fresh air possible, and pressing
it down to the lowest depths of the lungs. This process at first gave
such intensity and sharpness to the pain in the head, that it required
much resolution to continue it; nevertheless it was persevered in. After
a few minutes, the pain diminished, and soon entirely ceased. This was
followed by free perspiration, and equalized, warmth and circulation.
Perfect repose and quiet sleep ensued. Friends, who a short time before
had seen a countenance like that of a dying person, and knew how slow
was ordinary cure, were astonished, an hour afterwards, to behold, on my
awaking, the full glow of restored health.[6]

On the re-appearance of cholera, during the summer of 1849, my mind was
peculiarly affected, from the belief that a false theory of circ