Similarly Rüdin found the effects of a single dose of alcohol to persist, as regards some forms of mental disturbance, for twelve hours, for other forms twenty-four hours, and for yet others thirty-six hours and more. But Rüdin's experiments bring out another aspect of the subject, which no one who considers the alcohol question in any of its phases should overlook: the fact, namely, that individuals differ greatly in their response to a given quantity of the drug. Thus, of four healthy young students who formed the subjects of Rüdin's experiment, two showed very marked disturbance of the mental functions for more than forty-eight hours, whereas the third was influenced for a shorter time, and the fourth was scarcely affected at all. The student who was least affected was not, as might be supposed, one who had been accustomed to take alcoholics habitually, but, on the contrary, one who for six years had been a total abstainer. Noting thus that the effects of a single dose of alcohol may persist for two or three days, one is led to inquire what the result will be if the dose is repeated day after day. Will there then be a cumulative effect, or will the system become tolerant of the drug and hence unresponsive? Some experiments of Smith, and others of Kürz and Kraepelin have been directed toward the solution of this all-important question. The results of the experiments show a piling up of the disturbing effects of the alcohol. Kürz and Kraepelin estimate that after giving eighty grams per day to an individual for twelve successive days, the working capacity of that individual's mind was lessened by from twenty-five to forty per cent. Smith found an impairment of the power to add, after twelve days, amounting to forty per cent.; the power to memorize was reduced by about seventy per cent. Forty to eighty grams of alcohol, the amounts used in producing these astounding results, is no more than the quantity contained in one to two litres of beer or in a half-bottle to a bottle of ordinary wine. Professor Aschaffenburg, commenting on these experiments, points the obvious moral that the so-called moderate drinker, who consumes his bottle of wine as a matter of course each day with his dinner--and who doubtless would declare that he is never under the influence of liquor--is in reality never actually sober from one week's end to another. Neither in bodily nor in mental activity is he ever up to what should be his normal level.