Chapter 2

There is reciprocity between the teeth and digestive organs of animals and their natural food. The grasses, leaves, &c., which are consumed by the herbivora, contain a large proportion of cellulose and woody tissue. Consequently, the food is bulky; it is but slowly disintegrated and the nutritious matter liberated and digested. The cellulose appears but slightly acted upon by the digestive juices. The herbivora possess capacious stomachs and the intestines are very long. The carnivora have simpler digestive organs and short intestines. Even they consume substances which leave much indigestible residue, such as skin, ligaments and bones, but civilised man, when living on a flesh dietary removes as much of such things as possible. The monkeys, apes, and man (comprised in the order _Primates_) have a digestive canal intermediate in complexity and in length to the herbivora and carnivora. A certain quantity of indigestible matter is necessary for exciting peristaltic action of the bowels. The carnivora with their short intestinal canal need the least, the frugivora more, and the herbivora a much larger quantity. The consumption by man of what is commonly called concentrated food is the cause of the constipation to which flesh-eating nations are subject. Most of the pills and other nostrums which are used in enormous quantities contain aloes or other drugs which stimulate the action of the intestines.

Highly manufactured foods, from which as much as possible of the non-nutritious matter has been removed is often advocated, generally by those interested in its sale. Such food would be advantageous only if it were possible to remove or modify a great part of our digestive canal (we are omitting from consideration certain diseased conditions, when such foods may be useful). The eminent physiologist and bacteriologist, Elie Metchnikoff, has given it as his opinion that much of man's digestive organs is not only useless but often productive of derangement and disease. In several cases where it has been necessary, in consequence of serious disease, to remove the entire stomach or a large part of the intestines, the digestive functions have been perfectly performed. It is not that our organs are at fault, but our habits of life differ from that of our progenitors. In past times, when a simple dietary in which flesh food formed little or no part, and to-day, in those countries where one wholly or nearly all derived from vegetable sources and simply prepared is the rule, diseases of the digestive organs are rare. The Englishman going to a tropical country and partaking largely of flesh and alcohol, suffers from disease of the liver and other organs, to which the natives and the few of his own countrymen, living in accordance with natural laws are strangers.

Indigestible Matter--Food is never entirely digested. As a reason against confining ourselves solely to vegetable food, it has been stated that such is less perfectly digested than animal food and that it therefore throws more work on the digestive organs. It is also urged that on this account a greater quantity of vegetable food is required. We have shown elsewhere that, on the contrary, vegetarians are satisfied with a smaller amount of food. Man requires a small quantity of woody fibre or cellulose in his food to stimulate intestinal action and prevent constipation.

It is difficult to determine how much of a food is unassimilated in the body. This is for the reason of the intestinal refuse consisting not only of undigested food, but also of residues of the digestive juices, mucus and epithelial debris. These latter have been shown to amount to from one-third to one-half of the whole of the fæces, which is much more than had previously been supposed.

John Goodfellow has shown that of very coarse wholemeal bread quite 14 per cent. was undigested, whilst bread made from ordinary grade wholemeal showed 12.5 per cent. Such a method of analysis was adopted as it was believed would exclude other than the food waste. The experiments were made on a person who was eating nothing but the bread. It seems probable that a smaller proportion would have remained unassimilated had the bread not formed the sole food. It is advisable that wheatmeal he ground as finely as possible, the coarse is not only to a less extent assimilated but apt to irritate the bowels. Notwithstanding that fine white bread gave only 4.2 per cent. and a coarse white bread 4.9 per cent. of waste, a fine wheatmeal bread is more economical as the same quantity of wheat produces a greater weight of flour richer in proteid and mineral matter. From a large number of experiments with man, it has been calculated that of proteids there is digested when animal food is eaten 98 per cent., from cereals and sugars 8 per cent., from vegetables and fruits 80 per cent. The difference between the proportions digested of the other food constituents was much less. Although there is here a theoretical advantage in favour of animal food, there are other considerations of far more importance than a little undigestible waste. The main question is one of health. In some dietary experiments of a girl aged 7, living upon a fruit diet, of whom we have given some particulars elsewhere, Professor Jaffa gives the following particulars. During the ten days trial the percentages absorbed were proteids 82.5, fat 86.9, nitrogen free extract 96, crude fibre 80, ash 5.7, heat of combustion in calories 86.7. He says, "generally speaking, the food was quite thoroughly assimilated, the coefficients of digestibility being about the same as are found in an ordinary mixed diet. It is interesting to note that 80 per cent. of the crude fibre appeared to be digested. The results of a number of foreign experiments on the digestibility of crude fibre by man are from 30 to 91.4 per cent., the former value being from mixed wheat and rye, and the latter in a diet made of rice, vegetables and meat."

TABLE OF ANALYSIS OF FOOD

Key: P = Proteins. Cb = Carbohydrates. C = Cellulose. R = Refuse. W = Water. Ca = Calories.

Nt'nt P. Fat. Cb. Ash. C R W Ca Ratio Wholemeal, G. 14.9 1.6 66.2 1.7 1.6 ... 14.0 1577 4.68 Fine Flour, G. 9.3 0.8 76.5 0.7 0.7 ... 12.0 1629 8.4 Medium Flour, G. 12.1 0.9 72.2 0.9 0.9 ... 13.0 1606 6.13 Bread, Wholemeal, G. 12.2 1.2 43.5 1.3 1.8 ... 40.0 1086 3.8 Bread, White, G. 7.5 0.8 53.8 0.9 ... ... 37.0 1174 7.4 Macaroni, U. 13.4 0.9 74.1 1.3 ... ... 10.3 1665 5.67 Oatmeal, D. 14.8 9.6 63.3 2.2 1.4 ... 8.7 1858 5.72 Maize, American, S. 10.0 4.25 71.75 1.5 1.75 ... 10.75 1700 8.12 Rice, husked, U. 8.0 0.3 79.0 0.4 ... ... 12.3 1630 10.0 Rye Flour, U. 6.8 0.9 78.3 0.7 0.4 ... 12.9 1620 11.8 Barley, Pearl, C. 6.2 1.3 76.0 1.1 0.8 ... 14.6 1584 12.7 Buckwheat Flour, U. 6.4 1.2 77.9 0.9 ... ... 13.6 1619 12.6 Soy Bean, C. 35.3 18.9 26.0 4.6 4.2 ... 11.0 1938 1.93 Pea-nut, C. 24.5 50.0 11.7 1.8 4.5 ... 7.5 2783 5.2 Lentils, U. 25.7 1.0 59.2 5.7 ... ... 8.4 1621 2.4 Peas, dried, U. 24.6 1.0 62.0 2.9 4.5 ... 9.5 1655 2.6 Peas, green, E.U. 7.0 0.5 15.2 1.0 1.7 ... 74.6 465 2.3 Haricots, C. 23.0 2.3 52.3 2.9 5.5 ... 14.0 1463 2.5 Walnuts, fresh k., C. 12.5 31.6 8.9 1.7 0.8 ... 44.5 1563 6.33 Walnut kernels 21.4 54.1 15.2 2.9 1.4 ... 5.0 2964 6.33 Filberts, fresh ker., C. 8.4 28.5 11.1 1.5 2.5 ... 48.0 1506 8.9 Tomatoes, U. 1.2 0.2 3.5 0.6 0.5 ... 94.0 105 3.3 Grapes, U. 1.0 1.2 10.1 0.4 4.3 25 58.0 335 12.8 Apples, E.U. 0.4 0.5 13.0 0.3 1.2 (25) 84.6 290 35.3 Raisins, E U. 2.6 3.3 76.1 3.4 ... (10) 14.6 1605 32.0 Dates, E.U. 2.1 2.8 78.4 1.3 ... (10) 15.4 1615 40.0 Banana, C.D. 1.71 ... 20.13 0.71 1.74 ... 75.7 406 11.7 Banana Flour, P. 3.13 1.73 82.4 5.93 1.21 ... 5.6 1664 27.5 Potatoes, K. 1.9 0.2 20.7 1.0 0.7 ... 75.7 429 11.0 Turnips, E. 1.3 0.2 6.8 0.8 1.3 (30) 89.6 159 5.57 Onions, E.U. 1.6 0.3 9.1 0.6 0.8 (10) 87.6 225 6.1 Cabbage, E U. 1.6 0.3 4.5 1.0 1.1 (15) 91.5 123 3.23 Asparagus, U. 1.5 0.1 2.3 1.2 0.5 ... 94.4 85 1.7 Celery, E.U. 1.1 0.1 3.3 1.0 ... (20) 94.5 85 3.2 Mushrooms, U. 3.5 0.4 6.8 1.2 ... ... 88.1 210 2.2 Tapioca, U. 0.4 0.1 88.0 0.1 ... ... 11.4 1650 220 Sugar ... ... 100 ... ... ... ... 1860 ... Oil ... 100 ... ... ... ... ... 4220 ... Milk 3.6 3.7 4.6 0.73 ... ... 87.4 309 3.56 Butter, fresh 0.8 83.5 1.5 0.2 ... ... 14.0 3566 234 Cheese, U. 25.9 33.7 2.4 3.8 ... ... 34.2 1950 3.0 Hen's Eggs, U. 11.9 9.3 ... 0.9 ... 11.2 65.5 635 1.74 Beef, loin, U. 16.4 16.9 ... 0.9 ... 13.3 52.9 1020 2.3 Beef, loin, edible p., U. 19.0 19.1 ... 1.0 ... ... 61.3 1155 2.3 Mutton, shoulder, U. 13.7 17.1 ... 0.7 ... 22.1 46.8 975 2.77 Pork, Ham, U. 14.3 29.7 ... 0.8 ... 10.3 45.1 1520 4.6 Bacon, smoked, U. 9.5 59.4 ... 4.5 ... 8.7 18.4 2685 13.9 Fowl, U. 13.7 12.3 ... 0.7 ... 25.9 47.1 775 2.0 Goose, U. 13.4 29.8 ... 0.7 ... 17.6 38.5 1505 4.9 Cod, dressed, U. 11.1 0.2 ... 0.8 ... 29.9 58.5 215 0.04 Mackerel, whole, U. 10.2 4.2 ... 0.7 ... 44.7 40.4 365 9.13 Oysters, L. 8.75 0.92 8.09 2.4 ... ... 79.8 352 1.16

NOTES ON THE TABLE OF ANALYSIS.--Under calories are shown kilo-calories per pound of food. In the analysis marked U the crude fibre or cellulose is included with the carbo-hydrate, the figures being those given in Atwater's table. He has found that from 30 to 91 per cent. of the crude fibre was digested, according to the kind of food. The term fibre or cellulose in analytical tables is not a very definite one. It depends upon the details of the method of analysis. In the analyses other than U, the cellulose is excluded in calculating the calories. Nutrient ratio is the proportion of the sum of the carbo-hydrate and fat, compared with the proteid as 1. The fat has first been multiplied by 2.225 to bring it to the same nutrient value as the carbo-hydrate.

U indicates that the analyses are taken from the United States Department of Agriculture Experimental Station, Bulletin 28, the tests being chiefly made by Dr. W.O. Atwater, or under his direction. They are average analyses of several samples. The refuse consists of such parts as are rejected in preparing the food; the outer leaves, skin, stalk, seeds, &c., of vegetables; the shell of eggs; the bone, &c., of meat. E, indicates that the edible portion only of the food has been analysed, and under refuse, in brackets, is shown the quantity rejected before the analysis was made.

There is considerable variation in the same kind of food, according to the variety of seed and conditions of growth &c., especially is this the case with wheat and flour; whenever it has been possible the average of the analyses of many samples have been given. The method of analysis has not always been uniform, frequently the cellulose is included with the carbo-hydrates, and the proteid sometimes includes a very appreciable quantity of non-proteid nitrogenous matter. This is the case in the analysis of the mushrooms. G.--Analyses are by John Goodfellow; it will be noticed that the wheatmeal bread is not made from the same flour as the whole-meal. D.--B. Dyer, average of 19 fine and coarse oatmeals. S, from U.S. Cons. Reports, 1899. C.--A.H. Church. The walnut kernels are in the dried condition as purchased; originally of the same composition as shewn in the fresh kernels. C.D.--Cavendish or Figi variety of banana, analysis by D.W.M. Doherty, N.S. Wales. P.--A. Petermann, U.S. Cons. Banana flour, _musca paradisiaca_ variety. This is widely used in Central America. The flour is from the unripe fruit, and contains starch 45.7 per cent.; on ripening the starch is converted into sugar. K.--Konig, mean of 90 analysis. Milk:--Average of many thousand analyses of the pure. Butter.--Made without salt. L, from the "Lancet," 1903, I, p. 72. Oysters at 2/6 per dozen. The 8.09 per cent. includes 0.91 glycogen (animal starch). The shell was of course excluded, also the liquid in the shell. Apples.--The refuse includes seeds, skin, &c., and such edible portion as is wasted in cutting them away; the analysis was made on the rest.

Cookery.--Flesh is easier to digest raw. A few, on the advice of their doctors, eat minced raw flesh, raw beef juice and even fresh warm blood. Such practice is abhorrent to every person of refinement. Cooking lessens the offensive appearance and qualities of flesh and changes the flavour; thorough cooking also destroys any parasites that may be present. Raw flesh is more stimulating to the animal passions, and excites ferocity in both man and animals. If the old argument was valid, that as flesh is much nearer in composition and quality to our own flesh and tissues, it is therefore our best food, we do wrong in coagulating the albuminoids, hardening the muscle substance and scorching it by cooking.

Fruits when ripe and in good condition are best eaten raw; cooking spoils the flavour. Food requiring mastication and encouraging insalivation is the best. Food is frequently made too sloppy or liquid, and is eaten too hot, thus favouring indigestion and decay of the teeth. The cereals and pulses can only with difficulty be eaten raw. When cooked in water the starch granules swell and break up, the plant cells are ruptured, the fibres are separated and the nutritious matter rendered easy of digestion. The flavour is greatly improved. Cooking increases our range and variety of food. The civilised races use it to excess and over-season their dishes, favouring over-eating.

If baking powders are used they should only be of the best makes. They should be composed of sodium bicarbonate and tartaric acid, in such correct proportions that upon the addition of water only sodium tartrate and carbon dioxide (carbonic acid) should result. Some powders contain an excess of sodium bicarbonate. Self-raising flours should be avoided. They are commonly composed of--in addition to sodium bicarbonate--acid calcium phosphate, calcium superphosphate and calcium sulphate. Common baking powders often consist of the same ingredients, and sometimes also of magnesia and alum. These are often made and sold by ignorant men, whose sole object is to make money. Calcium superphosphate and acid calcium phosphate very frequently contain arsenic, and as the cheap commercial qualities are often used there is danger in this direction. A good formula for baking powder is, tartaric acid 8 ozs., sodium bicarbonate 9 ozs., rice flour 10 to 20 ozs. The last is added to baking powders to improve the keeping quality and to add bulk. The ingredients must be first carefully dried, the sodium bicarbonate at not too high a temperature or it decomposes, and then thoroughly mixed; this must be preserved in well closed and dry bottles. Another formula, which is slow rising and well adapted for pastry, is sodium bicarbonate 4 ozs., cream of tartar 9 ozs., rice flour about 14 ozs. Custard powders consist of starch, colouring and flavouring. Egg powders are similar to baking powders but contain yellow colouring. Little objection can be taken to them if they are coloured with saffron; turmeric would do if it were not that it gives a slightly unpleasant taste. Artificial colouring matters or coal tar derivatives are much used, several of these are distinctly poisonous.

Drinks.--It is better not to drink during eating, or insalivation may be interfered with; a drink is better taken at the end of a meal. The practice of washing down food with hot tea is bad. The refreshing nature of a cup of hot tea, coffee, or cocoa is to a very great extent due to the warmth of the water. The benefit is felt at once, before the alkaloid can enter the blood stream and stimulate the nerve centres. Hot water, not too hot to cause congestion of the mucous membrane, is one of the best drinks. When the purity of the water supply is doubtful, there is advantage in first bringing it to the boil, as pathogenic bacteria are destroyed. Some find it beneficial to drink a cup of hot water the first thing in the morning; this cleanses the stomach from any accumulation of mucus.

If fruit, succulent vegetables, or cooked food, containing much water be freely used, and there be little perspiration, it is possible to do without drinking; but there is danger of taking insufficient water to hold freely in solution the waste products excreted by the body.

Aerated drinks, except a very few of the best, and non-alcoholic beers and wines, are generally unwholesome, from their containing preservatives, foaming powders, artificial flavourings, &c.

Stimulants.--Tea and coffee contain an alkaloid theine, besides volatile oils, tannin, &c. Cocoa contains the milder alkaloid, theobromine. They stimulate the heart and nervous systems; tea and coffee have also a diuretic effect. Formerly they were erroneously thought to lessen tissue waste. These alkaloids, being purins, are open to the general objections named elsewhere. Stimulants do not impart energy or force of any kind, but only call forth reserve strength by exciting the heart, nervous system, &c., to increased activity. This is followed by a depression which is as great, generally greater, than the previous stimulation. Except, perhaps, as an occasional medicine, stimulants, should be avoided. Analysis of cocoa shows a good proportion of proteids and a very large quantity of fat. The claim that it is a valuable and nutritious food would only be true if it could be eaten in such quantities as are other foods (bread, fruits, &c.). Were this attempted, poisoning would result from the large quantity of alkaloid. The food value of half a spoonful or thereabouts of cocoa is insignificant. Certain much advertised cocoa mixtures are ridiculous in their pretentions, unscientific in preparation, and often injurious.

Cereals.--The most valuable is wheat, from its proteid being chiefly in the form known as gluten. From its tenacity, gluten enables a much better loaf to be produced from wheat than from any other cereal. The outer part of the grain is the richest in mineral matter and proteid. Wheatmeal bread shows a considerably higher proteid value than white. A large proportion of the proteid in the outer coats of the wheat berry is, however, not digested, and in some experiments the waste has been enough to quite nullify its seeming advantage over white bread. Coarsely ground, sharp branny particles in bread irritate the intestines, and cause excessive waste of nutriment; but finely ground wheatmeal is free from this objection, and is beneficial in preventing constipation. The comparative value of white and brown bread has been much discussed; it depends both on the quality of the bread and the condition of the digestive organs. Experiments on the digestion of bread and other things, have often been made on persons unaccustomed to such foods, or the foods have been given in excessive quantity. To those accustomed to it good wheatmeal bread is much pleasanter, more satisfying, and better flavoured than white; indeed, the latter is described as insipid. Most bakers' bread is of unsatisfactory quality. Flour and bread contain very little fat, the absence of which is considered a defect. This is remedied by the addition of butter, fat or oil, or by nuts, &c., which are rich in oil. These may be mixed with the flour prior to cooking, or used afterwards.

Oats contain a substance called avenin, apparently an alkaloid, which has an irritating action; the quantity is variable. It is to this that the so-called heating effect of oatmeal on some persons is due.

Prepared Cereals or Breakfast Foods.--Analyses were made of 34 of these cereal preparations by Weems and Ellis (Iowa State College Agricultural Bulletin, 1904). They report that the foods possess no nutritive value in excess of ordinary food materials; that the claim made for many pre-digested foods are valueless, and no reliance can be placed on the statement that they are remedies for any disease.

Oatmeal and other cereals are sold in packets as being partially cooked. We do not doubt that they have been subjected to a dry heat, but this has scarcely any effect on their starch and other constituents. The difference is a mechanical one. In rolled oats the grains are so cracked and broken, that on boiling with water, the water readily penetrates and more quickly cooks them throughout. There are other prepared cereal foods, but we doubt whether they are thoroughly cooked after the short boiling directed on the labels. They are a great convenience where it is difficult to get the time necessary for cooking the ordinary cereals. Coarsely ground wheat is too irritating when made into porridge, but there are some granulated wheats sold in packets, which are quite suitable. The Ralston breakfast food is excellent. They are rich in the phosphates and salts, found in the outer part of the grain. One cereal preparation called Grape Nuts, has had its starch converted into maltose and dextrin (maltose being a sugar), by a scientific application of the diastase of the grain. It is consequently easier of digestion and requires no cooking. It is beneficial for some forms of indigestion. There are several competing foods of less merit, the starch being less perfectly changed; one at least of which is objectionably salt. Properly cooked starch is readily digested by healthy persons, and for them malted food is of no special value.