The Chemistry of Food and Nutrition Part 2

In the present state of society, when really good vegetarian fare is difficult to procure away from home, eggs, cheese, and milk are a great convenience.

Digestion.--The digestive juices contain certain unorganised ferments, which produce chemical changes in the food. If the food is solid, it has to be liquefied. Even if already liquid it has generally to undergo a chemical change before being fitted for absorption into the body. The alimentary ca.n.a.l is a tubular pa.s.sage which is first expanded into the mouth, and later into the stomach. As the food pa.s.ses down, it is acted upon by several digestive juices, and in the small intestine the nutritive matter is absorbed, whilst the residue pa.s.ses away.

The saliva is the first digestive juice. It is alkaline and contains a ferment called ptyalin. This acts energetically on the cooked and gelatinous starch, and slowly on the raw starch. Starch is quite insoluble in water, but the first product of salivary digestion is a less complex substance called soluble-starch. When time is allowed for the action to be completed, the starch is converted into one of the sugars called maltose.

In infants this property of acting on starch does not appear in effective degree until the sixth or seventh month, and starch should not be given before that time. Only a small quant.i.ty should be provided before the twelfth month, when it may be gradually increased. Dr. Sims Wallace has suggested that the eruption of the lower incisors from the seventh to the eighth month, was for the purpose of enabling the infant--in the pre-cooking stage of man's existence--to pierce the outer covering of fruits so as to permit his extracting the soluble contents by suction; and accordingly when these teeth are cut we may allow the child to bite at such vegetable substances as apples, oranges, and sugar cane. Dr. Harry Campbell says that starch should be given to the young, "not as is the custom, as liquid or pap, but in a form compelling vigorous mastication, for it is certain that early man, from the time he emerged from the ape till he discovered how to cook his vegetable food, obtained practically all his starch in such a form. If it is given as liquid or pap it will pa.s.s down as starch into the stomach, to setup disturbance in that organ; while if it is administered in a form which obliges the child to chew it properly, not only will the jaws, the teeth, and the gums obtain the exercise which they crave, and without which they cannot develop normally, but the starch will be thoroughly insalivated that much of it will be converted within the mouth into maltose. Hard well baked crusts const.i.tute a convenient form in which to administer starch to children. A piece of crust may be put in the oven and rebaked, and spread with b.u.t.ter. Later, we may give hard plain biscuits." Dr. Campbell continues, that he does not say that starch in the pappy form, or as porridge, should find no place whatever in man's dietary at the present day, but we should arrange that a large proportion of our food is in a form inviting mastication.

The teeth perform the very important function of breaking down our food and enabling it to be intimately incorporated with the saliva and afterwards with the digestive juices. The Anglo-Saxon race shows a greater tendency to degeneracy in the teeth than do other races; the teeth of the present generation are less perfect than those of previous generations. A dentist writes (_Lancet_, 1903-2, p. 1054) "I have had the opportunity of examining the teeth of many natives in their more or less uncivilised state, from the Red Indians of North America, the negroes of Africa, to the more civilised Chinese, j.a.panese, and Indians of the East, and I have usually found them possessed of sound teeth, but so soon as they come under the influence of civilised life in Was.h.i.+ngton, Montreal, London, Paris and other cities, their teeth begin to degenerate, though their general health may remain good." In a long article on mastication in the _Lancet_ (1903-2, p. 84) from which we have already quoted, Dr. Harry Campbell gives as the effect of thorough and efficient mastication, that it increases the amount of alkaline saliva pa.s.sing into the stomach, and prolongs the period of starch digestion within that organ. That it influences the stomach reflexly by promoting the flow of gastric juice.

That the frequent use of the jaws and the tongue, during the period of growth, cause the jaws to expand. If the jaws are not adequately exercised during this period, owing to the use of soft food, they do not reach their normal size, the teeth are overcrowded, do not develop fully, and are p.r.o.ne to decay. The effect of vigorous mastication is to stimulate the circulation in the tooth pulp, which promotes nutrition and maintains a firm dental setting. Dr. Campbell writes: "I am perfectly at one with Dr.

Wallace, in believing that the removal of the fibrous portion of food is the main cause of the prevalence of caries among moderns."

When the food reaches the stomach, gastric juice is secreted. This juice contains a ferment called pepsin and hydrochloric acid. Pepsin is only active in an acid media. Starch digestion proceeds in the stomach to such a time--stated as from 15 to 30 minutes--when the acid gastric juice has been poured out in sufficient quant.i.ty to neutralise the alkalinity of the saliva. The gastric juice acts upon the proteids only. After a time the liquefied contents of the stomach are pa.s.sed into the first portion of the small intestine, called the duodenum. Here it meets with the pancreatic juice, which like the gastric juice attacks proteids, but even more energetically, and only in an alkaline media. The proteolitic ferment is called trypsin. The pancreatic, the most important of the digestive fluids, contains other ferments; one called amylopsin, takes up the digestion of any remaining or imperfectly converted starch left from the salivary digestion. Amylopsin is much more powerful and rapid than the ptyalin of the saliva, especially on uncooked starch. Its absence from the pancreatic juice of infants is an indication that starch should not be given them. Another ferment, stearopsin, emulsifies fats. The bile is alkaline and a.s.sists the pancreatic juice in neutralising the acid mixture that leaves the stomach; it also a.s.sists the absorption of fats. The digestion of proteids is not completed in the stomach. There are some who look upon the stomach as chiefly of use as a receptacle for the large ma.s.s of food, which is too quickly eaten to be pa.s.sed at once into the intestines; the food being gradually expelled from the stomach, in such quant.i.ties as the duodenal digestion can adequately treat. A frequently used table, showing the time required for the digestion of various foods in the stomach, is of little practical value. There is ample provision for the digestion of food, there is a duplication of ferments for the proteids and starch. In health, the ferments are not only very active, but are secreted in ample quant.i.ties. The digestive or unorganised ferments must not be confused with the organised ferments such as yeast. The latter are living vegetable cells, capable of indefinite multiplication. The former are soluble bodies, and though capable of transforming or digesting some thousands of times their ma.s.s of food, their power in this direction is restricted within definite limits. Another and preferable name for them is enzymes.

The action of saliva on starch is powerfully r.e.t.a.r.ded by tea, this is due to the tannin. Coffee and cocoa are without effect. Tea infused for two minutes only, was not found to have sensibly less restraining effect than when infused for thirty minutes. On peptic digestion both tea and coffee had a powerful r.e.t.a.r.ding effect. When of equal strength cocoa was nearly as bad, but as it is usually taken much weaker, its inhibitory effect is of little consequence.

Bacteria are minute vegetable organisms, which exist in the dust of the air, in water and almost everywhere on or near the surface of the earth.

They are consequently taken in with our food. They exist in the mouth; those in carious teeth are often sufficient to injuriously affect digestion and health. The healthy gastric juice is to a great degree antiseptic, but few bacteria being able to endure its acidity. When the residue of the food reaches the large intestine, bacteria are found in very great numbers. The warmth of the body is highly favourable to their growth. They cause the food and intestinal _debris_ to a.s.sume its faecal character. Should the ma.s.s be retained, the bacterial poisons acc.u.mutate and being absorbed into the body produce headaches, exhaustion, neurasthenia and other complaints. Proteid matter, the products of its decomposition and nitrogenous matter generally, are especially the food of bacteria; this is shown in the offensiveness of the faeces of the carnivora, notwithstanding their short intestines, compared with that of the herbivora. Also in the difference of the faeces of the dog when fed on flesh and on a nearly vegetable diet. On a rich proteid diet, especially if it consists largely of flesh, the bacterial products in the intestines are greater than on a vegetable diet. On the latter such a disease as appendicitis is rare. Professor Elie Metchnikoff, of the Pasteur Inst.i.tute, thinks that man's voluminous and highly developed large intestine fulfils no useful purpose, and on account of its breeding a very copious and varied bacterial flora, could with advantage be dispensed with. He also has said that man, who could support himself on food easily digestible, has a small intestine which is disproportionately fully developed. Instead of having between 18 and 21 feet of small intestine, man might do with one-third of that length. According to him, there is a disharmony of our food and our digestive system. Referring to such views, and the desire of some surgeons to remove the vermiform appendix and portions of the intestines upon too little provocation, Sir W. Macewin, M.D., F.R.S. (_B. Medical Jrn._, 1904, 2 p. 874) says:--"Is this human body of ours so badly constructed that it contains so many useless parts and requires so much tinkering? Possibly I may be out of fas.h.i.+on with the times, as I cannot find such imperfections in the normal human body as are alleged. On the contrary, the more one looks into the human body and sees it work, the better one understands it and the more one is struck with the wondrous utility, beauty, and harmony of all its parts." Our food we can change, but not our organs-except by a dangerous surgical operations. Our teeth with our complex and very long intestines are adapted for fibrous, bulky and solid food. On such food mankind has lived for an immense period of time. It is true that there are several theoretical advantages in cooked vegetable foods; but unfortunately there is a want of conformity with our digestive organs. If a flesh diet is taken, the incongruity is greater. Concentrated food causes constipation. An active man, leading an out-of-door life, can take unsuitable food with little or no apparent inconvenience, the movements of his body favouring intestinal action; whilst the same food to a sedentary person will prove distinctly injurious.

Some persons have such a vigorous digestion that they can consume almost any food, even that which is obviously unsuitable; not only bad in kind but excessive in quant.i.ty. Other persons have to be very careful. Many have boasted that they can take of what they call the good things of life to their full, without bad effect. We know of such men who have been much esteemed for their joviality and good nature, but who have broken down in what should have been a hearty and useful middle life. There are others who were poorly equipped for the battle of life, with indifferent const.i.tutions, never having had the buoyancy and overflowing of animal spirits; but who, by conserving such strength as they had, have outlived all their more healthy but less careful comrades. The errors of the parents are often most evident in the children or grandchildren. There are many persons who cannot eat of some particular food, although it may be quite wholesome to others. Sometimes it is a psychological rather than a physiological disability, which may he overcome by an effort of the will. At other times it seems to have no connection with the imagination, although it is not always possible to give a sound reason for it. In the main, of course, there are principles of dietetics applicable to all alike, but in regard to details, everyone should make rules for himself, according to his experience. When there appears no real reason for an idiosyncrasy, a little humouring of our taste and digestion will often overcome it, to our advantage. It is generally those of delicate const.i.tution who are most sensitive. Some cannot eat oatmeal except in small quant.i.ty. Olive and other vegetable oils, even when of good quality cannot be taken by many people, whilst others find them quite as wholesome, or even better than b.u.t.ter. Vegetarians can generally detect lard in pastry both by its taste and its after effects, although those accustomed to this fat do not object to it. It is also surprising how some individual's tastes and habits will vary at different periods of their lives.

One form of dyspepsia is due to undigested starch remaining in the stomach and causing an excessive secretion of hydrochloric acid. As long as proteid food is present, the pepsin and acid expend themselves on it, and are removed together. The undigested starch continues to stimulate gastric secretion, and the acid residuum causes pain, heartburn and flatulence. If there be also any butyric acid, or some other fatty acid, derived from milk, b.u.t.ter, cheese, &c., there will be acid eructations. For this form of indigestion there are several methods of treatment. First; the very thorough cooking of all starchy food, and it is an advantage to take a little good extract of malt, either at the time of eating or directly afterwards. The diastase of the malt has the same action on starch as the ptyalin in the saliva. It is better, scientifically, to have the farinaceous food at about 130 F. (as hot as the mouth can bear will do), and then to add malt extract. On keeping the mixture warm, from a few minutes to half an hour or more, the starch is digested and rendered soluble. Such food is not very pleasant to take. The food known as Grape Nuts has been treated in a similar manner. The use of malt extract, however, seems a clumsy subst.i.tute for salivary digestion. Second; the eating of starch in the form of hard and dry biscuits, crusts and other hard food, which demand thorough mastication and insalivation, and the keeping in the mouth for a long while, during which the saliva has time to act. This is the best plan. Third; the taking of sodium bicarbonate towards the end of the period of digestion, in order to neutralise the acid in the stomach. This gives relief, but does not cure, as the dose has to be repeated after each meal; in course of time the quant.i.ty of soda has sometimes to be increased to an alarming extent. Fourth; the abstention from starchy foods and the subst.i.tution of an exclusive flesh dietary. In the "Salisbury" treatment, raw minced beef is given. This method often gives immediate relief, but its ultimate effect on the kidneys and other organs is very bad.

No hard and fast rule can be laid down as to the number of meals into which the daily amount of food required should be divided. The stomach appears to work to the best advantage when it is full, or nearly so, and the appet.i.te is appeased. Three approximately equal meals seems to be a convenient division. Dr. Dewey and his followers advise only two meals a day, and it seems incontestable that many persons find the plan advantageous. These are generally adults with weak digestions, or elderly persons who, on account of their age and the sluggish action of their a.s.similative functions, require comparatively little food. Children, on account of their vigorous vitality, rapid growth and hearty appet.i.tes, ought not to be restricted to this number. Persons who have got into the pernicious habit of greatly over-eating, and whose stomachs have become distended and unusually large, sometimes find it easier to restrict their daily food to a healthy quant.i.ty by taking only two meals. The general objections against two meals are that either two little food is taken, or the ingestion of such a large quant.i.ty is bad for the stomach and causes it to press on the adjacent viscera. The large quant.i.ty of blood and nerve force drawn to the over-distended stomach, depletes the brain and nervous system, causing drowsiness and incapacity for mental and physical work.

The carnivora, whose opportunity for obtaining food--unlike the herbivora--is irregular and often at long intervals, gorge themselves upon opportunity and are in the habit of sleeping after a meal. The frugivora and herbivora, however, are alert and ready to fly from their enemies should such appear. The conveying of so much nourishment to the liver and blood stream at one time, is probably a greater tax on them. A light lunch between the usual full meals has nothing to recommend it. The stomach is burdened to little purpose, often before it has finished with one meal another is imposed upon it, no time being left for recuperation.

Dietaries.--The best proportions of proteids, carbo-hydrates and fats required for the nourishment of the body has not yet been conclusively decided. The common plan is to average the dietary of large bodies of persons, particualrly of soldiers and prisoners. These dietaries have been adjusted empirically (the earlier ones at least), and are generally considered as satisfactory. They are chiefly of English and German origin.

Another method is to laboriously a.n.a.lyse the injesta or food consumed and compare it with the dejecta or excretions, until a quant.i.ty and kind of food is found which is just sufficient to keep the body in equilibrium.

This latter plan is the best, but to be quite satisfactory must be tried on a large number of suitable persons under varying conditions, both of quant.i.ty and kind of food. Nearly all the experiments have been made on persons accustomed to a stimulating dietary: their usual food has included a considerable quant.i.ty of flesh and alcoholic drinks. Sufficient attention has not been paid to the dietaries of the more abstemious races who partake of little if any flesh food. The standard daily dietary for a man of average weight, doing a moderate amount of work, is variously stated by the best authorities as proteids from 100 to 130 grammes, fat 35 to 125 grammes, and carbo-hydrates 450 to 550 grammes. There is a surprising difference of opinion on the amount of fat, but those who give least fat give the largest quant.i.ty of carbo-hydrate and _vice-versa_. Dr.

R. Hutchison in "Food and Dietetics," sums up the quant.i.ties given by the highest authorities as follows:---

Proteid 125 g. ( 4.4 oz.) x 4.1 = 512 cal. = 20 g. N, 62 C Carbo-hydrate 500 g. (17.6 oz.) 4.1 2050 200 Fat 50 g. ( 1.8 oz.) 9.3 465 38 ----------------- ---- -------- ----- 675 g.(23.8 ) 3027 Total 20 g. N, 300 C

The nutrient ratio is 1 : 4.9. For scientific purposes, metrical weights and measures are used, instead of the inconvenient English grains, ounces, pounds, &c. (1 gramme = 15.43 grains; 1 ounce avoirdupois = 437.5 grains = 28.35 grammes). A calorie is a measure of the power of a food in generating heat and muscular energy (these two being convertible).

The calories used in food tables are kilo-calories, representing the amount of heat which would raise a kilogramme (1000 grammes) of water 1 Centigrade. This is the same as raising 1 pound weight 4 Fahrenheit.

According to the table given, 125 grammes of dry proteid are required per day; this contains 20 grammes of nitrogen and 62 of carbon. When thoroughly consumed or utilised in the body, the heat or its equivalent in muscular work equals 512 kilo-calories. Proteids have, of course, an additional value as tissue formers. The factors used here, of 4.1 and 9.3, are those commonly employed; but the latest and most reliable research, taking account only of that part of the food which is actually available in the body, gives for proteid and carbo-hydrate 4 calories, and for fat 8.9 calories.

Fat has a higher food value than the carbo-hydrates, as 4.1 : 9.3 = 2.27 or 4.0 : 89 = 2.225, according to whether the old or new factors are used.

In the table of a.n.a.lyses 2.225 was used. The standard dietary for a woman, or of a boy 14 to 16 years of age, is given as equivalent to eight-tenths that of a man; a child of 10 to 13 six-tenths; of 2 to 5 four-tenths. A man doing hard work requires one-tenth more. The following table gives three standard dietaries, and a few actual ones, in grammes per day. The food of persons in easy circ.u.mstances, and of working men in the receipt of good wages, approximate to the standard dietaries, except that the fat is higher and the carbo-hydrates proportionately less. This is due to an abundance of animal food. It was thought unnecessary to give them in detail:--

Pr't. Fat. C'rb. Cal. N.R.

Hutchison: Man, moderate muscular work 125 50 500 3027 4.9 At.w.a.ter: " " " " 125 ... ... 3400 6.2 Voit: " " " " 118 56 500 2965 5.5 At.w.a.ter: Woman, light to moderate muscular work, or Man without muscular exercise 90 ... ... 2450 6.1 Football teams, Connecticut and California, U.S. 226 354 634 6590 6.6 Russian peasants 129 33 589 3165 5.4 Negro families--Alabama and Virginia 86 145 440 3395 9.3 Labourers-Lombardy (diet, mostly vegetable) 82 40 362 2192 5.5 j.a.panese, on vegetable diet (_a_) 71 12 396 2026 6.0 Trappist monk, in Cloisters-vegetable diet 68 11 469 2304 7.3 Java village--Columbia Exposition, 1893 66 19 254 1450 4.7 Sewing girl-London (3/9 per week) 53 33 316 1820 7.3 German vegetarians 54 22 573 2775 11.6 German labourers' family (poor circ.u.mstances) 52 32 287 1640 7.2 Dr. T.R.A.--wheatmeal bread and water only (_b_) 82 8.5 470 2342 6.0 Man--3 years' exclusively vegetable diet (_c_) 54 22 557 2710 11.2 Thomas Wood, the miller of Billericay (_d_) 55 5.7 313 1560 6.0

Dr. Alexander Haig considers that 88 grammes of proteid is required by a man leading a decidedly active life.

NOTES.--(_a_) The j.a.panese are of small stature and weight.

(_b_) One of a series of experiments by A.W. Blyth, 1888. 1-1/2 lbs. of wheatmeal per day was required for equilibrium; sedentary occupation, with a daily walk of six miles.

(_c_) See "A Text Book of Physiology," by M. Foster, 5th edition, part ii., p. 839; the diet was bread, fruit and oil. The man was in apparently good health and stationary weight; only 59 per cent. of the proteids were digested, leaving the small quant.i.ty of 32 grammes available for real use.

In commenting upon this, Professor Foster writes:--"We cannot authoritatively say that such a reduction is necessarily an evil; for our knowledge will not at present permit us to make an authoritative exact statement as to the extent to which the proteid may be reduced without disadvantage to the body, when accompanied by adequate provision of the other elements of food; and this statement holds good whether the body be undertaking a small or large amount of labour."

(_d_) The Miller of Billericay's case is quoted by Dr. Carpenter, and also by Dr. Pavy. It was reported to the College of Physicians in 1767 by Sir George Baker. A remarkable degree of vigour is said to have been sustained for upwards of eighteen years on no other nutriment than 16 oz. of flour, made into a pudding with water, no other liquid of any kind being taken.

A striking instance of abstemiousness is that of Cornaro, a Venetian n.o.bleman, who died in the year 1566 at the age of 98. Up to the age of 40 he spent a life of indulgence, eating and drinking to excess. At this time, having been endowed with a feeble const.i.tution, he was suffering from dyspepsia, gout, and an almost continual slow fever, with an intolerable thirst continually hanging upon him. The skill of the best physicians of Italy was unavailing. At length he completely changed his habits of diet, and made a complete recovery. At the age of 83 he wrote a treatise on a "Sure and certain method of attaining a long and healthful life." He says, what with bread, meat, the yolk of an egg and soup, I ate as much as weighed 12 ozs., neither more nor less. I drank 14 oz. of wine.

When 78 he was persuaded to increase his food by the addition of 2 oz. per day, and this nearly proved fatal. He writes that, instead of old age being one of weakness, infirmity and misery, I find myself to be in the most pleasant and delightful stage of life. At 83 I am always merry, maintaining a happy peace in my own mind. A sober life has preserved me in that sprightliness of thought and gaiety of humour. My teeth are all as sound as in my youth. He was able to take moderate exercise in riding and walking at that age. He was very pa.s.sionate and hasty in his youth. He wrote other treatises up to the age of 95.

k.u.magara, Lapicque and Breis-acher, have, as the result of their experiments, reduced the quant.i.ty of proteid required per 24 hours to 45 grammes. T. Hirschfeld states, as the conclusion of his research, that it is possible for a healthy man (in one case for 15 days and in another for 10 days) to maintain nitrogenous balance on from 30 to 40 grammes of proteid per day. Labbe and Morchoisne (Comptes Rendus, 30th May, 1904, p.

1365) made a dieting experiment during 38 days, upon one of themselves.

The proteid was derived exclusively from vegetable food. The food consisted of bread, lentils, haricots, potatoes, carrots, chestnuts, endives, apples, oranges, preserves, sugar, starch, b.u.t.ter, chocolate and wine. At the commencement, the day's food contained 14.1 grammes of nitrogen = 89.3 proteid, which was gradually diminished. On the 7th day 11.6 g. N. = 73.5 g. proteid was reached; during this time less N. was eliminated, indicating that the proteid food was in excess of that required for the wear and tear of the body. As the quant.i.ty of nitrogenous food was diminished almost daily, the N. eliminated was found to diminish also. This latter was in slight excess of that absorbed; but when a day or two's time was allowed, without further reduction in the food, the body tended to adjust itself to the dimished supply, and there was an approximation of income and expenditure. The smallest quant.i.ty of food was reached on the 32nd day with 1.06 N. = 6.7 proteid, which was obviously too little, as 2.19 N. = 13.9 proteid was eliminated. On the 21st day 4.12 N. = 26 proteid was injested, and 4.05 N. was eliminated. The inference drawn from the research is that about 26 grammes of proteid per day was sufficient. The weight of the body remained practically constant throughout, and the subject did not suffer inconvenience. Of course the full amount of calories was kept up; as each succeeding quant.i.ty of the proteid was left off, it was replaced by a proper quant.i.ty of non-nitrogenous food. These experiments were carried out in the usual approved scientific manner. It may, however, be urged against any generalised and positive conclusions as to the minimum quant.i.ty of proteid required for the body, being drawn from such experiments, that the period covered by them was much too short. A prolonged trial might have revealed some obscure physiological derangement. We are quite justified in concluding that the usual, so-called "standard dietaries" contain an unnecessarily large proportion of proteid. In some practical dietaries, 50 grammes and under have seemed enough; but for the ordinary adult man, who has been accustomed to an abundance of proteid, and whose ancestors have also, it is probably advisable not to take less than 70 or 80 grammes per day (2-1/2 to 3 ounces). If it is desired to try less, the diminution should be very gradual, and a watch should be kept for any lessening of strength.

Some comments may now be made upon the table of dietaries. That of the London sewing girl contained 53 grammes of proteid, which should have been ample, according to some of the authorities we have given; yet she was badly nourished. The food was doubtless of bad quality, and it appears deficient in carbo-hydrates; this latter is shown by the low number of calories. The long hours and unhealthy conditions of work, and not a deficiency of food const.i.tuents, is probably the cause of the bad health of such persons. There is no reason to think the proteid insufficient, although some persons have said as much. We have no particulars of the German vegetarians, but the calories appear satisfactory. In the poor German labourer's family the calories are too low. In Dr. T.R. Allinson's experiment on a wheatmeal dietary, it will not do to a.s.sume that less than 82 grammes of proteid would have been insufficient. It is probable that a smaller quant.i.ty of proteid would have been enough if the fat and carbohydrates had been increased. The calories are below the usual standard. In the succeeding example the calories are considerably higher, being not far from the usual standard, yet 54 grammes of proteid sufficed.

It is a common error to place an undue value on the proteids to the extent of overlooking the other const.i.tuents. Dr. Alexander Haig in "Diet and Food," p. 8, cites the case of a boy aged 10, fed on 2-1/4 pints of milk per day. The boy lost weight, and Dr. Haig is of opinion that the quant.i.ty of milk was very deficient in proteid; more than twice as much being required. 2-1/4 pints of milk contain about 45 grammes of proteid, whereas, according to the usual figures (125 x 6/10) a boy of this age requires 75 g. This quant.i.ty of 45 g. is however, higher, allowing for the boy's age, than that in several of the dietaries we have given in our table. A little consideration will show that Dr. Haig has overlooked the serious deficiency of the milk in the other const.i.tuents, which accounts for the boy's loss of weight. The quant.i.ty of milk contains only about 160 g. of total solid matter, whilst 400 g. is the necessary quant.i.ty. Milk is too rich in proteid matter to form, with advantage, the sole food of a human being. Human milk contains much less in proportion to the other const.i.tuents.

The old doctrine enunciated by Justus von Liebig was that proteid matter is the princ.i.p.al source of muscular energy or strength. He afterwards discovered and acknowledged his error, and the subject has since been thoroughly investigated. The makers of meat extracts and other foods, either from their own ignorance of modern research or their wish to take advantage of the lack of knowledge and prejudice of the public, call proteid matter alone nourishment. The carbo-hydrates and fats are equally ent.i.tled to be called nourishment.

Our reason for devoting so much s.p.a.ce to the consideration of the quant.i.ty of proteid matter required, is that in the opinion of many eminent writers it is the crux of vegetarianism. They have stated that it is impossible to obtain sufficient from vegetable foods alone, without consuming an excessive quant.i.ty of carbo-hydrates. We will summarise the argument as given in Kirke's Physiology, as edited by Morrant Baker, a standard work, and which is repeated in Furneaux's "Animal Physiology," a book which is much used in elementary science schools: "The daily waste from the system amounts to, carbon 4,500 grains (or 300 grammes), and nitrogen, 300 grains (or 20 grammes). Now let us suppose a person to feed on bread only. In order to obtain the necessary quant.i.ty of nitrogen to repair this waste he would have to eat nearly 4-1/4 lbs. daily.... He would be compelled to take about double the quant.i.ty of carbon required in order to obtain the necessary weight of nitrogen.... Next, let us suppose that he feeds on lean meat only. Then, in order to obtain the necessary quant.i.ty of carbon, he must eat no less than 6-1/2 lbs. daily.... In this case we notice a similar waste of nitrogen, the removal of which would give an undue amount of work to the organs concerned.... But it is possible to take such a mixed diet of bread and meat as will supply all the requirements of the system, and at the same time yield but little waste material." (These extracts are from Furneaux, the next is from Kirke. The figures and argument is the same in each, but we have chosen those sentences for quotation which are the briefest and most suitable; certain calculations being omitted.) "A combination of bread and meat would supply much more economically what was necessary ... so that 3/4 lbs. of meat, and less than 2 lbs. of bread would supply all the needful carbon and nitrogen with but little waste. From these facts it will be plain that a mixed diet is the best and most economical food for man; and the result of experience entirely coincides with what might have been antic.i.p.ated on theoretical grounds only." Professor Huxley, in his "Elementary Physiology" uses almost the same figures and argument.

The adoption of this high proteid or nitrogen figure would lead to some ridiculous conclusions. One writer states that 18 eggs would contain sufficient flesh forming substance for a day's ration, but a very much larger quant.i.ty would be required to supply enough carbon. On the other hand, Professor Church says that, no less than 70 lbs. of pears would have to be eaten per day, to supply the necessary quant.i.ty of nitrogen; although the carbon would be in excess. The curious may calculate the proper quant.i.ty of each that would make a theoretically perfect dietary.

People are apt to a.s.sume that what they themselves eat, or what their cla.s.s, race, or nation eat, is the proper and necessary diet; at least as far as the elementary const.i.tuents and quant.i.ties are concerned. The error is in attempting to make a vegetarian diet, however contrary to common sense and the experience of the greater part of the earth's inhabitants, agree in composition with the ordinary lavish flesh dietary of the well-to-do European. It is significant that John Bull is caricatured with a large abdomen and a coa.r.s.e, ruddy, if not inflamed face, indicative of his hearty dining on flesh, coa.r.s.e food and alcoholic drinks. An unhealthy short lived individual. Even if we accept a high proportion of proteid, it is possible to combine purely vegetable foods so as to give the required quant.i.ty of the various const.i.tuents, without a superfluity of the carbo-hydrates. In "Food Grains of India," Professor A.H. Church shows by elaborate a.n.a.lyses and dietary tables, how this can be accomplished by various combinations of cereals, pulses, etc. He takes Forster and Voit's standard of 282 grains of nitrogen and 5,060 grains of carbon, with a suitable deduction for the smaller weight of the Indians. In his examples of daily rations he gives from 5 to 9 ounces of various beans, balanced by the addition of the proper quant.i.ty of rice--4 to 16 ounces, and a little oil. Such a large quant.i.ty of pulse appears to us excessive, and would cause discomfort to most persons. We much doubt whether those Indians who are strict vegetarians could consume such quant.i.ties.

Some valuable investigations were made on the diet of a family of fruitarians, at the Californian Agricultural Experimental Station, July, 1900, by Professor M.E. Jaffa (bulletin 107). The proportion of food, both proteid and carbo-hydrate used was surprisingly small. The research is particularly important, as the diet was not an experimental one, tried during a short period only; but that to which the family were accustomed.

The family consisted of two women and three children; they had all been fruitarians for five to seven years, and made no change in their dietary during the experiment. They only had two meals a day, the food being eaten uncooked. The quant.i.ties of all the foods and other particulars are detailed in the bulletin. The first meal was at 10-30 a.m., and always consisted of nuts followed by fruits. The other meal was about 5 p.m., when they usually ate no nuts, subst.i.tuting olive oil and honey. The nuts used were almonds, Brazil, pine, pignolias and walnuts; the fresh fruits were apples, apricots, bananas, figs, grapes, oranges, peaches and pears.

Other foods were dates, raisins, pickled olives, olive oil and honey. One person (_b_) ate a little celery and tomatoes, and another (_c_) a little cereal food. In the following table are given the average daily quant.i.ties of the food const.i.tuents in grammes:--Proteids, fat, carbo-hydrate, crude fibre, value in calories and nutrient ratio. The crude fibre is cla.s.sed as a carbo-hydrate and included in the calorie value, and also in calculating the nutrient ratio.

Pro. Fat. C'r'b. Fibre. Cal. N. R.

Woman, age 33, weight 90 lbs. (_a_) 33 59 110 40 1300 8.6 Woman " 30 " 104 " (_b_) 25 57 72 27 1040 9.1 Girl " 13 " 75-1/2 " (_c_) 26 52 111 46 1235 10.5 Boy " 9 " 43 " (_d_) 27 56 102 50 1255 10.3 Girl " 6 " 30-1/2 " (_e_) 24 58 97 37 1190 11.1 Girl " 7 " 34 " (_ee_) 40 72 126 8 1385 7.4

The last research extended over ten days; the period during which each of the other subjects was under observation was from 20 to 28 days.

(_a_) The tentative standard for a woman at light work calls for 90 grammes of proteids and 2,500 calories; it is thus seen that the quant.i.ty of food eaten was far below that usually stated as being necessary. The subject, however, was a very small woman, 5 feet in height, taking almost no physical exercise. She believed, as do fruitarians generally, that people need far less raw than cooked food. (_b_) The food eaten was even less in quant.i.ty than in the previous dietary. One reason for this was the fact that the subject was, for part of the time at least, under great mental strain, and did not have her usual appet.i.te. Even this small amount of food, judging by her appearance and manner, seemed sufficient for her needs, enabling her to do her customary housework and take care of her two nieces and nephew, the subjects of the other experiments. (_c_) This girl was given cereals and vegetables when she craved them, but her aunt says she never looks nor feels so well when she has much starchy food, and returns to her next meal of uncooked food with an increased appreciation of its superiority. The commonly accepted dietary standard for a child 13 years old and of average activity, is not far from 90 grammes of proteids and 2,450 calories, yet the girl had all the appearance of being well fed and in excellent health and spirits. (_d_) During the 22 days of experiment, there was an increase in weight of 2 pounds, due to the fact that the family had been in straitened circ.u.mstances, and the food provided was more abundant during the study. (_e_) The subject had been very delicate as a baby. She was very small for her age, being 10 pounds under the average weight, and 7 inches less than the average height. It is interesting to note that her only gain in weight during the past year was made during this dietary and the one immediately following. This was due to her being urged to eat all she wanted, of what she most preferred, as the food was provided by those making the study. The proteid is less than the tentative standard for a child of 1 to 2 years old, but the subject appeared perfectly well and was exceedingly active. She impressed one as being a healthy child, but looked younger than her age. (_ee_) The subject is the same as in the previous experiment (_e_), but after an interval of 8 months, her seventh birthday occurred during the time.

Professor Jaffa, who made the investigation, says:--"It would appear that all the subjects were decidedly under-nourished, even making allowance for their light weight. But when we consider that the two adults have lived upon this diet for seven years, and think they are in better health and capable of more work than they ever were before, we hesitate to p.r.o.nounce judgment. The three children had the appearance of health and strength.

They ran and jumped and played all day like ordinary healthy children, and were said to be unusually free from colds and other complaints common to childhood. The youngest child, and the only one who has lived as a fruitarian almost from infancy was certainly undeveloped. She looked fully two years younger than she was. Still, there are so many children who are below the average in development, whose dietaries conform to the ordinary standards, that it would be unfair to draw any conclusions until many more such investigations are made."

The research shows that not only is there need of a revision of the "standard" quant.i.ty of proteids, but also of the carbo-hydrates and fats.

It is generally said by those who have no practical experience amongst vegetarians, that the latter require a much larger quant.i.ty of food than do those who include flesh. The truth is that vegetarians eat less, often much less. It is a common experience that vegetable food has a more staying power, and a much longer period can be allowed between meals, without the inconvenience that a flesh-eater, especially a flesh and alcohol consumer, suffers. This is due, in part at least, to its less stimulating character and its slower digestion. This fact has been shown by the success of vegetarians in feats of strength and endurance, and especially in the comparatively fresh condition in which they have finished long walking, cycling, tennis, and other matches. Those who attempt to prolong their powers of endurance by flesh extracts and stimulating foods and drinks, usually finish in a very exhausted condition. The superior endurance and recovery from wounds, when compared with our English soldiers, of simple feeding men, such as the Zulus, Turks and j.a.panese, has often been remarked. It is often said that vegetable food, as it contains more fibre and is slower of digestion, taxes the bodily organs more. If we attempted to eat uncooked, the more fibrous vegetables, the grains, and unripe fruit, it would be quite true, but it is not so of the ordinary food of vegetarians. A slowness of digestion does not necessarily imply a greater strain on the system. As vegetables, in particular, are for the longest period of time in the intestines, and undergo the greater part of their digestion there, a gentle and slow process of digestion in that organ may be more thorough. It may also entail less expenditure of nervous energy than if the food had been of such a stimulating character, as to be hurried along the digestive tract.

Digestion is for the most part a chemical process. If the food is of right kind and quant.i.ty, thoroughly masticated, a.s.sisted if necessary by cookery, and the digestive ferments are normal, digestion proceeds without any sensible expenditure or energy or consciousness of its accomplishment.

There is nothing improbable in a flesh-eater requiring more food than a simple living vegetarian. His food contains more proteid, and excrement.i.tious matter or extractives; these stimulate the digestive organs and overtax the excretory ones. Generally, he is fond of condiments, salt, and elaborate cooking, often also of alcohol; if a man, probably of tobacco. He lives, as it were, at high pressure.

There are on record certain experiments which appear to indicate the necessity of a large proportion of proteid, especially when the diet has been of vegetable origin. These experiments are inconclusive, because the subject has been accustomed to an ordinary flesh diet, perhaps also to alcoholic drinks. The change to a comparatively non-stimulating diet cannot be made, and the digestive organs expected to adapt themselves in a few days. Perhaps not even a month or a year would suffice, for some people, and yet that same diet would suit others. In some experiments the food has not been appetising, the subject has even taken it with reluctance or even loathing; an excess of some food has been eaten which no vegetarian or anybody else would think of using in a practical dietary.

Sometimes persons on changing from an ordinary flesh dietary, lose weight and strength. Generally, it is found that they have done little more than discontinue the flesh, without subst.i.tuting suitable foods. Authorities think it is from a deficiency of proteid, and recommend an addition of such foods as pulse, wheatmeal, oatmeal, eggs, milk, cheese, and such as a reference to the table of a.n.a.lyses, show a low nutrient ratio figure. This may also be due to an insufficiency of food eaten, owing to the comparatively insipid character of the food and want of appet.i.te. In making a change to a vegetarian diet, such foods had better be taken that are rather rich in proteid, and that approximate somewhat in their flavour and manner of cooking to that used previously. A further change to a simpler diet can afterwards gradually be made, according to conviction, tastes and bodily adaptability. It must not be expected that a change, even an ultimately very advantageous one, will always meet with an immediate and proper response from digestive and a.s.similative organs which have been accustomed for many years, perhaps by inheritance for generations, to another manner of living. There are several preparations produced from centrifugalised milk--that is milk from which the b.u.t.ter fat has been removed, which consist chiefly of proteid. These have a value in increasing the proteid contents of foods which may be thought deficient.

The addition of these manufactured products appear unnecessary, as most of our food contains an abundance of proteid, and we can easily limit the quant.i.ty or avoid altogether those that are thought defective.

The later apologists for a flesh diet have had to admit that it is not a physiological necessity; but they have attempted to justify its use by a theory somewhat as follows. It is admitted, that any excess of proteid over that necessary for its special province of producing tissue, is utilised as a force-producer, in a similar manner to the carbo-hydrates.

When the molecule is split up, and the carbon utilised, the nitrogen pa.s.ses off in the form of urea by the kidneys. The theory propounded is that at the moment the nitrogen portion is liberated, it in some manner stimulates the living protoplasm of the nerve cells in its immediate neighbourhood to a higher state of activity. These views are given by Dr.

Hutchison in his book on "Food," but there are no substantial grounds for them. It is only prompted by a wish to excuse a cherished habit. Sir William Roberts, M.D., in "Dietetics and Dyspepsia," p. 16 says that "high feeding consists mainly in a liberal allowance of meat, and in the systematic use of alcoholic beverages, and that low-feeding consists in a diet which is mainly vegetarian and non-alcoholic," and he proceeds to say that the high-fed cla.s.ses and races display, on the whole, a richer vitality and a greater brain-power than their low-fed brethren. That "it is remarkable how often we hear of eminent men being troubled with gout, and gout is usually produced either by personal or ancestral high-feeding." We can only spare room for a few remarks on this subject.

Intellectual and business ability brings wealth, wealth frequently leads to the pleasures of the table, but such habits are detrimental to sustained effort and clearness of mind. The children and grandchildren of such high livers are usually common-place, intellectually, and of deteriorated physique. The aristocracy who are generally high livers, notwithstanding their great advantages of education, travel and leisure, are not as a rule famed for their intellectual gifts. In the recent war the frugal living j.a.panese soldier has proved himself the most enduring and bravest in history; whilst the j.a.panese officers are more resourceful and tactful than the wealthier, high-fed Russian officers, with their aristocratic lineage. What is called high-feeding, is of the greatest benefit to the doctors and the proprietors of remedies for digestive and nervous disorders.