CHAPTER VI.

AUTOMATISM IN EXERCISE.

Movements Performed without the Intervention of the BrainDecapitated Animals-A Curious Spectacle Invented by the Emperor Commodus-Organs which Perform their Functions Automatically-Unconscious Movements-Office of the Spinal Cord-Conditions of Automatism in Exercise - Influence of Rhythm; Movements with a Cadence-Dancing Tunes-Influence of Apprenticeship-Necessity for Absence of Effort in Automatic Movements-Regularity of Automatic Actions-A Personal Observation: Automatism in Rowing-Persistence of Automatic Actions Memory" of the Spinal Cord - How Different Paces are Created-Tenacity of Early Muscular Habits -Quickness in Fencing-Race Horses Trained too SlowlyEffects of Automatism in Exercise - Economy of Voluntary Nervous Energy - The Brain supplemented by the Spinal Cord -Repose of the Psychical Faculties-Superiority of Automatic Exercises in Cases of Cerebral Fatigue.

We have tried to show in the preceding chapter how the brain and the psychical faculties can play an important part in bodily exercises. It remains for us to show here that muscular work may sometimes, on the contrary, be performed independently of the brain and without the intervention of the will.

We must first recall the fact that the brain is not indispensable to the performance of certain movements. The spinal cord suffices in certain cases to throw the muscles into action, for it is a nerve-centre, and consequently a focus of independent motor activity. But the movements due to the unaided action of the spinal cord have a peculiar character: they are involuntary. The will in fact has a direct action only on the cells of the brain, and cannot influence the independent activity of

the spinal cord. This latter is only excited by reflex action.

In reflex movements the will is no longer the stimulus of the muscle: the latter contracts under the influence of a sensory impression.

Let us suppose that an afferent nerve is aroused by a powerful sensation. The excitement is conducted by the nerve-fibre to a central cell in the spinal cord, from which a motor nerve arises. This cell is at once the termination of the sensory nerve and the origin of the motor nerve. It may happen that the sensory impression, instead of travelling towards the head to awaken the conscious faculties, stops in the motor cell of the spinal cord. The latter then sends it on as a motor stimulus to a muscle. The impression is reflected in the motor cell of the spinal cord, as the sonorous waves of the voice are reflected from a wall and give rise to an echo. We may say without straining the analogy that a reflex movement is the echo of a sensory impression.

In general, reflex movements are very simple and seem to be regulated by the intensity and duration of the stimulus which excites them-as often as we pinch the foot of a decapitated frog, so often is there a slight flexion of the limb-but it may happen that reflex movements are more complicated, and that a single stimulus gives rise to a whole series of muscular actions. It then seems that a simple impression awakens in the spinal cord the memory of a great number of movements which have often been performed; just as a single word will awaken in the brain the memory of a whole series of ideas. Thus the contact of the foot with the ground will produce the whole series of the movements of walking. The living being can then walk, and even run, without his brain taking any part in the muscular action.

A fact of Roman history, reported by Mosso in his book on "Fear" gives us a curious proof of the automatic power of the spinal cord. The emperor Commodus gave to the people of Rome a spectacle which was much appreciated. He let loose in the circus ostriches which were excited to run, and, when they

were at full speed, their heads were cut off with spears with a semilunar end. The decapitated animals did not fall at once, but continued their course to the barriers of the circus.

What we observe in a decapitated animal running, gives us a faithful picture of what is going on in an absent-minded man whose legs automatically perform the movements of walking, while his brain is otherwise occupied than in the action he is performing. In automatic movements what happens is that a series of reflex actions are substituted for actions which were at first voluntary. The brain, after having combined a movement, and determined its rapidity and rhythm, seems at the end of a certain time, to delegate its powers to the spinal cord; it little by little loses its interest in the performance of the action, and only comes into play when some new and peculiar circumstance demands a change in the direction, the energy, or the speed of the move

ments.

I.

Automatism is the faculty, possessed by certain nervous elements, of putting the muscles in action without the intervention of the will. Many organs of the body have the power of working automatically; the heart for instance has movements over which we have no control; the frequency of its beats is independent of our will.

Automatism is not however always absolute, and many organs can, according to circumstances, obey the orders we give them, or on the other hand, move without our being aware of the fact. Thus we breathe involuntarily even when asleep, but we can at will quicken, slacken, or suspend the respiratory movements.

The movements of the muscles of animal life may present, like those of organic life, an automatic character. The limbs and the body move when we are asleep without the intervention of the will, and in the waking state numerous complicated actions are performed unconsciously. A man much occupied in thought will get up without thinking, walk to and fro without noticing it,

and perform absently numerous movements of which he has remembrance. These are automatic

actions.

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The movements of walking are, of all muscular actions, those which most easily become automatic. Everyone must have noticed how easy it is for the brain to be otherwise engaged and to take no part in the work of the legs when we are walking; we can discourse, reflect, and even compose verses while walking. It will, however, be difficult to help thinking of the muscles in action when circling the trapeze, or fencing. The more difficult an exercise, the more marked the intervention of the will, and the more mental concentration is needed in its performance. But the exercises which were most difficult at first, come in the end to be performed automatically by practice. All the horsemen who pass by, rising so gracefully in their stirrups at each step of the horse, perform this movement without giving it the least attention, and surrendering their bodies to an entirely automatic movement. If you wish to know how their brains were exercised when they were learning to rise in their stirrups, watch a novice out for a Sunday ride stiffly perched upon his hired hack, endeavouring in vain to "identify" himself with the movement which jolts him, and bearing witness, by the contraction of his face, to the profound mental strain to which he is subject.

The first condition needed for an exercise to become automatic and to be performed without any effort of attention, is that it should be perfectly known, and that its apprenticeship should long ago have terminated.

That an exercise may be performed without the intervention of the conscious faculties, several other conditions are necessary, and in the first place the absence of effort. We know that effort is a contraction of the whole body, whose object it is to compress energetically all the bones of the skeleton, in order to form of these various movable pieces a rigid whole, able to give a solid point of application to the muscles in action. It is impossible to preserve perfect freedom of mind when making an

effort. The muscles, obliged to contract with all possible energy, seem to turn to their advantage cerebral nervous energy.

A man who puts his whole strength into a movement of any kind feels himself completely absorbed in his effort, and loses temporarily the consciousness of what is going on around him. If some one speaks to you at the moment when you are trying to measure your utmost strength with a dynamometer, you only preserve a confused recollection of the words which fall upon your ears, your conscious faculties were otherwise occupied and were distracted by the effort: so true is it, that mental actions and muscular actions, although so different in their essence, are often performed with the aid of the same instrument. It seems that the brain, an instrument of muscular as well as of mental work, is engrossed by the muscles when the latter have to employ their whole strength; hence thought has not free play, and cannot be as clear as usual. This taking possession of the brain by the muscles explains the usual want of intelligence of athletes and of men who do heavy work. The brain of a man who has made too many muscular efforts is a blunted tool which is no longer fitted for mental work.

There are then two essential conditions that muscular work may become automatic; these are long practice in the exercise performed, and moderation in the muscular effort it demands.

There are many other circumstances which favour automatism, and allow work to be performed without the intervention of the will. The subject has not been as yet methodically studied, nor has any one hitherto endeavoured to deduce from this curious phenomenon of automatism, the practical conclusion which would be valuable in considering the hygienic application of muscular exercise.

There is a fact of observation which is difficult to explain, but the truth of which every one will admit; this