The effects of mental strain are often mingled with, and aggravated by, those of stimulants which have been used to spur the flagging energies. Alcohol, tobacco, opium, or coffee used in this way finally increase the very discomforts which at first they relieved. II. Personal Hygiene in its Relations to the Practice of Medicine. In the preceding section have been indicated briefly some of the principal causes of disease and the methods for their investigation or removal. We have now to consider some of the practical applications which may be made of the laws of etiology and prevention of disease in the treatment of the sick. While the removal of the cause of illness by no means always effects a cure, yet the importance of a knowledge of this cause as an aid to diagnosis, prognosis, and therapeutics is so evident as to require no proof. To discuss with anything like completeness the practical applications of what would be commonly considered as hygienic rules in the treatment of disease would be to write a treatise on nursing, and would also include a large part of the practice of medicine, for regimen is the more important half of practical therapeutics. The hygienic requirements peculiar to each disease will be pointed out by the writers upon special subjects, and I shall only venture upon one or two general remarks in addition to the hints already given in speaking of the several causes. In the acute stages of disease the sensations--or, if the term be preferred, the instincts--of the patient are usually the best guide to his regimen so far as they go. In most cases he desires quiet, shade, but not absolute darkness, and little or no food, although there is often a craving for drinks, especially of a cooling character. In the specific fevers which have a tolerably definite period and course it is important to keep up the nourishment even during the period of anorexia, in order to provide against the debility which is to follow. This nourishment is best given in the form of drink, and very frequently fresh milk is the type of what is required. The old notion that whatever a sick man desired must be hurtful, and therefore that the fever patient must be kept hot and refused cool water, has now almost entirely passed away.