little damage may be done. If repeated often, and allowed to go on uncared for, the whole structure of the car will suffer and the life of the machine be shortened.

It does not follow that the car will come to a standstill. It will continue to run, but badly. For like every other engine, it has the faculty of compensation. That is to say, when one part is out of order other parts will take on some of its work, and help, for a time at least, to make good the deficiency.

For instance, in a four-cylinder car one of the cylinders may cease to act. Yet the other three will take on a certain part of the work, and help to some extent to make up the deficiencies of the faulty one.

This will be only for a time, however, for the additional strain will slowly but surely have a bad effect on the rest of the engine, and through it on the other parts of the machine. One by one these will give way, and have to be compensated in turn. If still neglected and left to take care of itself, there will come a time when so many sections are affected, that the remainder cannot overcome the mischief, and compensation will fail. The car will become practically useless. Perhaps, like the one-hoss shay, it will collapse en masse. It has gone beyond the stage of running badly, it has broken down.

The human system is much like a motor-car, in that it consists of a vast number of parts acting in unison. Yet it is infinitely more wonderful, for it is much more complicated, and can create its own supply of energy. It is made, roughly speaking, of a framework of bone and muscle, a delicately-adjusted alimentary system, whereby it takes in and assimilates food, and of a circulatory apparatus which drives blood and nourishment to all parts of the body. It contains also a nervous system, compared with which these other parts are crude, mechanical contrivances. For it is on their nervous supply that they depend for their usefulness. Cut the nerves that go to a limb, and the finest muscles in the world are as helpless as the meat in a butcher’s shop. Deprive the heart of its nerve supply for a single minute, and it will never beat again.

Yet we pay vastly more attention to a weak heart, as it is called, or still more so to a broken leg, than we do to a threatened failure in the nervous system, which outweighs them all in importance. Once that has got out of order, the driving power is gone. Not only the heart and muscles, but every other faculty we possess loses its energy and usefulness.

So closely allied, however, are the different parts, that the nervous system itself, which governs all else, is dependent for its welfare on the very organs it governs. Like the power of a king, it rests not only on its own intrinsic qualities, but also on the strength and harmony of the units over which it rules.

And there is a constant interplay going on between the various parts of the body. No one organ or system can stand alone. If it is working badly, it affects other parts, and disturbs the harmony on which the health of the whole depends.

One of the most marked examples of this is to be found in the action and reaction which take place between the digestive organs and the nervous system. The presence of congenial company at meal-times is one of the best aids to digestion; a cantankerous discussion is the very opposite. Similarly, if a man sits down to his dinner with a grievance or a worry on his mind, it is safe to predict dyspepsia.

A lady once received a telegram containing disastrous news just as she was finishing a meal. Up to that time she had never known what indigestion was, yet for the next couple of days she suffered from it in a most acute form. The nervous shock had thrown the stomach out of order, inhibiting the secretion of gastric juice.

We cannot help troubles of this sort, but it is only once in a lifetime, perhaps, that we get a message of that sort during the progress of a meal. It is to be feared, however, that it is of almost daily occurrence for some people to sit down to table worrying over the business of the day. And the accumulated effects of these minor disturbances may in the long run prove more detrimental than one big one.

Conversely, the stomach has an equally potent influence over the nervous system. Everyone knows that when their digestion is out of order, and they are feeling uncomfortable or bilious, their heads are not so clear as usual. And with this there is a feeling of langour and irritability, and a difficulty in doing work efficiently. This is because the body fails to get its proper supply of nourishment, and also because it is poisoned at the same time. In order to understand the manner in which this is brought about, it is necessary to know something as to the events which are taking place throughout the body every moment of our lives.

When food is taken it is first digested and then passes out of the stomach, and is carried by means of the circulation to all parts of the body. It nourishes the various tissues, replacing the loss which is constantly going on.

For there is throughout the whole system a process corresponding to combustion, and this combustion, like the furnace of an engine, is the source of our energy.

As in an ordinary fire, ashes are produced in the form of waste matter of a poisonous nature. This waste must be removed from the tissues, else it interferes with the process, as a neglected fire is apt to become choked up and burn badly.

This removal is also accomplished by the circulation. In any community you may see on any ordinary working day two sets of carts, those belonging to tradesmen which distribute groceries and vegetables, and the scavengers’ carts which gather up the refuse. The same processes go on in the human body, with the difference that in this case the same agency which brings the supplies also carries away the waste.

These impurities are eliminated from the body by means of the lungs, the skin, the kidneys and bowels. And in order that this elimination may be sufficient, the circulation must be maintained in all parts of the body. Unless the blood is kept moving, this waste matter will tend to collect somewhere or other and give rise to trouble. The way in which this motion is kept up is by exercise, which squeezes out the fluid like an automatic sponge. If the body was kept perfectly still for weeks, it would became loaded with this impure material, as a room that is shut up is found to collect, in such a surprising manner, dust and dirt.

When it reaches the lungs it is purified by means of the air. For the air which we exhale is very different from that which is breathed in, the former being charged with impurities. The drowsy feeling which we experience in a crowded, ill-ventilated room is due entirely to the influence of these toxic gases. The purer the atmosphere we breathe, the more effective it is in carrying off impurities from the blood, so that fresh air and hygiene are essential to health, whilst exercise acts as a valuable adjunct by increasing the respirations.

Yet exercise itself, important as it is, needs to be carried out in moderation. For the muscles, whilst fulfilling the vital functions just enumerated, produce a poison of their own, if exertion be too violent or prolonged. The severe cramp from which athletes are liable to suffer is due to an accumulation of this toxin.

This poison is eliminated from the system during repose, and especially during sleep. Rest is therefore as requisite as exercise itself, and unless the body gets regular rest and sufficient of it, severe damage may result. The muscles