Popular Science Monthly/Volume 22/March 1883/A Few Words About Eatables
By C. B. RADCLIFFE, M. D.
CLERICUS. I have had a good breakfast.
Medicus. So have I.
C. I should not say so. I have emptied the toast-rack, and helped myself to three or four slices of cold roast-beef; you have had some galantine with brown bread and butter, and not much of them. But I suppose it is all right. I am going in for a hard day's boating; you are proposing to spend the clay at home in finishing the diagrams, or tables, which you are going to use to-morrow at the hospital in your lecture on eatables, and which are now very much in the way when I want to see the pictures on the walls, or to take a book from a book-case. What you have taken would not enable you to do my work.
M. I am not so sure of that. At all events I am quite sure of this—that you are not wise in eating so much lean meat, in picking out every scrap of fat, and in taking no butter.
C. I want muscular power, and I feed my muscles by eating lean meat, which is muscle. I am right, so far, I suppose?
M. The muscle must no doubt be fed to enable it to act, but you are not at liberty to suppose, as you do, that the amount of urea and other excrementitious nitrogenous matter in the urine supplies the measure of the waste of muscle in muscular action which has to be repaired by food. You must seek this measure, not in the amount of urea eliminated by the kidneys, but in the amount of carbonic acid exhaled in the process of respiration; and the facts with which you have to do go to show that, after all, this food you are taking may not be that which is most suited to your wants to-day. As is shown in one of the experiments in which Pettenkofer was assisted by Voit, and as you may see in one of the tables which hide the pictures and books here—thus, No. 1—the difference between a day of rest and a day of hard work, as regards the elimination of carbonic acid and urea, is marked not by an increase in the quantity of urea, but by an increase in the quantity of carbonic acid, the actual quantities being—
On the day of hard work there is a very marked increase in the quantity of carbonic acid, and a trifling decrease in the quantity of urea. What do you say to this fact? Again: As is shown in one of the experiments of Lehmann, and as you may see in this table, No. 2, the amount of urea eliminated by the kidney is, in the main, proportionate to the amount of nitrogenous matter contained in the food; the result of feeding a dog
Once more: As is shown by Edward Smith in an experiment upon himself, and as you may see in this table, No. 3, the amount of carbonic acid given off every minute is in direct proportion to the amount of work done in the time, the actual amount being—
Similar facts are supplied in numbers by these experimentalists, and also by Fick and Winceslaus, and Traube and Parkes, and Pavy, and other excellent observers in this country and abroad; but these three, about the correctness of which there can be no doubt, are sufficient to show that the amount of urea in the urine does not supply the measure of this waste of muscular tissue in muscular action, which has to be repaired by lean meat and other nitrogenous food, and that the food you really want to repair this waste may be carbonaceous rather than nitrogenous—simple fuel, rather than plastic material.
C. I shall, I expect, be quite ready for my dinner when I come back. I may have taken more lean meat than I wanted to keep my muscles in trim; I have not taken more than I seem to want. I have been breakfasting in this way for a long time, and I was never in better trim for a long pull than now. I may be eating too much, but you must allow that I am eating the best kind of food.
M. I do not say that you are not eating the best kind of food; I only say that lean meat is not the only kind of nitrogenous food which will serve your purpose. It is impossible to distinguish between the albuminose or peptone into which fibrine is resolved in the process of digestion and the albuminose or peptone into which albumen, or caseine, or gluten, or legumin, is resolved in this process. It is apparently of little or no moment whether these various nitrogenous articles of food are derived from the world of animal life or from the world of vegetable life. You must allow that an herbivorous animal is not less vigorous than a carnivorous animal; and certainly you would find it difficult to show that man, who can live and thrive under the most dissimilar circumstances upon almost any kind of food, is vigorous in proportion to the amount of meat he contrives to consume.
C. You can hardly wish to depreciate the nutritive value of lean meat.
M. Certainly not. All the nitrogenous substances, animal and vegetable, are resolvable into albuminose in the process of digestion, but not with the same facility in every case. Some of them are digested more easily by some persons than by others; and, besides, there may be differences in the albuminose itself which are recognizable by chemical means. In your own case, lean meat may be more digestible than any other nitrogenous compound, and the albuminose into which it is converted may be more easily assimilated. In another case, eggs or cheese or macaroni may better suit the requirements of the person taking it. I do not venture to lay down a hard and fast rule for you or any one in this matter; I only want you to understand distinctly that a person who can not get a full allowance of lean meat, or who does not choose to get it, is not necessarily ill fed for that reason, even though he have to do hard work with his muscles.
C. If a large amount of nitrogenous food is not wanted as food for muscle or other tissues—for plastic purposes, that is to say—how is the excess disposed of?
M. The part of the nitrogenous food which is not wanted for plastic purposes is, after digestion, resolved by the action of the liver into urea, and the other excrementitious products which are met with in the urine, and into a compound containing carbon, hydrogen, and oxygen, without any nitrogen, which compound may he the substance called amyloid substance or glycogen. This non-nitrogenous compound is destined to serve as fuel for the production of heat and other forms of force. The portion eliminated as urea, which is simply excrementitious, and the complemental portion, which is destined to serve as fuel, is as 33·20 to 66·80; and therefore it is easy to see that a large part of the nitrogenous food—but little less than two thirds, that is to say—may be devoted to other than plastic purposes, and that a little more than one third may be simply wasted. Moreover, the comparatively small portion of nitrogenous food which is actually wanted for plastic purposes is, there is reason to believe, eventually disposed of in the same way as the portion which is not used for plastic purposes, a little more than one third being wasted as urea, and a little more than two thirds being utilized as fuel. And if this be so, the question arises whether the fuel into which a large part of the nitrogenous form of food is resolved sooner or later is the best form of fuel for your purposes—whether, for example, you were wise in picking out the fat and in taking dry toast?
C. I leave you to find the answer to this question.
M. There is, I think, good reason to believe that much of the fuel without which life can not be maintained may be more easily supplied by non-nitrogenous substances than by nitrogenous substances. The fuel in nitrogenous food is not ready-made. This food has to be transformed, first of all, into albuminose or peptone, and then this albuminose or peptone has to be broken up, partly into the excermentitious portion which passes out of the system by way of the kidneys, and partly into the residual portion which is destined to act as fuel. An abundant supply of gastric and pancreatic and intestinal juices is wanted in order to bring about the proper formation of albuminose; without a healthy condition of liver and kidney it is evident that the albuminose may not be broken up (this breaking-up occurs chiefly in the liver) into urea and amyloid substance or glycogen, and that the urea (which passes out of the system by way of the kidneys) may not be eliminated. Moreover, it seems to be certain that no one can take a large amount of meat and other highly nitrogenous compounds for a long time unless lie also do a large amount of muscular work—unless he do much more work of this sort than the great majority of human beings are willing or able to do. Fat and butter and oily matter generally, on the other hand, require no digestion, in the proper sense of the word. They are converted into an emulsion—which is no more than a mechanical mixture like cream, by the action of the pancreatic and duodenal juices chiefly, and by the action of the bile partly, and this emulsion passes directly into the general circulation of the blood through the lacteals directly, without going the round of the portal circulation and the liver, as albuminose has to do. Fat and butter and oily matters generally are fuel ready-made, or which only need to be emulsified in order to be in this case; and they have this advantage also—that they are burned up in the system, without leaving behind them, so to speak, any ash like urea. And, as force-producing agents—if the capacity for oxidization may be taken as a measure—the value of fat and oil is almost double that of fibrine or albumen.
C. I can see that I may have been taking too much lean meat and too little toast; I can also see that I may have been especially wrong in avoiding fat and butter; but I do not see how to set to work to reform mv doings.
M. What you have to do, first of all, is to bear in mind that the daily loss which has to be made good by food, in a man of medium stature and in moderate work, amounts to 4,800 grains of carbon and 300 grains of nitrogen, and that, in round numbers, lean meat contains 11 per cent of carbon and 3 per cent of nitrogen, and bread 30 per cent of carbon and 1 per cent of nitrogen.
C. Is it so?
M. Yes. The daily rate of wasting of the system which I have mentioned is that which is brought to light by very many observations, carried on by many persons in various ways, with a view to regulate the food-rations of soldiers and sailors and prisoners, and other ration-fed people; and as to the proportion of carbon and nitrogen in lean meat and in bread the evidence is sufficiently conclusive.
C. Upon these data I can easily calculate how much meat and bread I really want if I choose to live wholly on meat or bread, and how the meat and bread ought to be apportioned if I take meat and bread together.
M. The calculation is ready made for you, and the result shows very plainly that you must mix your lean meat and bread in certain proportions if you care to feed without wasting good food. In order to replace the daily loss of 4,800 grains of carbon by lean meat, the quantity of meat you must take is 43,637 grains, or rather over 6 pounds a quantity which contains 1,009 grains of nitrogen in excess of the 300 grains actually wanted. In order to replace the daily loss of 300 grains of nitrogen by bread, the quantity of bread you must take will be 30,000 grains, or about 4 pounds—a quantity which exceeds by 25,200 grains the 4,800 grains of carbon which, are actually wanted.
C. My carnivorous tendencies, then, may not be so very extravagant, after all. I never ate 6 pounds of lean meat, or a third of that amount. I do not think I have suffered any sort of harm from the nitrogen which I may have taken in excess; I am sure I could never eat 4 pounds of bread, or half that amount, with impunity.
M. There is no occasion for you to eat these monstrous quantities of meat or bread. You must eat 6 pounds of lean meat every day if you take nothing else but lean meat; you must eat 4 pounds of bread every day if you take nothing else but bread; but you may get on very well upon a comparatively small allowance of meat and bread if the two were combined in proper proportions. You want every day 4,800 grains of carbon and 300 grains of nitrogen; you find what you want, as Dr. Pavy shows, in 2 pounds of bread and in about 4 pound of lean meat, thus:
C. I quite shrink from the notion of having to take so much as 2 pounds of bread to make up for the daily waste of my body.
M. You need not take so much, or anything like so much, if you will take fat with your meat, or butter with your bread, or any oily matter in proper quantity. Fat is very rich in carbon, and so are all fatty and oily matters. You would have the 4,800 grains of carbon and the 300 grains of nitrogen which you want, if you took 4 pound of lean meat and about 22 ounces of fat. In proportion as you increase the amount of fatty or oily matter, you may diminish the amount of bread; and, within certain limits, which you may determine for yourself, you may probably please yourself as to the relative proportions of the two. Whether you would get on satisfactorily by excluding bread altogether, and taking fatty matter in its stead, is another question. The growing chick within the egg has plenty of oily matter to feed upon, and nothing of the nature of starch or sugar, or any other carbo-hydrate to take the place of bread. The sucking mammal finds a large amount of oily matter in the milk upon which it feeds, and a somewhat larger amount of lactine, or sugar of milk, which, as a carbo-hydrate, may more or less take the place of bread. In the hen's egg, the proportion of fatty matter to albuminous matter is as 82 grains to 110 grains. In cow's milk the proportion of fatty matter to lactine is as 351 grains to 468 grains, and of these two substances in conjunction, together with caseine, as 811 grains to 369 grains. In 2 pounds of bread and 4 pound of lean meat the proportion of fatty matter to carbo-hydrates is as ·944 ounce to 16·320 ounces, and of both these substances together to nitrogenous matter as 17·264 ounces to 4·908 ounces. In point of fact, the proportions of nitrogenous matter, of fatty matter, of carbo-hydrates, and of mineral matter, in the dry constituents of a hen's egg, of a pint of cow's milk, and of 2 pounds of bread and 4 pound of lean meat, according to Dr. Pavy, are:
1. In the dry constituents of the contents of a hen's egg:
2. In the dry constituents of a pint of cow's milk:
3. In the dry constituents of 2 pounds of bread and 4 pound of uncooked lean beef:
C. By thus putting the composition of egg and milk side by side with that of bread and meat, the conclusion you would have me draw, I suppose, is, not only that fatty matter is present in large quantity in the two model forms of food, egg and milk, but also that fatty matter may be made to take the place of the starch and sugar of bread.
M. By comparing the composition of 2 pounds of bread and 4 pound of lean meat with that of eggs, you may also, I think, form some idea of the amount of fatty or saccharine matter which is necessary to replace the 2 pounds of bread. The nitrogenous matter of 6 pints of milk or thereabout is equivalent to that of 2 pounds of bread and 3 pounds of lean meat, for in 6 pints of milk there are 4·082 ounces of fatty matter and 6·416 ounces of lactine; and, therefore, you may conclude that the 4·082 ounces of fatty matter and 6·016 ounces of lactine which are present in the 6 pints of milk are equivalent, for practical purposes, to the ·944 ounce of fatty matter and to the 16·820 ounces of starch and other carbo-hydrates which are met with in the 2 pounds of bread and pound of lean meat. The nitrogenous matter of 20 eggs is about equal to that of 2 pounds of bread and 4 pound of lean meat, for in 20 eggs there are 1,600 grains, or 3·66 ounces of fatty matter, and therefore you may conclude that the 1,600 grains, or 3·66 ounces of fatty matter which are present in the contents of 20 eggs may take the place of its ·944 ounce of fatty matter which are met with in the 2 pounds of bread and in the 4 pound of lean meat, and of the 16·320 ounces of starch and the other carbo-hydrates which are present in the 2 pounds of bread. For it may be fairly assumed that the properties of the nitrogenous and nonnitrogenous compounds are as properly balanced in the egg and milk, which are the two great typical forms of natural food, as they are in the artificial combination of bread and meat of which we are speaking. You may draw your own conclusions from the tables on the walls in which these facts are set forth.
C. I also find in these tables a curious correspondence as to the amount of mineral matter in the three cases under consideration. The proportion of mineral matter in the other constituents is as 1 to 18 in the egg, as 1 to 17 in milk, and as 1 to 17 in the case of meat and bread.
M. This correspondence may not be quite so close as it seems to be. In the case of the egg an uncertain amount of lime, probably a large amount, ought to be added, for the shell becomes thinner and thinner as the process of incubation goes on, in consequence of the solvent action of the phosphoric acid which is generated by the oxidization of the phosphorus in the contents of the egg. In the case of white bread (white bread was used in this experiment) the greater part of the mineral matter, which is lodged chiefly in the husks of the grain, is sifted out in the preparation of the flour from which white bread is made. The earthy matter of the shell is certainly necessary to the proper development of the bones of the chick, and in all probability the bones are not the only tissues which are in this case. A dog lives long and thrives when it is fed upon brown bread, but not when it is fed upon white bread. Scurvy also is a speedy consequence of living upon salt meat, which differs from fresh meat chiefly in the fact that the salts belonging to it have been transferred to the brine. If the body is to be properly nourished, the mineral matters which are contained in the different articles of food can not be excluded, that is evident. And if these different articles of food are to be properly digested, the common salt, in the food or taken along with the food, may have a very important work to do in addition, for without it it is not easy to see how the gastric juice could acquire that part of its acidity which depends upon the presence of hydrochloric acid.
C. I have always avoided fat and butter, on the supposition that they would make me bilious and stout. I also thought that they were specially indigestible. I knew that they were of great value as heat producers, as "elements of respiration," as fuel, and that the inhabitants of cold countries could not get on well without an abundant supply of them, but it never entered into my head to suppose that they might take the place of meat and bread.
M. You have only to consider how olive-oil is used in the warm. parts of Europe where the olive is cultivated, and how ghee is used in India, in order to satisfy yourself that oily matter may be taken with facility in hot countries as well as in cold. You hear nothing about indigestion; you find that a bad olive-harvest or scant supply of ghee is a great national calamity. A Hindoo servant of a friend who kept up his Indian habits of eating here in London has often told me that in his own case nothing would make up for a deficiency of ghee or butter, and that his experience in this matter was the common experience of his countrymen at home or away from home. He looked upon a sip of ghee in very much the same light as that in which his fellow-servants looked upon a draught of beer. "Wine is good, but oil is better," said a peasant to the courier who was with me the other day in Andalusia, and after gulping down a large mouthful of olive oil and smacking his lips more than once, the expression of his countenance was an apt illustration of the meaning of the Scriptural text which speaks of oil as making "the face to shine." Indeed, it may be taken for granted that oil may be used in large quantities throughout the year in the hot, olive-growing countries of the south of Europe, not only without making the people bilious or out of order in any way, but with unmistakable benefit.
C. You have spoken of fat and butter and cream as force-producing agents. You mean heat-producing, I suppose?
M. No; I meant what I said. They are heat-producing agents without doubt, but heat is only one of several modes of force which are closely correlated, and there is reason to believe that the molecular movement which gives rise to heat in one case may, in another case, give rise to electricity or some other form of physical force. I do not believe that heat is transformed into muscular force or nerve-force. I believe that the oxidization of the force-fuel, which gives rise to heat in one case, may in the case of a muscle and nerve give rise to the electricity which is peculiar to muscle and nerve; that this electricity antagonizes the state of action in both muscle and nerve; that in muscle it also causes elongation of the fibers during the state of rest, and that muscular contraction is brought about by the action of the attractive force which is inherent in the physical constituents of the muscular molecules when this force is no longer antagonized by their electricity. Indeed, all that I want to bring about muscular contraction is, not a metamorphosis of muscle which issues in the development of muscular force, nor a transformation of heat into muscular force, but simply a supply of electricity during the state of muscular inaction which will counteract the tendency which the muscle always has to contract as an elastic body. I want, indeed, not a special muscular force, but merely the common attractive force which is inherent in the physical constitution of the muscular molecules, and electricity to counteract the working of their attractive force when necessary. C. I begin to see that I should have been in equally good trim for boating upon a very different kind of breakfast—that what I wanted was fuel for force-making rather than food for muscle-making; and now that I call to mind many facts which have been brought under my notice in countries where olive-oil is a staple article of food, I can, after what you have said about the connection of electricity with muscular action, understand how a man whose food is chiefly polenta or potato, with a little bread and oil, should have had as much muscular power at his disposal as ever I could contrive to compass. I once made the ascent of Etna with two Sicilian guides, who scarcely ever tasted any animal food except a morsel of fat bacon, and who lived chiefly on polenta and bread and olive-oil. More than once I thought I should never get to the top; they trudged upward with scarcely a sign of distress, though often having to expend a good deal of strength in pushing or pulling me up. And yet I was in what I thought to be an excellent "condition" at the time.
C. It is, I suppose, right to believe that most of the weaklings who are benefited in this country by cod-liver oil, in Switzerland by neat's-foot oil, and in Russia by train-oil, would never have required these oils as medicine if their food had been sufficiently rich in fatty and oily articles. Cod-liver oil, I have heard you say again and again, has no special virtue of its own; it does good simply because it is oil. In my parish, where cod-liver oil is now used, suet diffused in milk, by boiling the two together, was used formerly, and, I am told, with equal benefit. In the cases where cod-liver oil is wanted the food in all probability has been lacking in fatty or oily matter. More force fuel was wanted, I suppose.
M. I have a notion that the beneficial action of the fats and oils is not wholly to be accounted for by regarding them merely as force producers. I believe that they actually serve as food for nerve-tissue. This tissue is in the main made up of a peculiar kind of fat, and I am convinced that nerve is starved if the food be wanting in a sufficient quantity of fatty or oily matter. I find that very many persons suffering from various chronic disorders of the nervous system have abstained from the fatty and oily articles of food, and that their state is almost invariably very much changed for the better when you can get them to take what they have avoided; I also find that a great number of delicate infants who can not take skimmed milk, and who do not take kindly to unskimmed milk, will take milk without any difficulty when it is enriched with cream. You may say if you will, "These facts only show that the fatty and oily matters have done good in these cases by acting as force-fuel," and I do not care to contradict you flatly. Indeed, all I can say is that I do not think I am illogical in supposing that they may do good also in serving as food for nerve tissue. C. I gather from what you have said that you would prefer, as food for invalids, milk enriched with cream or some other fatty matter, or the yolks of eggs, or something like the bouillon of the French pot-au-feu, to highly nitrogenous preparations from which the fat has been carefully skimmed off, such as Brand's essence, or Liebig's extraction carnis, or ordinary beef-tea.
M. That I certainly do; lean meat more or less fluidified and its juices are not the sine qua non in food if what I have said be true. On the contrary, I am disposed to think that in very many cases foods of this sort are really unsuitable, if only by calling upon the liver to do work which this organ is unequal to at the time.
C. You approve, then, of the old-fashioned milk diet rather than of the meat preparations which are now so much in vogue?
M. I am quite a believer in the virtue of unskimmed milk as a most suitable food for invalids of all ages in almost all cases; and I think that, in very many cases where this fluid does not agree, this difficulty will be got over by the addition of cream or some fatty matter. I can imagine that many mothers who can not feed their infants in the proper way, or get fresh cow's milk or cream, will have reason to be glad when they can procure preparations of condensed or inspissated milk enriched with various quantities of cream or some fatty matter. I can imagine that preparations more or less similar to those, which, for the reason I have just hinted at, might properly be called brain-food or nerve-food, might make cod-liver oil almost superfluous as medicine, and be of infinite service to countless myriads of persons in whom brain-power or nerve-power is lacking. I can imagine that in many cases it will be difficult to find a food for invalids which is to be preferred to lightly boiled yolk of egg, or to ordinary egg flip. And in the cases where it is expedient to use flesh—meat in one form or another—I am sure it will be a great change for the better when, instead of having recourse to beef-tea, or Brand's essence, or Liebig's extraction carnis, the thoughts are turned to something like the bouillon of the French pot-au-feu, or rather to the very thing itself.
C. In what respect is this bouillon better than broth or stock?
M. It is much more pleasant to the taste. It is the outcome of ages of experience in the people who have a special genius for cookery. The animal and vegetable ingredients are so blended that the flavor of no one article is predominant. The bouillon contains all, or almost all, the soluble portions of those ingredients which are necessary for tissue-forming or plastic purposes, and for force-production, and, when taken along with bread, it provides a meal for an invalid which is most palatable, most digestible, and most restorative. It is the basis of all good gravies and soups, becoming, for example, excellent purée or pea-soup when a proper portion of pea-flour is added to it.
C. What about the bouilli which remains behind in the pot when the bouillon is poured out? This can not be of much use if all, or almost all, the soluble matters have found their way into the bouillon. Is it much more than mere padding?
M. The bouilli can not be of any very great value as food; and I am very much disposed to think that its place may often be supplied with advantage by bread or potatoes, or some other form of farinaceous food. For myself, I should infinitely prefer a basin of bouillon with bread, or a basin of purée with bread, to a basin of bouillon and a plate of bouilli after it, without bread; and I think my instincts do not mislead me in this matter. I have a small appetite, and no superabundance of digestive power; my inclinations turn toward vegetable food rather than toward animal food, and I can easily see that farinaceous food may be really more suitable to the wants of my system than anything which is left behind in the bouilli.
C. I have for years been trying to make the poor in my parish acquainted with the virtues of the bouillon and bouilli of the French ordinary pot-mi-feu, but it never entered into my head to suppose that the bouillon was ever to be preferred to the bouilli, or that bread, or potatoes, or pea-flour, or polenta might now and then be substituted for the latter with advantage. I have also been a good deal interested in an attempt which is being made by Messrs. Nelson, of Warwick, to introduce as cheap articles of food the inventions of our late friend Mr. J. R. Johnson, which are really properly made bouillon, and purée, and other soups in the form of dry chips. From a package of one of these preparations, which may be easily carried in a corner of the waistcoat-pocket, an excellent mess of bouillon or potage may be got in a few minutes with the help of a little water and fire, and I can easily see that the invalid and the working-man will both of them be great gainers in the matter of proper food, as well as in pocket, when this discovery is taken advantage of.
M. I, too, have been greatly interested in the articles to which you refer. I have tried the specimens which have been sent to me, and I highly approve of them. I think, indeed, that their introduction to the public marks a new epoch in the proper feeding of our countrymen, and that they will be made still more suitable for food when they are enriched to some extent by some form of fatty matter. I know how difficult it is to convince the poor of this country that all food is little more than padding except steaks, and chops, and cuts out of joints; and it will be long, I fear, before they can be persuaded to avail themselves of these preparations, or to learn to make for themselves the pot-au-feu of our neighbors across the Channel.
C. What else have you to say in the way of criticism about my unfortunate breakfast?
M. Only a word or two about bread and other farinaceous articles of food, and about the reason which made me prefer my gelatinous galantine of veal to your cold sirloin of beef. I think that bread may still be very properly spoken of as "the staff of life," and that other farinaceous articles of food may very properly be admitted into the same category with bread. The composition of wheaten-flour—which is more or less that of all flour prepared from cereal grain (oats, rye, barley, maize, rice, and the rest), and of leguminose seeds or pulse (peas, beans, lentils), and also of potatoes and some other tubers and roots—according to Dr. Letheby, is:
The nitrogenous matter consists of vegetable fibrine, albumen, and gluteine in the rough form of gluten. The fatty matter is in no way peculiar. The non-nitrogenous carbo-hydrates are starch, dextrine, sugar, gum, cellulose, and lignine—starch chiefly. The mineral articles comprise phosphates of lime and magnesia, salts of potash, and soda, and silica. Leguminose seeds or pulse contain as much as from twenty-five to thirty per cent of nitrogenous matter, mainly in a form of caseine called legumine; rice and potato contain as little as about eight per cent of nitrogenous matter, and as much as eighty per cent of starch, the amount of nitrogenous matter and starch in these articles of food being in an inverse ratio to each other. Fatty matter is especially abundant in oats and maize. It is evident, therefore, that there is much in these vegetable articles of food which may take the place of the nitrogenous and oily articles which are supplied in animal food.
There is no essential difference as to chemical composition between vegetable albumen, and fibrine, and legumine, and oily matters, and animal albumen, and fibrine, and caseine, and oily matters; there is no perceptible difference in the albuminose or peptone into which the vegetable and animal nitrogenous substances are alike transformed in the process of digestion; there is no difference in the way in which the vegetable and animal oily matters are emulsified, and then taken up directly into the general circulation of the blood. Nor is it difficult to see how the starch, and sugar, and other non-nitrogenous materials which are peculiar to vegetable bodies are disposed of within the system. The way in which starch is disposed of in the stomach and bowels is not very well made out, and all that can be affirmed with certainty is that a great part of it finds its way into the liver through the portal system of vessels, and is detained there for a time in the form of amyloid substance or glycogen—a detention which is not altogether unaccountable, for, as Dr. Pavy points out, this substance "possesses diametrically opposite physical properties to sugar, being a colloid, and therefore non-diffusible, instead of a crystalloid and diffusible." There is no sufficient reason to suppose that the action of digestion, be that what it may, is always to transform the starch into sugar; for sugar in quantity could not be formed in the stomach and bowels without passing directly into the general circulation, and so out from the blood into the urine by way of the kidneys—without making, that is to say, the phenomena of diabetes a natural state of things instead of an unnatural. Nor is there sufficient reason for supposing that the amyloid substance of the liver is transformed into sugar, for this substance is as readily oxidizable and as fit for force fuel as sugar. Nay, it may be questioned whether sugar itself is the force-fuel which the system is in need of. There is a very rapid generation of lactic acid in the stomach and bowels when sugar is taken as food, and it is not unintelligible that it should be so; for, with the help of a ferment of some sort, grape-sugar is readily converted into lactic acid. Indeed, all that has to be done is for one atom of anhydrous grape-sugar to split up into two atoms of lactic acid. Nor is it unintelligible that a certain part of the starch taken as food should pass, as it would seem to do, not into amyloid substance or glycogen, or into sugar, but first into dextrine, then into sugar, and then into lactic acid: for, as is seen in the list which I show you, there is a close chemical correspondence between these various substances and those which are akin to them. Thus:
There is no difficulty, therefore, in understanding, to some extent, how it is that, under the action of pepsin, or diastase, or some other ferment, starch, and dextrine, and cellulose, and lignine, and gum, and cane-sugar, and grape-sugar, and amyloid substance, may be transformed into the lactic acid which forms so important an ingredient in gastric juice, and that the lactic acid so formed, after having done its work in digesting nitrogenous substances, may be absorbed into the circulation directly, and be there disposed of in oxidization as a very readily inflammable fuel—perhaps as the more readily inflammable of all the force-fuels. And certainly there is no reason to believe that amyloid substance or sugar is more inflammable than lactic acid, but rather the contrary, for lactic acid can not be traced, as amyloid substance and sugar can be, beyond the limits of the alimentary canal. In any case I am, I think, at liberty to assume that a good deal of starch and sugar, and of the articles akin to them, are of great use in supplying lactic acid, and that this lactic acid has to do very important work, not only in the primary processes of digestion, but also as force fuel.
C. If this be so, the effect of taking sour buttermilk, sour milk, and sour whey—the sourness of which depends upon the presence of lactic acid—ought to be unequivocally beneficial in many cases.
M. So it is. I have long been in the habit of recommending these articles in cases where the digestive power is feeble and the circulation wanting in vigor, and I am quite satisfied that the practice is very satisfactory in its results. Instead of being "a weight to the stomach," as fresh milk often is said to be in these cases, these drinks are generally found to facilitate digestion and to keep up the warmth of the system. Indeed, by using sour buttermilk and sour whey, I have often found it possible to leave off doses like rum-and-milk, and to do without alcoholic drinks altogether.
C. I am prepared to believe what you say by what I know of the experience of those who take sour milk or sour buttermilk habitually, or who have tried the whey-cure. I have more than once heard an Irish peasant say that he misses the sour milk he takes along with his potatoes almost as much as the potatoes themselves, and that "it warms him like whisky and keeps off the rheumatiz." I have again and again felt myself benefited by taking buttermilk—by returning to what was a common practice in the district in which I spent my boyhood. And, certainly, I find it difficult to turn a deaf ear to all that I have heard in praise of the whey-cure in Switzerland and elsewhere by those who have tried it for dyspepsia and rheumatism.
M. I was led to recommend sour buttermilk or sour whey by reflecting on the very facts to which you refer.
C. What about the fattening effects of starch and sugar and other carbo-hydrates? Are these substances convertible into fat?
M. Possibly—nay, probably. At the same time I am disposed to think that in many cases the apparent transformation into fat is to be accounted for by the storing up in the system of the fatty and oily materials of the food—that these materials may remain behind by being, perhaps, less combustible than the lactic acid into which amylaceous and saccharine substances are naturally transformed.
C. You have still a word to say in justification of your preference for your gelatinous galantine.
M. The nitrogenous alimentary substances are divided into proteine compounds and non-proteine compounds. The former (the albuminous group) albumen, fibrine, caseine and their varieties, yield proteine when treated by heat and an alkali; the latter (the gelatinous group) containing gelatine and chondrine—gelatine prepared from bone and structures containing fibrous tissue, chondrine prepared from cartilage—does not yield proteine when so treated. Proteine is looked upon as the base or radical of the albuminous group; but it may only be an occasional chemical product. In any case it does not do to suppose that the non-proteine compounds forming the gelatinous group are useless as articles of food. The proteine and the non-proteine compounds are all reduced to albuminose in the process of digestion, and resolved afterward in the same way into urea and the residual force producing compounds which in all probability is amyloid substance or glycogen. An animal soon dies if it be fed solely on gelatine; and so it does also if it be fed solely on albumen, or fibrine, or starch, or sugar, or oily matter. The different elements of food, animal or vegetable, must be mixed in certain proportions, which are not yet very clearly made out, before an omnivorous animal can thrive upon them. There may be no occasion to take gelatine as food, for gelatine and chondrine are certainly formed in the system from any kind of albuminose; there can not well be any harm in taking it, for, as I have said, it is transformed into albuminose like any other form of nitrogenous substance; and there may be great good in taking it, for the coatings of the cells and fibers of muscle and nerve are made up of a structure like elastic tissue, which yields gelatine in abundance. Indeed, the popular notion that there is something specially strengthening in jelly may not be altogether a fallacy. I can easily believe that the gelatine may be wanted to provide for the proper nourishment of the coatings of the fibers and cells of nerve and muscle, and that a lack in this provision may bring about an abnormal disposition to involuntary action in nerve and muscle. I believe that these coatings are charged as the walls of a Leyden jar are charged during the state of rest, and that the degree of this charge and the indisposition to discharge is in proportion to the integrity of these coatings; in other words, I believe that the discharge which attends upon and produces this state of action, voluntary and involuntary, in nerve and muscle alike, is more likely to happen in the case where these coatings are insufficiently developed than in the case where they are sufficiently developed; and, so believing, you will easily understand why I think that gelatine may really be of high value as an article of food.—The Practitioner.