The commonwealth of cells

by H. G. F. Spurrell

In [Essay II.], which dealt with the chemistry of the body, we said that if we were only to live upon meat we should tax our digestive apparatus severely by having to eat more proteid than we required in order to get enough carbon. The converse, however, is equally true: if we fed only upon vegetables, we should again have to over-eat. Plants most of them contain large stores of carbohydrate; potatoes and rice are rich in starch, onions in sugar; but an exclusively vegetarian diet would necessitate our consuming huge quantities, as its proteid-supply is bad. It is defective not only in amount—for sometimes, as in beans, the proportion is fairly large—but in being so indigestible that a good deal of it passes through the body unabsorbed.

Both science and experience teach that we live most economically upon the carbohydrates of vegetables and the proteid of animals, and that our food is the better for being cooked. In cooking, parasitic animals which are strong enough to survive the ordeal by acid in the stomach are killed, and the food itself is made more accessible, the indigestible cellulose envelopes of the vegetable cells being burst open, and the collagen of the connective tissues converted into gelatin.

No less important than the quality of our food is the quantity; and here, again, we get a good illustration of the necessity for regarding the body as a whole. A healthy man’s appetite is his best guide, and if he follows it he cannot go far wrong. People who arrogate to themselves a wisdom superior to that of Nature little know the harm they do when they force food down an unwilling throat. The cells of the alimentary canal digest and absorb what is sent to them, minding their own business, which is not to criticise the appetite.

‘Theirs not to question why;

Theirs but to do and die.’

So the digestive and excretory systems embark on hard and profitless labour, and the whole body suffers.

Passing on to another subject, we find that the body eats that it may work, and works that it may eat. This cycle comes naturally enough to animals which have to go and find their food, but men with a sedentary occupation have, in view of the artificial conditions under which they live, to take constitutional exercise.

There are many reasons why the numerous and bulky muscles with which the body is endowed must be constantly used. In [the third essay] in this volume we saw that the flow of the lymph and the blood in the veins is largely dependent upon the movements of the limbs. Muscular exercise, therefore, must be taken to prevent the circulating streams from growing sluggish. Obviously, many evils must arise if they do so. Not only would the muscles be starved by the slowness with which they received their food, but they would also be poisoned by the slowness with which the products of their own metabolism were removed. The blood-stream would become tainted, and the brain, which requires pure blood, would suffer.

In other ways, however, than by their action on the vessels themselves do the muscles help the circulation. Exercise has secondary effects upon the circulatory and respiratory centres in the base of the brain, and makes the heart beat more strongly and the diaphragm contract more forcibly. The influence of the latter upon the circulation we have already described; but its vigorous action is required not only to aid the circulation through the liver and viscera, but to inflate the lungs to their fullest extent. In the breathing of a man who takes no exercise only a small part of the air which the lungs hold is pumped out at each breath, the greater part remaining stagnant in chambers which are practically unused. Thus, not only is the revenue of oxygen diminished, but there are numerous little crannies in the body filled with still, warm air which are ideal nurseries for bacteria. The devil of consumption does not allow such dwellings to long remain swept and garnished.

Without exercise the sweat glands of the skin will not act, and its pores get closed up. The muscular coats of the alimentary canal, too, reflect in their state of health the condition of the voluntary muscles; laziness is followed by constipation, for if the voluntary muscles rust, so do the involuntary.