CHEMISTRY.
On the. changes which Ether, .Alcohol, and bodies of a similar con-
stitution, suffer when taken into the Cirulation. By Charles W.
Wright, M. D., of Cincinnati.—The rapidity with which certain sub-
stances manifest their action when taken into the circulation, has often
engaged the attention of medical men, and more especially so since the
discovery of the remarkable anaesthetic properties of the ethers, naphtha,
and chloroform.
It is observed that when a medicinal substance is inhaled, much less
is required to produce its characteristic effects than when it is admin-
istered by the mouth ; and it is often stated that therapeutic agents
operate quite differently when taken into the stomach, from what they
do when inspired. This difference seems to be more apparent than
real, as I think a thorough examination into this subject would plainly
show ; and if there be a difference, it is more in degree and rapidity
than in kind.
Ether and alcohol are the first that will be considered under this
head.
The first effect of the inhalation of the vapor of ether is to stimulate
the system powerfully, but this state of excitement soon passes off, and
is rapidly succeeded by a lethargic condition of the system, the skin
becoming cold and pale, lips of a livid hue, slow and laborious respira-
tion, in fact coma supervenes, and this in from two to five minutes.
Introduce the same substance, but in larger quantity, in the liquid form,
into the stomach, and what then occurs ? w’hy the same train of symp-
toms precisely, but which are much slower in making their appearance,
and which are protracted a greater length of time. That it should re-
quire a larger quantity of ether to produce these effects through the
medium of the stomach than the air passages, is obvious, for when ether,
in the form of vapor, is enhaled, being exposed to a great extent of
absorbing surface, it passes at once into the circulation, and there meet-
ing with oxygen in a very active form, enters into combination with it,
forming carbonic acid and water, being attended at first with excitement
which retards the supervention of coma. The combustion of the ether
is very rapid at first, but as the oxygen is consumed it fails to perform
its task of purifying the blood, the consequence of which is, carbonic
acid accumulates in that fluid, and death is finally brought about in pre-
cisely the same manner as if the patient had in the first instance inhaled
carbonic acid gas. The impression which I wish to convey may be
illustrated by comparing the inhalation of ether to the common experi-
ment of plunging a lighted taper into a vessel of oxygen gas. In that
case the combustion begins with great energy, but the flame grows less
and less, until it is finally extinguished. Now there are two causes in
operation tending to retard and ultimately arrest the combustion in
this experiment; the first is the gradual disappearance of the oxygen
from the vessel in which it is contained, the second is the influence
which carbonic acid exerts in diminishing the combustion going on in
flame.
The excitation of ether, when first administered, is very rapid ; but
as carbonic acid is generated in proportion as it is consumed, and the
blood in other respects fails to be decarbonized, the excitement is soon
succeeded by lethargy, the person dying as if poisoned by carbonic
acid ; the symptoms and post-mortem appearances being the same in
both cases. In the former, the poison is formed by combustion going
on in the system, but in the latter it is formed out of the system and
inhaled.
The arrest of the circulation is not unlike that which results from the
respiration of nitrous oxide gas, but from a different cause. When the
exhilarating gas is inhaled a considerable length of time, the pulmonary
capillaries no longer have an attraction for venous blood, it being satu-
rated with oxygen. Carbonic acid produces just the opposite-state, by
charging the blood throughout the body with carbonicjicid, and des-
troying the attraction which the systemic capillaries have for the blood
in the arteries. Great irritability is induced by the former substance,
and the heart continues to pulsate even after the circulation in other
respects has ceased.
When taken into the stomach ether produces the same set of symp-
toms, with this difference, that the stage of excitement lasts longer, and
if the quantity taken be not too large, gives the system time to throw it
off in the form of water and carbonic acid. Even here, however, if an
overdose be swallowed it may prove fatal, the symptoms being the
same as when it is respired.
The symptoms ocasioned by the introdution of alcohol into the cir-
culation, are much the same as those produced by ether. This will
appear evident when we look at the composition of these two bodies.
Alcohol is represented by the formula C4 H5 4-0 0. Ether has the
same constitution, C4 H5 4-0, minus one atom of water, II O.
When consumed, they both yield the same products. That of
ether 12 O 4- C4 H5 04 = C Oa 4-5 II 0. That of alcohol 12 0 4- C4
Ils 0 4-II O4- = 4 C 02 4-6 H 0.
Naphtha has been used as an anaesthetic agent, and it probably operates
on the same principle, but from its producing a very rapid and fluttering
pulse, its employment is not considered safe.
Carbonic oxide produces a pleasing delirium before it narcotizes, if
gradually introduced into the lungs ; but cases of poisoning with this
gas are exceedingly rare.
That there are other influences operating here, I do not pretend to
deny, but that the characteristic effects of these agents are produced in
the manner set forth, I think a thorough examination of this subject in
all its bearings would not fail to show.—Western Lancet.