A short outline may here be given of some of the researches undertaken during recent years on the mental effects of alcohol, taken for the most part in small or moderate doses. It will serve to exemplify the methods adopted and to indicate the general results obtained.

Kraepelin of Munich has carried out a long series of careful investigations respecting the influence of alcohol, taken in moderate or small doses, upon the mental functions. The amount of the dose varied, but as a rule was about an ounce, diluted with water. Sometimes one-half, or one-quarter, of this quantity was used. In fact, the amounts were often far below those frequently taken at meals by ordinary individuals. Such mental processes as reading aloud, adding columns of figures, calculating arithmetically, memorising words or numbers, and associating ideas with words, were employed in the tests. In certain of the experiments the rate of mental action was measured by means of time-recording apparatus designed to indicate accurately the reaction-period - i.e., the time occupied in making a response to a given signal. In other experiments, the ability to add figures correctly was tested upon subjects sometimes taking alcohol, sometimes refraining from it. The outlines of one such experiment may be given as a simple example: -

First six days, no alcohol taken. Practice in adding figures for half an hour daily. The ability to add increased every day.

Next twelve days, alcohol taken. In spite of the influence of the previous days' practice, the capability of adding did not increase. On the contrary, it began to decrease very rapidly.

1 " Alcohol, its Action on the Human Organism," p. 37.

Nineteenth day, alcohol stopped. Immediate improvement shown.

Twenty-sixth day, alcohol resumed. A decided decrease in the power of adding figures was again shown.

The general results arrived at from all the experiments were that in the simpler, more or less automatic work, mental activity was slightly quickened at the outset under the influence of alcohol, but in most cases began to slow down after a few minutes, the diminution becoming more and more marked, and enduring as long as the alcohol was in active operation in the body, namely, four to five hours. When, on the other hand, the higher powers of the mind, e.g., those involving association of ideas and the formation of judgments, were called into play, there was no real quickening of the brain activity under alcohol. The slowing effect began from the first, and continued throughout. Moreover, not only does alcohol, according to this observer, delay the rapidity of cerebral association. It alters the quality also, favouring the inferior kinds of mental association and weakening the higher associations. In other words, even small doses of alcohol influence adversely, from the very first, the finer work of the brain-cells.

Aschaffenburg made a careful series of observations upon the work of compositors, done when alcohol was taken in "dietetic ' quantity, and also without alcohol. He found that there was a distinct impairment of mental activity, amounting to about 9 per cent. as measured by the output of work, when alcohol was taken. The impairment was absent in one case only out of eight.

Other investigators have studied the duration of the effect produced by alcohol. Furer used amounts such as are contained in two litres of strong beer or half a litre of wine. The effects were found to last all the following day, causing a dulling of mental labour, although the subject was under the impression that his work was just as good as usual. Kurz, taking 80 grams of alcohol in water on twelve successive evenings, found that there was a decided diminution in the day's work (calculating and studying) as compared with that done on alcohol-free days, and that this effect persisted until the fifth day after ceasing to take alcohol. A single large dose acts for twenty-four or even forty-eight hours.

W. McDougall, describing a 'method for the study of concurrent mental operations and mental fatigue,"1 investigated the effect of dietetic quantities of alcohol upon subjects performing a certain task - namely, accurately marking dots driven past an opening at a known rate. In one series of experiments he found that the errors under the influence of alcohol compared with the normal errors were as 583 to 379. In another (shorter) series they were as 351 to 298. Three ounces of whisky caused 53 per cent. more errors than when the brain was under normal conditions. On the other hand, the errors when tea was taken were less than the normal.

1 British Journal of Psychology, 1.

The general results of these and other experiments go to show that, as regards the effects of small or moderate doses of alcohol upon the nervous and neuro-muscular system: -

(1)

Alcohol lengthens the time taken to perform complex mental processes, although the person experimented upon imagines that his psychical activities are rendered more rapid.

(2)

There is an initial stage of temporary stimulation or exhilaration, chiefly due to a slight numbing of the higher nerve-centres; but this is followed by a prolonged depressant after-stage.