Above all the intensity of mental stimuli is always relative. The psychologist knows the experiments which determine that we perceive the difference of impressions as alike when the stimuli are proportional. If I have a ten-pound weight in one hand, I may find that I must have one pound more in the other hand to discriminate the difference. Now if I take twenty pounds in the one hand, then it is not sufficient to have one pound more in the other, but I must have twenty-two pounds in the other to feel a difference, and if I take thirty pounds, the other weight must be thirty-three. We feel equal differences when the weights stand in the same relation. The man who owns a hundred dollars will enjoy the gain of five and regret the loss of five just as much as the owner of a hundred thousand dollars would feel the gain or loss of five thousand. This fundamental law of the relativity of psychical impressions controls our whole life. The rush of stimuli which might mean a source of nervous disturbance for the villager whose quiet country life has brought about an adjustment to faint impressions may cause very slight stimulation for the metropolitan accustomed for a lifetime to the rhythm of the surroundings. Yet that quiet countryman may react in his narrow system not less when the modest changes in his surroundings provoke him. The gossip of his neighbor may undermine his nervous system just as much as a political fight or the struggles of the exchange that of the city man. The same holds true for the purely intellectual engagements. The work which the scholar undertakes should not be measured by the effect which the same appeal to concentrated attention would make on the average man of practical life. There, too, an adjustment to the demand has resulted during the whole period of training and professional work. Every effort should be estimated with reference to the standard of the particular case. This relativity of the mental reaction on the demands of life must always be in the foreground of the psychotherapeutic regime. Even the best physicians too often sin against this principle and accuse the life which a man or woman leads as too exhausting and overstraining simply because it would be overstraining and exhausting to others who are not adjusted to that special standard. Simply to withdraw a patient from the one kind of life and to force on him a new kind with new standards may not be a gain at all. A new adjustment begins and smaller differences from the standard may bring about the same strong intensities of reaction as the large differences brought before. Complete rest, for instance, for a hard brain-worker hardly ought to be recommended unless a high degree of exhaustion has come on. If routine prescriptions are to be admitted at all, they should not be complete rest or complete change of life for any length of time but a continuation of the life for which adjustment has been learned with a reasonable reduction of the demands