The securing of personal information is of the utmost importance in determining the affections that psychotherapy will relieve, because very often details of life and habits are discovered that can be so modified by instruction as to bring about a disappearance of unfavorable physical influences. It is indeed surprising to find how many unreasonable things people do from habit, from unfortunate persuasion, or from lack of knowledge. In many of the minor chronic ailments that are the source of so much mental discomfort to patients, the physician finds that a change in the patients' habits, not necessarily of marked degree, may make all the difference between cheerful health and rather despondent low-spirited feeling. Now that epidemic disease has become rarer, a physician's practice, especially among the better classes, is much more taken up with these minor ailments than with the typical classical diseases. The ordinary history of their ailments, as patients commonly present them, especially when there are neurotic elements, is likely to be meager in what is objective, but consists mostly of the subjective. Such patients have much to say of their sensations, their feelings, their dreads, their surmises, their conclusions as to their particular condition, and especially the hereditary elements in it, but comparatively little of the objective realities of their ills and of their environment. What the physician needs to know about them is their habits of life, their daily routine of existence, just as minutely as it is possible to obtain the information. There is just one way to get the latter details, and that is to inquire particularly with regard to actual happenings. In chronic conditions of many kinds, it is so helpful that it will always be worth the physician's while to get at these details, especially in supposedly puzzling cases for which various forms of treatment have been already tried. In spite of every precaution in this matter, the physician sometimes finds, after a series of consultations, that some point which when brought to light he considers to be of great importance, has been thought so trivial by the patient that it was never mentioned, in spite of the most careful questioning. In all medical practice the rule is that mistakes of diagnosis are much more due to neglect in eliciting necessary information than either to lack of expertness in diagnosis, or lack of knowledge of the significance of symptoms.