So true is it that the Creator has established a relation between action and nutrition, that when we attempt for any length of time to combine a full and nutritious diet with systematic inactivity, the derangement of health which generally ensues gives ample proof of the futility of struggling against His laws. Individuals, indeed, may be met with, who, from some peculiarity of constitution, suffer less than the generality of mankind from making the experiment; but even those among them who escape best, generally owe their safety to the constant use of medicine, or to a natural excess in some of the excretory functions, such as perspiration or the urinary or alvine discharges, by means of which the system is relieved much in the same way as by active exercise; and hence the remark made by Hippocrates, that severe perspirations arising during sleep without any other apparent cause are a sure sign that too much nourishment is made use of. In others, again, the day of reckoning is merely delayed, and there is habitually present a state of repletion, which clogs the bodily functions, and may lead to sudden death by some acute disease when the individual is apparently in the highest health. I am acquainted with several individuals of this description, who, in the absence of all bodily exercise, are accustomed to live very fully,--to eat in the morning a hearty breakfast, with eggs, fish, or flesh,--a good solid luncheon, with wine or malt liquor, in the forenoon,--a most substantial dinner, with dessert and several glasses of wine, and afterwards tea and wine and water, in the evening,--and who nevertheless enjoy tolerably good digestion. But this advantage is generally only temporary, and even when permanent can scarcely be considered as a boon; because it is gained at the direct expense either of a very full habit of body and an unusual liability to abdominal congestion and all its attendant evils, or of frequent and profuse perspirations, and severe attacks of bowel complaint, endangering life; so that strictly considered such cases are no exceptions to the general rule. It is, then, no idle whim of the physician to insist on active exercise as the best promoter of appetite and digestion. Exercise is, in fact, the condition without which exhalation and excretion cannot go on sufficiently fast to clear the system of materials previously taken in; and where no waste is incurred, no need of a fresh supply, and consequently, in a healthy state of the system, no natural appetite, can exist. It is therefore not less unreasonable than vain for any one to insist on possessing, at the same time, the incompatible enjoyments of luxurious indolence and a vigorous appetite,--sound digestion of a hearty meal, and general health of body; and no one who is aware of the relation subsisting between waste and appetite can fail to perceive the fact, and to wonder at the contrary notion having ever been entertained. * * * * *