Page:Encyclopædia Britannica, Ninth Edition, v. 7.djvu/227

209 DIETETICS 209 Pleasure as an object of Dietetics. The social importance of gratifying the palate has certainly never been denied in practice by any of the human race. Feasting has been adopted from the earliest times as the most natural expression of joy, and the readiest means of creating joy. If ascetics have seemed to put the pleasure away from them, they have done so in the hope of purchasing by their sacrifice something greater and nobler, and have thus tacitly conceded, if not exaggerated, its real value. Experience shows that its indulgence, unregulated by the natural laws which govern our progress in civilization, leads to unutterable degradation and meanness, brutalizes the mind, and deadens its per ception of the repulsiveness of vice and crime. But that is no cause why this powerful motive power, governed by right reason, should not be made subservient to the highest purposes. The times of meals must be regulated with a regard to the disposal of the remainder of the day, whether that depends on choice or on necessity. Violent exertion of either mind or body retards digestion ; and therefore, when this is practised, food is not called for so soon as on a clay of rest. The heaviest meal should be postponed till the day s work is done ; it is then that social home joys give the requisite repose to the body and mind. Light eaters may dine as late as they please, but those of larger appetite should lengthen the interval between their repast and bed-time. After the night s sleep and the long fast which has emptied the digestive canal of its nutritive contents, a breakfast should be taken before any of the real business of life be begun. It is no proof of health or vigour to forego it without incon venience; but it is proof of health and vigour to be able to lay in then a solid foundation for the day s labour. Not less than four and not more than six hours should elapse before the store is again replenished. A light farinaceous lunch with vegetables and fruit may be made most appetizing, and is followed by a cheerful afternoon, whereas a ponderous meat and wine meal entails heaviness of spirit. Diet in relation to Economy. Due Proportion of Animal and Vegetable Food. It has been taken for granted thus far, that the mixed fare, which has met the approval of so many generations of men, is that which is most in accordance with reason. But there are physiologists who argue that our teeth resemble those of the vegetable-feeding apes more than those of any other class of animal, nnd that therefore our most appropriate food must be of the fruits of the earth. 1 And if we were devoid of the intelligence which enables us to fit food for digestion by cookery, it is probable no diet would suit us belter. But our reason must not be left out of account, and it is surely quite as natural for a man to cook and eat every thing that contains in a convenient form starch, fat, albumen, fibre, and phosphorus, as it is for a monkey to eat nuts or an ox grass. The human race is naturally omnivorous. Moreover, man is able not only to develop his highest faculties and perform all his duties on any form of digestible aliment, but he is able also very much to diminish the requisite quantities by a due admixture. The diet which supplies the demand most accurately will be the most economical in the highest sense. And that this diet is a mixed one can be shown by the following method of calculation. We can measure by experiment the ultimate elements of all that is thrown off from the body as the result of vital decomposition, the ashes, the smoke, and the 1 Milne- Ed wards, Cours de Physiologic, vol. vi. p. 198. gases which the fire of life produces ; and thus we can lay down a rule for the minimum quantity of those elements which the daily food must contain to keep up the standard weight. If the diet be such as to make it necessary to eat too much of one element in order to secure a sufficient amount of another, there is a waste, and the digestive viscera are burdened with a useless load. But there is no single article procurable for the food of the adult population which presents the exact proportion of elements required by an adult, and therefore no single article alone can sup ply human wants without waste. As an example, apply this reckoning to the elements carbon and nitrogen, which constitute the main bulk of the solids in our food and in our bodies. Suppose a gang of 100 healthy prisoners to excrete, in the shape of breathed air and evacuations, 71 J ft&amp;gt; of carbon and 4 ft&amp;gt; of nitrogen (which is pretty nearly the actual amount of those elements in the dried solids of the secreta, as estimated by current physiological works). Both nitrogen and carbon to that extent must of course be supplied in the food. Now, if you fed them on bread only, there would be wanted daily at least 380 ft&amp;gt; of it to sustain them alive long, for it takes that weight to yield the 4^ 8&amp;gt; of nitrogen daily excreted ; while, in the 380 ft) of bread there are 128J ft) of carbon, which is 57 Ib above the needful quantity of that substance. 2 If, on the other hand, the bread were replaced by a purely animal diet, there would have to be found 354 ft) of lean meat in order to give the 1 ft of carbon ; and thus there would be wasted 105 Ib of nitrogen contained in the meat, over and above the 4| ft) really required to prevent emaciation. 3 In the first case each man would be eating about 4 ft) of bread, in the second 3 ft) of meat per diem. If he ate less, he would lose his strength. The first would carry about with him a quantity of starch, and the last a quantity or albuminous matter not wanted for nutrition, and would burden the system with an useless mass very liable to decompose and become noxious. When work is undertaken, much more is actually wanted. According to Mr Vizetelly, the labourer in a Spanish vine yard consumes daily between 8 and 9 ft) of vegetable food, consisting of bread, onion-porridge, and grapes. 4 And when animal food alone is taken, as in the case of the Esquimaux, 20 ft) of it a day is the usual allowance. Now, if a mixed dietary be adopted for the gang of 100 prisoners before mentioned, 200 Ib of farinaceous food, with 56 Ib of animal muscle, would fulfil the requirements of the case ; 2 ft) of bread and a little more than | ft) of meat a head would be enough, under ordinary circumstances, for each man s daily food. 200 Ibs. of bread contains 60 of carbon, 2 of nitrogen. 60 Ibs. of meat (including 12,| Ibs. of f:it on it), contains 12 ,, 2J ,, 72 4J Balance of Food and Work. The most important modifi cation to be made in the above estimate arises from the differences of work demanded. Men may exist in inaction on a scale of food supply which is followed by death from starvation when they are put to hard labour. It is of im portance, therefore, to have some measure of the effects of physical exertion. And here mechanical science has con- 2 Dr Letheby s analysis gives 8 1 percent, of nitrogenous matter to bread (Lectures on Food, p. C). Of this jth is nitrogen, Boussingault s analysis of gluten giving 14 60 per cent. (Annales de Chim. et Phys., Ixiii. 229). M. Payen makes the proportion of nitrogen to carbon in bread as 1 to 30. 3 The proportion of nitrogen to carbon in albumen is as 1 to 3 (15 5 to 53 5 by Mulder s analysis, quoted in Lehmann, Phys. Chemie, i. 343). In red meat there is 74 per cent, of water (ditto iii. 96). 4 Facts about Shemj, chap. i. 1876 ; and Sir John Boss s Second I Voyage for the Discovery of the North-West Passage, p. 413. VII. 27