e perpetual necessity of the mixture of oxygen gas with the blood in
the lungs evinces, that it must act as a stimulus to the sanguiferous
system, as the motions of the heart and arteries presently cease, when
animals are immersed in airs which possess no oxygen. It may also
subsequently answer another important purpose, as it probably affords the
material for the production of the sensorial power; which is supposed to be
secreted in the brain or medullary part of the nerves; and that the
perpetual demand of this fluid in respiration is occasioned by the
sensorial power, which is supposed to be produced from it, being too subtle
to be long confined in any part of the system.

Another proof of the stimulant quality of oxygen appears from the increased
acrimony, which the matter of a common abscess possesses, after it has been
exposed to the air of the atmosphere, but not before; and probably all
other contagious matters owe their fever-producing property to having been
converted into acids by their union with oxygen.

As oxygen penetrates the fine moist membranes of the air-vessels of the
lungs, and unites with the blood by a chemical attraction, as is seen to
happen, when blood is drawn into a bason, the lower surface of the
crassamentum is of a very dark red so long as it is covered from the air by
the upper surface, but becomes florid in a short time on its being exposed
to the atmosphere; the manner of its introduction into the system is not
probably by animal absorption but by chemical attraction, in which
circumstance it differs from the fluids before mentioned both of heat and
electricity, and of ether and essential oils.

As oxygen has the property of passing through moist animal membranes, as
first discovered by the great Dr. Priestley, it is probable it might be of
use in vibices, and petechiae in fevers, and in other bruises; if the skin
over those parts was kept moist by warm water, and covered with oxygen gas
by means of an inverted glass, or even by exposing the parts thus moistened
to the atmosphere, as the dark coloured extravasated blood might thus
become florid, and by its increase of stimulus facilitate its reabsorption.

Two weak patients, to whom I gave oxygen gas in as pure a state as it can
easily be procured from Exeter manganese, and in the quantity of about four
gallons a day, seemed to feel refreshed, and stronger, and to look better
immediately after respiring it, and gained strength in a sho