There is none of the inspired oxygen returned to the lungs by the
circulation. What becomes of it, or what its use within the system, has
not been written for our learning. It is not retained in the blood,
nor is it animalised; nothing yields less oxygen than animal matter.
To convey "carbon" out of the system, and somehow purify the blood, is
the supposed service; but if so, should it not be included in every
expiration and of the inspiration quantity? but which is not the case.
Harvey proved that the blood circulates, but left undiscovered what
keeps in motion the _inert_ fluid, except the systole, which the
_inert_ heart cannot effect on itself. No organ can do anything of
itself, the whole being composed of inert substance, and nothing else;
even the life of the body, whatever it may be, leaves the function of
every organ, not excepting that of the brain, dependent on the general
pressure.
By the general pressure the air is forced into, but not through or
beyond the lungs which it inflates, and inflates nothing else. Within
the blood-vessels it would prove fatal; and although from it the blood
derives that by which it becomes arterialised, yet the blood and air do
not come in contact, extravasation and pulmonary rupture must happen,
did the lungs permit the blood and air coming together, or in immediate
contact. Of the air of an inspiration, the oxygenating imponderable
element only can permeate the pulmonary tissue. This element it
is which imponderably arterialises the blood; the nitrogen of the
inspiration constitutes the immediate succeeding exspiration.
The oxygenating element promotes the circulation on the same principle
that it promotes combustion; its diminutive interstices exclude
electric matter, which coagulates, and admits the propelling force,
medium of space, which is the only cause of motion, to enter the blood.
The oxygenated blood being propelled, or pressed, by the medium of
space it includes, from the lungs into the ventricle, the collapse, or
systole, takes place, and the blood is forced out of the ventricle,
through the auricle, into the aorta, thence through the several
branches of the arterial system, to and through the capillaries, into
the veins. Thus, from the medium of space within the blood being
continuous with the medium of space generally, it is manifest that the
blood is circulated not by the systole, but by the general pressure. To
produce the systole, there is nothing but the normal pressure on the
outside surface of the heart; nor, to lessen the normal pressure on the
parietes of the ventricle, is there anything but the arterialising,
minus-pressure, imponderable element of the blood just received into
the ventricle.
Throughout the entire of the arterial flow, the blood is losing the
arterialising minus-pressure matter to the different organs, as the
means by which the functional action of each is promoted. Without
such means, there is nothing to disturb the equilibrium of pressure
on an organ to produce organic motion, action, or function. Hence, it
appears, that the use of the inspired oxygen consists in promoting the
circulation of the blood and the functional motion or action of the
different organs within the frame.
Before entering the veins the blood is fully deoxygenated; within
them it acquires gradually electric matter, productive of the livid
or coagulating appearance; at the same time the blood-propelling
medium is lessening in quantity; but which is compensated in the
mucilaginous lining of the veins, which assists the venous flow on the
minus-pressure capillary principle; capillary attraction would collapse
the vessels. The electric matter collected by the venous blood is got
rid of in the lungs, and expired with the nitrogen and a remnant of the
oxygenating element of the last inspiration; hence the small portion of
carbonic acid gas obtained from the expiration.
After all organic service, the arterialising minus-pressure matter
is insensibly transpired, which is inferable from the supply being
continued through respiration; which, although constant, yet, from
being intermitting, might, perhaps, cause corresponding stoppings in
the round of organic action; hence it would seem that, against such
intervals or interruptions taking place, the liver has been designed to
collect for casual distribution a portion of the same minus-pressure
matter. The great surface of the liver may stand comparison with the
plate, or cylinder, of the electrifying machine, and the organs as jars
which receive electric matter from it, as each stands in need.
_Use of the Spleen._--The SPLEEN, from being an organ common to
the human frame, must have an allotted service to supply; although
considered useless by some, to all of unknown utility, it may be _a
lateral channel of arterial blood direct from the heart, to supply the
vessels lying in a portion of the body not traversed by the arteries
belonging to the great arterial system_; those of the diaphragm
first; thence through the umbilical cord to the fetus, in which the
circulation is indispensable, from being the only means of conveying
and dispersing throughout the body, in the absence of respiration,
the minus-pressure matter which the organism of the fetus requires
to promote the several functions, without which life would become
extinct if commenced. In this supply of motion promoting elementary
matter, consists all that can be considered _aeration_ of the blood,
and all that the blood of both the fetus and the _adult_ requires,
or can possibly receive. In the chirping chick, while within the yet
unbroken shell, aeration is _prevented_ by incubation of the mother
bird; but the arterialising elementary matter is amply provided within
the larger, apparently empty, end of the shell. To keep out electric
matter, which would exclude the blood-moving medium, is the object of
the hen sitting on the eggs, and oven-hatching is effected on the same
principle.
_How the Diaphragm Is Raised._--The _diaphragm_ cannot rise of itself,
and has no self-acting, self-lifting nerves or muscles, all flesh being
composed of _inert_ atoms. The rise is proof positive that pressure is
greater on the posterior than anterior surface of the membrane, and the
unchanged normal pressure beneath indicates reduced pressure above; the
latter is promoted by minus-pressure matter imparted by the splenic
blood to the diaphragm, while passing through the vessels of the
diaphragm. This arterialising matter being highly evanescent, escapes
from the diaphragm and upwards, and during the escape mitigates the
pressure, intercepts it in some degree from the superior surface; then,
by the normal pressure beneath, the rise of the diaphragm is effected.
As the escape, or separation, is becoming complete, the equilibrium is
being restored, and the diaphragm depressed to the normal level. If
this be not the rationale of diaphragmatic motion, it will be little
improved by the substitution of muscular energy, leverage, or muscular
vitality, while leaving out _muscular inertia_, which should not be
omitted, but included, in accounting for every muscular action and
motion.