As a general rule, then, not more than five hours ought to intervene betwixt breakfast and dinner. If the mode of life be such as involves great activity in the open air, or the period of life be one of rapid growth or filling up (as during youth or convalescence from illness), the interval may with propriety be shortened; whereas, if the mode of life be sedentary, and unattended with much activity of nutrition, the interval may be considerably protracted without much inconvenience. Much, also, ought to depend on the natural rapidity or slowness of digestion. In some constitutions, chylification goes on so slowly that the individual can pass with ease eight or ten hours without food; whereas, in others, it is so rapid that a fresh supply becomes necessary in half the time. Spallanzani himself was an example of the former kind; for in him digestion went on so slowly that he was unable for study till five or six hours after even a very spare dinner. The proper rule in every case is, to take dinner at such an interval after breakfast as the return of healthy appetite indicates, whether that interval be longer or shorter than the average specified. That, according to this rule, the _general_ time for dinner ought to be somewhere about five hours after an ordinary breakfast, is evident from the almost universal return of appetite at the end of such an interval, and from the fact that many, through sheer inability to resist longer the wholesome cravings of nature, are in the regular practice of eating dinner at that time, but to save appearances give it the name of _luncheon_; by which means they hold themselves entitled to the enjoyment of a second and more substantial dinner later in the day. Invalids, dyspeptics, and all who, possessing vigorous digestion, wish to retain it, will do well to follow the intentions of Nature, and observe the intervals which she has appointed. Those who disregard them, and still digest without difficulty, have reason to be grateful to Providence; but they may rest assured that they will longer enjoy their privilege, and better evince their gratitude, by submitting their conduct to the ordinary laws of the animal economy, than by presuming too much on their supposed exemption from the salutary restraints of reason and experience. Supposing nine o’clock to be the hour of breakfast, the natural dinner-hour would thus be two o’clock; and such, accordingly, is that sanctioned by the most extended experience, and which ought to be adhered to by all whose occupations will admit of its observance, and who wish to enjoy the highest health of which they are susceptible.