This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
The operation of alcohol as a stimulant is probably dynamic, that is, the result of its influence on the vital properties of the tissues, and independent of any chemical action exerted upon those tissues. At least, we have as yet no proof of chemical change produced in the organs which it stimulates; and all theories based upon such a change are, in the present state of our knowledge, conjectural. It is true that, in its more concentrated form, its affinity for water, and its disposition to coagulate albumen, may cause disorganization of the tissues, as any other chemical escharotic may do; but this is not its ordinary medicinal operation, to procure which it is always given much diluted. The theory that the excitement it occasions is a vital reaction against its chemical affinities, is, therefore, gratuitous. It may possibly be true; but we have no proof of it; and the safest conclusion is that, like any other stimulant, it produces its characteristic effects simply through its relation to the vital properties, which determines that, when it is brought into contact with the living tissues, these should take on an increase of action.
Its first effects on the brain may possibly result, in part at least, from the sympathy of that organ with the stomach. Indeed, so close is this relation, that any strong impression in one is very apt to make itself sensible in the other. The fact stated by Orfila, that alcoholic liquors act with less energy when injected into the cellular tissue than when taken into the stomach, seems to favour this view. But, whether the cerebral effects have or have not their commencement in sympathy with the gastric impression, they are chiefly attributable, throughout their course, to the direct action of the alcohol circulating through the brain. That this principle is absorbed, when liquids containing it are swallowed, is beyond all doubt. Its rapid disappearance from the stomach, and its odour in the breath are sufficient proofs of the fact. But it has been found also in the urine, bile, liquors of the serous cavities, brain, liver, and the blood itself; and especially abundant in the brain, in the ventricles of which it is asserted sometimes to have existed in an inflammable state. Dr. Ogston in one instance "found about four ounces of fluid in the ventricles, having all the physical qualities of alcohol" (Pereira's Mat. Med., 3d ed., p. 1987); and, in another instance, while heating over a candle, three or four drachms of urine taken from the bladder of a man who was drowned while intoxicated, he observed that its vapour was set on fire by the flame. (Brit. and For. Med.-chir. Rev., July, 1855, Am. ed., p. 148 ) Coming then into direct contact with the nervous centres, the alcohol stimulates them into excessive action, and thus gives rise to the phenomena of excitement which characterize the early stage of its operation. Every excitation of a part is attended with an increased flow of blood into it, and the active congestion increases with the excitation.
By the continued operation of the alcohol, the congestion is continually increased in the cerebral centres, which, after their brief exhilaration, become disturbed, and at length embarrassed or overwhelmed, all through the direct and continued irritation of the same agent. Hence the intoxication and ultimate stupor which follow the primary excitement. But at length, the alcohol ceasing to act, the cerebral centres become depressed in proportion to their previous elevation; and general prostration of the system results. The wearing out of the excitability, the ultimate general debility, and the consequent degradation of the organs, resulting from long-continued intemperance, have been sufficiently noticed.
The influence of alcohol upon the brain has been ascribed to the altered and more highly carbonized state of the blood. Of this there is no proof whatever; nor except in the single fact of stupor, is there any resemblance between the effects of this substance and the condition of the blood referred to. From the experiments of Dr. Bocker, it would seem that alcohol diminishes the amount of the solid and fluid excretions by the urine, and the quantity of carbonic acid exhaled in respiration, without increasing the fecal discharges, the perspiration, or the loss of water by the lungs.* Hence it has been inferred that it lessens the rapidity of the normal disintegration of the solids, and consequently diminishes the general activity of the functions; for the measure of their activity is the quantity of effete matter thrown out of the system. Hence, too, the practical inference, that it enables the body to be sustained by a less amount of food. But these are conclusions much too large for the basis on which they rest. We need many more, and much more variously repeated experiments, before they can be justified. No facts of observation seem more obvious than that alcohol stimulates the functions of the stomach and brain to increased activity; that it for a time invigorates digestion, promotes nutrition, increases the action of the kidneys or the skin, according as it is directed to one or to the other, and elevates the intellectual and emotional functions. How it can effect all these ends, without a more rapid disintegration and renewal of the structure, is inconceivable to one who considers such disintegration as a necessary attendant of every vital action. That, when taken in excess, it will overwhelm and, in some measure, paralyze the functions after the first excitement is past, and that, in this way, it may on the. whole diminish the amount of the excretions; and that by the wearing influence of its long-continued abuse, the functions come at last to be in great measure prostrated, is readily intelligible. But that, during its stimulant operation, it should not promote a more rapid change of the tissues which it stimulates, is quite incompatible with the present views of the connection between the actions and the wear and tear of the system. But it is an undoubted fact that the habitual use of alcohol lessens the desire and apparent necessity for food; and it seems to be well proved, that a labourer can do a certain amount of work with less ordinary aliment, if freely supplied with beer or wine, than when water alone is allowed for drink. But this fact is explained, at least in the early stage of the action of alcohol, not by the diminished integral change in the tissues, but by the double fact, that it promotes the more perfect digestion of the food taken, and at the same time supplies food itself. If the usual amount of food is swallowed, alcohol favours its digestion and conversion into blood, and hence produces a plethoric state. This reacts on the stomach, diminishing the desire for food; and hence less is taken. But, as stated, alcohol is itself in all probability assimilated. What else becomes of it ? Assuredly, but a very small portion of that taken into the body leaves it unchanged. It is certainly decomposed in the system. If, as some suppose, it were merely oxidized into water and carbonic acid, there would be a vast increase of the excretions of these products by the lungs, which, from the experiments of Dr. Bocker and some others, would seem not to be the case. It is probably converted into some one or more of the proximate constituents of the body; and I am among those who believe that it may, through the agency of the vital forces, and in the presence of organized nitrogenous matter, be converted into any one or all of those constituents, excepting only the mineral. The one, however, which most obviously results, is oil; and this is often generated with great rapidity. It is not only visible in the increase of the adipose tissue, and in the promotion of obesity in certain individuals, but it exists also in abnormal proportion in the blood; and the oleaginous change is probably the first step of the conversion of alcohol into materials fit for organization. And why should not alcohol be capable of digestion ? It is generally admitted that many of the organic acids are so, as vinegar, citric acid, etc. Now, by a very easy change, alcohol itself is convertible into acetic acid. The inference seems to me inevitable, that it also is capable of being digested and assimilated. It is food, therefore, as well as a stimulant; and this view certainly best explains the plethoric condition, and increased weight and fulness of the body, often so strikingly observable under its use, while the amount of other kinds of food taken is diminished. But this fact in no degree justifies its abuse. The various evils to which its excess gives rise are neither Ies- - sened in themselves, nor do they constitute a less unanswerable argument against the abuse of alcohol, from the fact that it may contribute to the nourishment of the body. In opposing an enemy, it is useless if not dangerous to shut our eyes against his good qualities, and bad policy to put ourselves into a position in which we cannot avail ourselves of them.
* The experiments of Dr. Bocker hare been confirmed by those of Dr. Hammond, of the U. S. Army (See Am. Journ. of Med. Sri., xxxii. 313 ) It may be admitted that, in the long run, alcohol diminishes the metamorphosis of the tissues, as it does all the vital functions, through the diminution of excitability and the production of debility; but I cannot admit that this result takes place during its stimulant action; and, if the amount of excretion of all kinds be diminished, during its direct action, I should, as before stated, be disposed to ascribe the result to a more thorough appropriation and assimilation of the food, which prevent the useless portion of it that may reach the blood, from passing off in the shape of urea, the phosphates, sulphates, etc. (Note to the second edition).