The action of alcohol on the nervous tissues constitutes, in the eyes of the majority, the main injury that alcohol does to a human being. Certain it is that the action of alcohol on the brain does more to distort and pervert a man's relationship with his environment than any other action which alcohol has on the body. It is through the poison of this organ that the personality of the individual is so changed and so poisoned that a degeneration of the individual in character and morals is brought about. It is here, too, that the widest differences of tolerance and intolerance to alcohol are shown. Some men may consume enormous quantities and their mental balance apparently remain intact. Other individuals cannot take a single glass of wine without being distinctly affected by it, or rendered unmistakably drunken. The gross injuries found in the brain of those dying from the effects of alcohol are partly due to the effect of alcohol on the circulation and the injury to the blood vessels, thus diminishing the nutrition of the brain and injuring the brain tissue itself, and besides, as we have seen in other viscera, to the increase in connective tissue.
It is not necessary here to go into the details of the minute formation of the cells, how each cell is formed of a cell body and many branches, as one may conceive, growing like a tree or bush with the many branches stretching out and touching other branches of related and adjacent cells. When these dendrites or branches are in contact, there is an interrelationship between the processes of the two cells. Alcohol causes a retraction of the tiny branches one from another and the cells are dissociated, so that the mental processes become dissociated from each other, and the cells themselves degenerate and are unable to carry on their functions; thus we see the functions of memory and of the reproduction of images by memory prevented, the inability of the mind to reason, through the inability of the mind to call up former experiences, feelings and ideas, and a weakening of the power of each cell to take in impressions.
Every person who drinks alcohol to excess will not show every form of mental deterioration that may be produced by excessive indulgence, and the degree of deterioration in intelligence which goes to make up the sum total of mentality varies greatly in different individuals. All who drink alcohol to excess, however, show some diminution in their judgment. Judgment means the power of recalling various memories of perceptions through the senses, which have come in from the outside world, memories of ideas, memories of emotions, and all the complicated association of ideas that these bring up, and in the recalling of them weigh each one with the other and judge of the value between them. This also means reasoning and decision for action. This power of reasoning and judging is weakened in the alcoholic, and in any brain long poisoned by alcohol it is an impossibility to exercise it. Memory itself is also weakened. There is excessive forgetfulness of the recent past, and in some cases of advanced alcoholism there is absolute forgetfulness of wide gaps of years; a man may be unable to remember anything from the last five minutes back for twenty years, and then remember back to childhood. The memories of childhood are more easily stamped on the brain than are those of adult life, both because it takes less to impress a child, and because there is not the complexity of ideas crowding into the brain, nor the complexity of association of ideas to be recorded. Therefore memories of childhood make a deeper impress and last longer, and so the complex memories of the adult are the first to be forgotten in the alcoholic, and those of childhood remain.
