The term "alcohol" in popular language refers to the ethylic variety of the di-carbon series (C2H5OH). Alcoholic drinks, however, contain other substances besides alcohol, and the effects of these latter upon the human organism have to be taken into account as well as those of the alcohol itself.
Ethyl alcohol is obtained by the fermentation of grape sugar, whereof a single molecule yields two molecules of alcohol and carbonic acid respectively (C6H4206 = 2C2H5OH + 2CO2). During the process most of the carbonic acid escapes as gas, only a small part remaining in solution, but if the alcoholic solution is bottled up before fermentation is complete, a large amount of the carbonic acid may be held in solution, escaping with effervescence when the pressure is removed.
The grape sugar from which alcohol is derived is obtained from a variety of vegetable substances. The chief are grain (especially barley) and the grape, but numerous other substances are employed in its manufacture, including potatoes and even sawdust, the latter being converted into fermentable sugar by means of acids.
The discovery of alcohol probably does not date further back than the time when man first began to cultivate the vegetable kingdom for food. Certain it is that all extant pre-agricultural peoples were ignorant of it until they came into touch with agricultural man; while, on the other hand, practically all the early agriculturists - the red-skins of America, the negroes of the vast continent of Africa, the inhabitants of the numerous islands scattered throughout the Pacific - have long brewed alcohol, a fact not, we think, generally known.
The absence of alcohol among the pre-agriculturists cannot be explained by their lack of substances especially suitable for fermentation, such as barley, maize, and the grape, for apart from the fact that the uncultivated vegetable kingdom yields many fermentable materials, almost all the pre-agriculturists are abundantly supplied with honey, the source of that once so popular British drink known as mead. Curious though it may seem, it is therefore probable that their non-use of alcohol is due simply to the fact of their having no vessels suitable for brewing it. Such vessels as they have consist of shells, gourds, bottles made from skins or closely plaited rushes, and the like - all unfitted for the retention of large quantities of fermenting liquor. It was not until the introduction of agriculture that man began to make pottery, while the manufacture of glass vessels and wooden barrels is of much later date.
Assuming, then, that man began to brew alcohol about the same time that he began to cultivate the soil, we may estimate the antiquity of alcohol by reference to that of agriculture. Now though we have no means of gauging with precision the date at which agriculture arose, we shall probably not be far wrong in placing it some thirty thousand years back, i.e. about fifteen thousand years before the rise of the Egyptian civilization; and if we suppose that man's evolution from his anthropoid precursor occupied a million years, the discovery of alcohol must, in the light of those unchronicled ages, be regarded as of comparatively recent date. In any case it is clear that man had come well within reach of the highest rung of his long evolution ladder before he learnt to brew intoxicating liquors.
But while possibly acquainted with alcohol for so long a period as three thousand decades, it was not until he had attained a civilized state, say fifteen thousand years ago, that chronic drunkenness was possible for him. For early agricultural man, even though knowing how to make alcohol, had no adequate means of storing and distributing it, and not being able to get a continuous supply, he consequently was unable to indulge in systematic drinking. Such drunkenness as he did, or does (for it is well to remember that the early agricultural stage is still represented among the races of mankind) indulge in, apart from the influence of the white man, was, and is, essentially spasmodic, and connected for the most part with special festivals or ceremonials, for each of which the alcohol must be specially brewed.
It is necessary to insist upon this point because alcohol could not have exerted any marked racial effect on man until he had the opportunity of becoming not merely occasionally, but continuously, drunk.