384 OF FOOD, AND THE DIGESTI VE. PROCESS. 



405. The absolute quantity of Food required for the maintenance of the Human 

 body in health, varies so much with the age, sex, constitution, and habits of the 

 individual, and with the circumstances in which he may be placed, that it would 

 be absurd to attempt to fix any standard which should apply to every particular 

 case. The appetite is the only sure guide for the supply of the wants of each ; 

 but its indications must not be misinterpreted. To eat when we are hungry, is 

 an evidently natural disposition; but to eat as long as we are hungry, may not 

 always be prudent. Since the feeling of hunger does not depend so much upon 

 the state of fulness or emptiness of the stomach, as upon the condition of the 

 general system, it appears evident that the ingestion of food cannot at once pro- 

 duce the effect of dissipating it, though it will do so after a short time ; so that, 

 if we eat with undue rapidity, we may continue swallowing food long after we 

 have taken as much as will really be required for the wants of the system ; and 

 every superfluous particle is not merely useless, but injurious. Hence, besides 

 its other important ends, the process of thorough mastication is important, as 

 prolonging the meal, and giving time to the system to be made acquainted (as 

 it were) that the supply of its wants is in progress ; so that its demand may be 

 abated in due time to prevent the ingestion of more than is required. It is very 

 justly remarked by Dr. Beaumont, that the cessation of this demand, rather than 

 the positive sense of satiety, is the proper guide. " There appears to be a sense 

 of perfect intelligence conveyed to the encephalic centre, which in health in- 

 variably dictates what quantity of aliment (responding to the sense of hunger 

 and its due satisfaction) is naturally required for the purposes of life; and which, 

 if noticed and properly attended to, would prove the most salutary monitor of 

 health, and effectual preventive of disease. It is not the sense of satiety, for 

 this is beyond the point of healthful indulgence, and is Nature's earliest indica- 

 tion of an abuse and overburden of her powers to replenish the system. It 

 occurs immediately previous to this; and may be known by the pleasurable sen- 

 sations of perfect satisfaction, ease, and quiescence of body and mind. It is 

 when the stomach says, enough; and it is distinguished from satiety by the 

 difference of sensations the latter saying too much." Every medical man is 

 well aware how generally this rule is transgressed; some persons making a regu- 

 lar practice of eating to repletion ; and others paying far too little attention to 

 the preliminary operations, and thus ingesting more than is good for them, even 

 though they .may actually leave off with an appetite. 



406. Although no universal law can be laid down for individuals, however, it 

 is a matter of much practical importance to be able to form a correct average 

 estimate. It is from the experience afforded by the usual consumption of food 

 by large bodies of men, that our data are obtained; and these data are sufficient 

 to enable us to predict with tolerable accuracy what will be required by similar 

 aggregations, though they can afford no guide to the consumption of individuals. 

 We shall first consider the quantity sufficient for men in regular active exer- 

 cise; and then inquire how far that may be safely reduced for those who lead a 

 more sedentary life. The Diet-scale of the British Navy may be advantage- 

 ously taken as a specimen of what is required for the first class. It is well 

 known that an extraordinary improvement has taken place in the health of sea- 



And it seems not improbable, too, that this alteration in diet has much to do with that 

 diminished power of sustaining active depletory treatment, which, according to the obser- 

 vations of practitioners of long experience, characterizes the present generation as com- 

 pared with the preceding. But whilst there is a diminished capability of bearing large 

 bloodlettings, violent purgation, &c., there is at the same time such an increased tendency 

 to a favorable termination in many of those diseases for which they were formerly ac- 

 counted necessary, as should remove all regret at this change of constitution. On the 

 question of " Vegetarianism," the Author may refer to his articles on that subject in the 

 Brit, and For. Med.-Chir. Rev.," vol. vi. pp. 76 and 399. 



