The chemist recognizes many different alcohols. The one we drink is called ethyl alcohol. Carbon, hydrogen and oxygen are its only chemical elements. They exist in simple combination to form a colourless liquid. Two linked atoms of carbon have five hydrogen atoms attached to form the ethyl radical. A hydroxyl (or alcohol) group completes the chemical molecule. In the diagram, C, H and O stand for single atoms of carbon, hydrogen and oxygen; —OH denotes the hydroxyl group.
Other alcohols can be made by adding or subtracting carbon and hydrogen atoms, but only the ethyl variety has the conventional effects of alcohol as we know them and only ethyl alcohol is safe to consume. Alcohol can be prepared easily from many plants and has been known to man from earliest times all over the world.
Although the chemist can make it from its basic constituents the alcohol we drink comes from fermentation by yeast of sugars that occur naturally in plants. The drinks produced by such fermentation, beer from barley, wine from grapes and cider from apples, are relatively weak in alcohol. Beer contains between z\ and 4I per cent alcohol by volume. Strong beers have as much as 8 per cent; ciders are roughly of comparable strength. Most wines contain between 10 per cent and 12 per cent of alcohol. The alcohol concentration may be increased subsequently by distillation, a process which produces spirits.
The strength of spirits is much greater. In Britain they generally contain between 30 per cent and 40 per cent of alcohol, more in the United States. Forty per cent is the usual strength in this country for gin and whisky (though some malt whiskies are stronger). Rum, brandy and vodka are of similar but more variable strength. The strength of liqueurs varies widely. The strength of spirits is generally recorded as so many ‘degrees proof’. This harks back to an old measure of the concentration of alcohol devised by the early distillers. Gunpowder mixed with water will not ignite but mixed with alcohol it will. If mixtures of alcohol and water are tried it is found that a combination of half alcohol, half water will allow the gunpowder to ignite but weaker concentrations of alcohol will not. The strength of the spirit used to be proved in this way. Proof spirit contains approximately 57 per cent of alcohol by volume; 70 degrees proof means that the alcohol content is about 40 per cent.
Some drinks are mixtures of ferments and distillates. Sherry, for instance, is a fortified wine, brandy being added to bring the alcohol strength up to 20 per cent.
No matter what beverage is drunk the alcoholic effect depends on the amount of alcohol consumed and not on the colouring, flavouring or any other constituents, though there is currently some interest in the independent effects of these other components of alcoholic beverages, known as congeners.
Alcohol exerts, according to its strength, an effect on the lining of the mouth, the oesophagus, the stomach and the upper part of the intestines. In the mouth this is experienced as a burning sensation, pleasant or slightly painful. The expression ‘that hits the spot! ’ well describes the stinging and the satisfying effects of a glass of spirits quickly drunk. From the stomach and intestines the alcohol is absorbed into the blood stream and passes rapidly into all the tissues and fluids of the body. Gradually it is destroyed by oxidation, principally in the liver, and it is eventually broken down into carbon dioxide and water. A small quantity, perhaps 2 per cent, escapes this process and is excreted in the urine and in the breath. The amount of alcohol breathed out is very small indeed, but it is sufficient to indicate the concentration of alcohol in the body. The smell on a drinker’s breath is imparted chiefly by other volatile constituents of drinks and is no index of the extent of intoxication. The rate at which alcohol is oxidized is independent of the concentration in the body; as the maximum rate is quickly reached it follows that it will take much longer for someone who has drunk very heavily to return to normal than it does for a moderate drinker. Four ounces of whisky or four pints of beer might take four or five hours to be oxidized and if the amount drunk is doubled it would take twice as long. For this reason people who drink slowly but continuously, though they may appear less incapable, take as long to recover from drinking as those who have absorbed a similar quantity rapidly.
The principal effects of alcohol are upon the nervous system but changes also occur elsewhere in the body. The heart rate may rise a little and there is an increased flow in the blood vessels resulting in flushing and a warm sensation in the skin. The rate of urine production rises, chiefly as a consequence of the amount of fluid that is drunk but also because alcohol influences the pituitary gland which controls the rate of urine formation.
Alcohol is a food. As a provider of calories it must, in Britain, be one of the most expensive, and certainly the most extensively taxed. It is a carbohydrate and because of its rapid absorption from the stomach it is a quick source of energy. However, this energy cannot be used efficiently because of the incoordinating and intoxicating effects of alcohol. Only the self-deceiving can believe they are doing something dietetically useful by drinking, except for stimulating the appetite.
Alcohol is supposed to be an aphrodisiac and to promote sexual function. It may stimulate desire, and the shy man or the cautious may, under its influence, be able to have intercourse because his inhibitions, his fears or his scruples have been lessened. However, this is a psychological effect. Upon potency alcohol exerts a dampening action.
The effect of alcohol upon the nervous system is to reduce its activities. All its functions are depressed. How is it, therefore, that alcohol has come to be widely thought of as a stimulant ? Unless we can resolve this paradox we shall never understand the use of alcohol by man.
Let us marshal the evidence for stating so categorically that it depresses activity in the nervous system. On the physical side it numbs like an anaesthetic so that a man may fall when drunk and not appreciate that he has hurt himself; it may send him to sleep; it may even make him unconscious. It alters the rhythm of brain waves recorded electrically from the head. Even in small amounts it affects speech and balance and impairs judgement. After a few drinks our ability to react promptly to a changing situation or an emergency is reduced, so that we ought not to drive a car. In ordinary social intercourse, at a party for instance, we can no longer so finely or so quickly assess what it is proper for us to say or to keep silent about. Here lies the explanation of the paradox. The first thing to be depressed is the power of restraint. The inhibition of our actions or our wishes which we all of us adopt in order to get on with our fellows is the product of the highest mental processes and it is these that are impaired first. When the curb we normally place on our instinctual urges goes, unguarded behaviour comes to the fore and these released impulses are forcefully expressed, giving the impression of stimulation. The solitary become gregarious, shy men loquacious and the fearful foolhardy. Self-critical men can treat themselves kindly, sexually inhibited men dare to be amorous. As our individual characteristics drop away from us attributes common to us all prevail. At first the increased press of talk and activity sets up smiles, gaiety, even boisterousness. Generally we retain enough self-control to keep these within bounds. Most social drinking never proceeds farther than this and the atmosphere produced is indeed stimulating. It is also infectious. In Sweden, for instance, where it is usual for one member of a party not to drink because he will be driving home, the communal laughter, affection and good spirits rub off on to him as well so that he shares in the general feeling of wellbeing.
But sometimes the drinking facilitates a group mood of dejection or of anger, and people have had their passions so inflamed by alcohol that they carried out cruel, senseless, irrevocable actions from which, if the highest mental processes were functioning intact, each individual would recoil with disgust. This, of course, is the extreme, but the morning-after reaction sometimes contains a sense of amazement and shame that one could have done the things one did so carelessly the night before.
These changes, which the physician and the physiologist call depression of the nervous system, begin with the first drink. There is not a level below which one can drink without any noticeable change but above which one is affected. Fine tests of discrimination, of memory, of driving skills all show that the impairment begins with the beginning of drinking and advances steadily with the continuation of drinking. We know too that a vicious circle is set up. The more we drink, the more our faculties and our judgement are lost, and consequently the less we appreciate this falling off of our skills. It is this which allows clearly incapable men to believe they are fit to drive. In a recent experiment1 bus drivers, after drinking different amounts, were asked to judge whether they could get their buses between two movable posts. As they drank more and more they became less
Accurate in deciding, but more certain that they were right. This is one reason why it is impossible to state an amount to drink or a blood concentration of alcohol below which it is all right to drive. For legal purposes an arbitrary level may have to be fixed but the truth is that some impairment occurs with any drinking, one small whisky, half a pint of beer. The drinker is in the worst possible position to make the decision whether he is safe to drive or not.
During a single episode of drinking a certain level of alcohol concentration in the blood will be achieved, and then as further drinking takes place it will be exceeded. Later on, as the drinker sobers up, the blood concentration will again pass the former level as it falls. But if we make psychological observations at two points in time when blood concentration is the same, one when it is rising and one when it is falling, we cannot fail to observe that he performs better on the later occasion.
Neither the amount that is drunk nor the blood alcohol level, therefore, can be absolute guides to a person’s capabilities.
Another reason why it is dangerous to lay down safe amounts to drink is that increased tolerance occurs in drinkers. This phenomenon explains why not all people who drink the same amount become equally intoxicated. Different people are differently affected by the same intake of alcohol. Some have more tolerance than others; that is to say, their efficiency is less impaired. An individual develops increased tolerance during the course of his drinking career; at the outset he will be much more affected, say, by six whiskies than he will be later on. Still later, especially if he falls sick or is undernourished, his tolerance may again decline. This accounts for the distressing experience of many advanced alcoholics that suddenly they become much more disorganized by an amount of drink which previously they could handle without difficulty.
During the process of acquiring tolerance the cells of the body become seasoned to alcohol so that a given concentration affects them less than it used to. No one knows how tolerance develops. It has nothing to do with the rate of absorption, metabolism or excretion of alcohol. All we can say is that the cells of the body, in particular of the brain, get used to functioning in the presence of higher concentrations of alcohol than they could tolerate before.