Pleasant Ways in Science

by Richard A. Proctor

But we have to consider the other mineral constituents of the system.

If I were to run through the list of all the minerals which exist within the body, I should weary the patience of the reader, and perhaps not add very much to the clearness of his ideas respecting the constitution of the human frame. Let it suffice to state generally that, according to the calculations of physiologists, a human body weighing 154 pounds contains about 17½ pounds of mineral matter; and that the most important mineral compounds existing within the body are those which contain lime, soda, and potash. Without pretending to any strictly scientific accuracy in the classification, we may say that the lime is principally found in the bones, the soda in the blood, the potash in the muscles; and according as one or other of these important constituents is wanting in our food, so will the corresponding portions of the frame be found to suffer.

We have a familiar illustration of the effects of unduly diminishing the supply of the mineral constituents of the body in the ravages which scurvy has worked amongst the crews of ships which have remained for a long period ill-supplied with fresh vegetables. Here it is chiefly the want of potash in the food which causes the mischief. An interesting instance of the rapid—almost startling—effects of food containing potash, in the cure of men stricken by scurvy, is related by Dana. The crew of a ship which had been several months at sea, but was now nearing the land, were prostrated by the ravages of scurvy. Nearly all seemed hopelessly ill. One young lad was apparently dying, the livid spots which were spreading over his limbs seeming to betoken his rapidly approaching end. At this moment a ship appeared in view which had but lately left the land, and was laden with fresh vegetables. Before long large quantities of the life-bearing food had been transferred to the decks of the other ship. The instincts of life taught the poor scurvy-stricken wretches to choose the vegetable which of all others was best suited to supply the want under which their frames were wasting. They also were led by the same truthful instincts to prefer the raw to cooked vegetables. Thus the sick were to be seen eating raw onions with a greater relish than the gourmand shows for the most appetising viands. But the poor lad who was the worse of the sufferers had already lost the power of eating; and it was without a hope of saving his life that some of his companions squeezed the juice of onions between his lips, already quivering with the tremor of approaching death. He swallowed a few drops, and presently asked for more. Shortly he began to revive, and to the amazement of all those who had seen the state of prostration to which he had been reduced, he regained in a few days his usual health and strength.

The elements which we require in order to supply the daily waste of the mineral constituents of the body are contained in greater or less quantities in nearly all the articles which man uses for food. But it may readily happen that, by adopting an ill-regulated diet, a man may not take a sufficient quantity of these important elements. It must also be noticed that articles of food, both animal and vegetable, may be deprived of a large proportion of their mineral elements by boiling; and if, as often happens, the water in which the food has been boiled is thrown away, injurious effects can scarcely fail to result from the free use of food which has lost so important a portion of its constituent elements. Accordingly, when persons partake much of boiled meat, they should either consume the broth with the meat, or use it as soup on the alternate days. Vegetables steamed in small quantities of water (this water being taken with them), also afford a valuable addition to boiled meat. In fact, experience seems to have suggested the advantage of mixing carrots, parsnips, turnips, and greens with boiled meat; but unfortunately the addition is not always made in a proper manner. If the vegetables are boiled separately in large quantities of water, and served up after this water has been thrown away, more harm than good is done by the addition; since the appetite is satisfied with comparatively useless food, instead of being left free to choose, as it might otherwise do, such forms of food as would best supply the requirements of the system. Salads and uncooked fruits, for instance, contain saline ingredients in large proportion, and could be used advantageously after a meal of boiled meat. Potatoes are likewise a valuable article of food on account of the mineral elements contained in them. And there can be no doubt that the value of potatoes as an article of food is largely increased when they are cooked in their skins, after the Irish fashion.

Lastly, we must consider those articles of food which promote the natural vital changes, but do not themselves come to form part of the frame, or, at least, not in any large proportion of their bulk. Such are tea, coffee, and cocoa: alchoholic drinks; narcotics; and lastly, spices and condiments. We may compare the use of these articles of food to that of oil in lubricating various parts of a steam-engine. For, as the oil neither forms part of the heat-supply nor of the force-supply of the steam-engine, nor is used to replace the worn material of its structure, yet serves to render the movements of the machine more equable and effective, so the forms of food we are considering are neither heat-producing nor flesh-forming, nor do they serve to replace, to any great extent, the mineral constituents of the body, yet they produce a sense of refreshment accompanied with renewed vigour. It is difficult to determine in what precise way these effects are produced, but no doubt can exist as to the fact that they are really attributable to the forms of food to which we have assigned them.

Tea, coffee, and cocoa owe their influence on the nervous system to the presence of a substance which has received the various names of theine, caffeine, and theobromine. It is identical in composition with piperine, the most important ingredient in pepper. It may be separated in the form of delicate white, silky crystals, which have a bitter taste. In its concentrated form this substance is poisonous, and to this circumstance must be ascribed the ill effects which follow from the too free use of strong tea or coffee. However, the instances of bad effects resulting from the use of “the cup which cheers but not inebriates” are few and far between, while the benefits derived from it are recognized by all. It has, indeed, been stated that no nation which has begun to make use of tea, coffee, or cocoa, has ever given up the practice; and no stronger evidence can be required of the value of those articles of food.

Of alcoholic liquors it is impossible to speak so favourably. They are made use of, indeed, almost as extensively as tea or coffee; they have been made the theme of the poet, and hailed as the emblems of all that is genial and convivial. Yet there can be little doubt that, when a balance is struck between the good and evil which have resulted to man from their use, the latter is found largely to preponderate. The consideration of these evils belongs, however, rather to the moralist than to the physiologist. I have here simply to consider alcoholic liquors as articles of food. There can be little doubt that, when used with caution and judgment, they afford in certain cases an important adjunct to those articles which are directly applied to the reparation of bodily waste. Without absolutely nourishing the frame, they ultimately lead to this end by encouraging the digestive processes which result in the assimilation of nutritive articles of food. But the quantity of alcohol necessary to effect this is far less than is usually taken even by persons who are termed temperate. It is also certain that hundreds make use of alcoholic liquors who have no necessity for them, and who would be better without them. Those who require them most are men who lead a studious sedentary life; and it is such men, also, who suffer most from excess in the use of alcoholic liquors.

It remains that I should make a few remarks on mistakes respecting the quantity of food.

Some persons fall into the habit of taking an excessive quantity of food, not from greediness, but from the idea that a large amount of food is necessary for the maintenance of their strength. They thus overtax the digestive organs, and not only fail of their purpose, but weaken instead of strengthening the system. Especially serious is the mistake often made by persons in delicate health of swallowing—no other word can be used, for the digestive organs altogether refuse to respond to the action of the mouth—large quantities of some concentrated form of food, such as even the strongest stomach could not deal with in that form. I knew a person who, though suffering from weakness such as should have suggested the blandest and simplest forms of food, adopted as a suitable breakfast mutton-chops and bottled stout, arguing, when remonstrated with, that he required more support than persons in stronger health. He was simply requiring his weak digestive organs to accomplish work which would have taxed the digestive energies of the most stalwart labourer working daily in the open air for many hours.

On the other hand, a too abstemious diet is as erroneous in principle as a diet in excess of the natural requirements of the system. A diet which is simply too abstemious is perhaps less dangerous than persistent abstinence from the use of certain necessary forms of food. Nature generally prevents us from injuring ourselves by unwisely diminishing the quantity of food we take; but unfortunately she is not always equally decided in her admonitions respecting the quality of our food. A man may be injuring his health through a deficiency in the amount either of the heat-forming or of the flesh-forming food which he consumes, and yet know nothing of the origin of the mischief. It may also be noted that systematic abstinence, either as respects quantity or quality of food, is much more dangerous than an occasional fast. Indeed, it is not generally injurious either to abstain for several days from particular articles or forms of food, or to remain, for several hours beyond the usual interval between meals, without food of any sort. On the contrary, benefit often arises from each practice. The Emperor Aurelian used to attribute the good health he enjoyed to his habit of abstaining for a whole day, once a month, from food of all sorts; and many have found the Lenten rules of abstinence beneficial. As a rule, however, change of diet is a safer measure than periodical fasting or abstinence from either heat-producing or flesh-forming food. It must be noticed, in conclusion, that young persons ought not, without medical advice, to fast or abstain for any length of time from the more important forms of food, as serious mischief to the digestive organs frequently follows from either course.