Self indulgent, luxurious habits, are highly injurious to healthy digestion; but on this threadbare subject it would be mere waste of time to enlarge. Idleness, and the want of a definite pursuit in life, must also rank high in this class of causes. To preserve the general health, occupation is as necessary for the active mind as exercise is for the vigorous body.
The importance in the system of the reproductive functions is such that their exhaustion must, sooner or later, react on the functions of nutrition. Lamentable instances of the results of sexual excess are occasionally met, and dyspepsia is almost invariably one of these. But the injurious effects of a free indulgence of the sexual instincts have been highly colored. Unprincipled men, who prey on the young and the inexperienced, magnify and distort the significance of certain ailments, the treatment of which, in too many instances, passes out of the hands of the regular practitioner.
In youth, the sensations are quickest, and the impressions most fresh and vivid; so that it might be supposed life would be always then most keenly enjoyed. But its earlier years are frequently clouded. An aching desire for change and excitement often destroys present happiness; and, when the desired excitement is unattainable, ennui and a hopeless indolence ensue. Experience convinces me that this condition of mind is but a frequent result of a feeble state of health. This can be often traced to an overstrain of the mental powers—a strain daily increased among men by a spirit of emulation, fostered and rewarded by the competitive system to an extent formerly unknown. Accomplishments also among girls are made objects of relentless perseverance. In both sexes, at a time when growth is incomplete, and new functions are springing into existence, the mental are developed at the expense of the bodily powers. Nutrition suffers because appetite and digestion are impaired, and the power of the mind itself is weakened. Over-exertion of mind fatigues equally with that of the body. No reasonable doubt can therefore be entertained that thinking is the result of a physical action in the brain. In what may be for convenience termed secretion of thought, demands are made on nutrition just as in bodily exercise. It has been often observed that great thinkers, if healthy, are usually large eaters.
The state of the air we breathe is highly important in relation to dyspepsia. We live at the bottom of an elastic medium, presenting everywhere the same general composition, and exactly adapted to the exigencies of animal life. Any accidental impurity of the atmosphere tends to disturb the balance of health. Oxygenation of blood is the object of respiration; and its replenishment is the object of digestion. On the other hand, the digestive secretions, as well as the nervous energy by which they are governed, depend for their perfection upon the perfect state of the blood. For this reason ill-ventilated workshops and crowded sleeping-rooms among the poor, and the overheated and
