undergone by the nerve-cells which preside over voluntary motion, just as intellectual fatigue is due to increased activity of the cells which are concerned in mental work.

Now, these two classes of cells are situated in the grey matter of the brain. It is then in reality the brain which supports the fatigue following exercises needing a great expenditure of nervous energy.

For this reason, fencing is unsuitable to men who study, and equally so to children who work their brains to excess, and it is the last exercise we should advise for very excitable temperaments, unless we have to provide food for unoccupied brains, for unquiet spirits whose activity consumes themselves, failing better occupation. In such cases fencing may become a precious derivative, by absorbing, as would mental work, the excessive nervous force which was tormenting the inactive mind.

Fencing, like all exercises which produce disturbances in the nervous system, is a most valuable exercise to persons who wish to get thinner. Among the most important functions of the nervous system is that of regulating nutrition; so we see all fatigue borne by the nerves, all excessive expenditure of nerve-force lead to diminished energy of the process of nutrition and favour the opposite process, thereby causing loss of weight.

Psychical disturbances, sustained emotions, through the waste of nervous energy which they occasion, hinder the nutritive functions, and lead to loss of weight. It is by an identical mechanism that the same result is produced after exercises needing a great expenditure of nervous energy. It is curious to see how animals whose mode of life necessitates movements similar to those of fencing have the privilege of escaping obesity.

Have you ever enquired how it is that cats can combine with their proverbial idleness such great agility? Muscular inaction leads just as much in other kinds of animals as in the human species to obesity; the dog which does not hunt, the horse kept in the stable, become fat and sluggish. Wild animals even, if kept in

a cage, where they are forced into the repose of domestic life, very rapidly lose their slenderness of figure and their ease of movement.

Why does the cat escape the ordinary law, and why, in spite of the fact that it rarely moves, does it seldom become fat as does a dog or horse under similar circumstances? It is because its immobility is not that of inaction, and its nerves are working while its muscles seem at rest. Like a fencer waiting the moment to attack, the cat is constantly ready to spring. It is always watching something; a rat, a fly, or a joint of meat. A drawing-room cat only makes three or four springs in the course of a day, but each of them has been preceded by two or three hours of latent work. When we believe that the animal is engaged in a happy dream, it is meditating a capture, calculating the distance of its spring, and holding its muscles in readiness for anything that may happen. Hence it is never taken by surprise. If a little bird escapes from its cage, it is caught and eaten in three seconds. The cat has been watching it for a week; when it seemed asleep, it was lying-in-wait.

CHAPTER V.

THE WORK OF CO-ORDINATION IN EXERCISE.

Difficult Exercises-Skill in Exercises-Circling the TrapezeApprenticeship of Movements-Precision in Muscular ActionsOffice of the Brain and of the Psychical Faculties in the Co-ordination of Movements-A Dancing-lesson - Muscular Education-Economy of Muscular Force and of Nervous Expenditure with equal Mechanical Work-Improvement of the Muscular Sense-St. Vitus's Dance-Hygienic Use and Importance of Difficult Exercises-Persons who should Refrain from them Error usually Committed in the Choice of an Exercise.

THE will is not the only faculty of a psychical order which is concerned in the performance of movements; its office is limited to determining the muscular action and stimulating the muscle; but other factors must come into play to regulate, direct, and measure muscular actions.

Every movement needs the intervention of a great number of muscles, and each muscle must contract with a definite force in order that the whole work may lead to a precise movement. We call work of co-ordination the operation whose object it is to choose the muscles which must participate in the movement, to regulate the respective efforts of each of them, by distributing exactly that quantity of nervous energy which is necessary to produce a contraction neither too weak nor too strong. This work is performed by the brain.

We call those exercises difficult which need rather a clever co-ordination of movements than a great quantity of work. Riding, fencing, gymnastics with apparatus,

are difficult exercises and need more skill than strength.

Seeing with what ease the most complicated actions of ordinary life are performed, we should be inclined to believe that each muscle had its function fixed in advance, and was so connected with the will, that it would be enough to wish to displace a part of the body in a certain direction, in order immediately to find the muscular group on which the duty would devolve. We forget that the most ordinary actions, those which are performed with the greatest ease, have been laboriously learned, and were at first awkward and difficult, before becoming as it were, natural and automatic, through long practice.

Difficult exercises generally need attitudes to which a man is unaccustomed, new movements which his limbs have never before practised. A new apprenticeship is necessary to learn the new muscular combinations. Certain muscular groups which have long been used to act together must be disunited in certain gymnastic movements, whilst in the same effort other groups must be united which have never before been associated. A man who tries to walk on his hands is obliged to seek attitudes which are entirely new to him, and to make in his exercise combinations of movements and balances to which his body has never before been adapted. Whatever a man's strength, he will not succeed at first. All the energy he throws into his muscular efforts cannot make up for his want of practice, for, in the case given, skill is more needed than strength.

In every new movement, in every unknown attitude needed in difficult exercises, the nerve-centres have to exercise a kind of selection of the muscles, bringing into action those which favour the movement and suppressing those which oppose it. The bones on which the muscles act must also be displaced in a direction perfectly adapted to the performance of the required action, for a

suitable inclination of these levers will favour the action, while an unsuitable one may render it impossible. Finally, all the parts in action, the limbs, the spine, or the pelvis, must execute with precision certain displacements relatively to each other whose resultant is an attitude favourable to the performance of the exercise.

When we endeavour for the first time to perform a hitherto unknown movement, it seems at first that our muscles, so docile in the ordinary actions of life, have become rebellious to the orders of the will. When the muscles finally obey, the bony levers in their turn seem to refuse to move in the desired direction, and the body, notwithstanding our most violent efforts, will not assume the attitude we wish.

There is a well-known gymnastic movement called circling the trapeze. Children who have once learned it can perform it with the greatest ease, and it needs a very slight expenditure of strength. It consists in hanging from the bar of the trapeze by the hands, and then making the legs and body pass right over the top of the bar, continuing the movement of revolution until the body has returned to its former position.

We may defy the most robust and most active man to perform this movement the first time he tries.

When he has seized the bar in his hands, the novice who attempts to imitate his teacher finds himself greatly embarrassed. He does not know how to give to his trunk the movement necessary to make his legs pass round the bar. At this moment, amidst his muscular efforts, the would-be gymnast is evidently making cerebral efforts: first he tries one muscle, then another. If he examines his own sensations he will find that he is performing work of a psychological order; his nervecentres are seeking the solution of a problem which may be thus formulated: What muscles must he contract to make his trunk change from the vertical to the horizontal position? The answer to this question is not usually found till after many trials; but it is almost a surprise when the problem is solved, and the move