With regard to the increase in the number of times each exercise is done, it is quite impossible to lay down any general rule, since anyone whose muscles are already accustomed to rapid movement will be able to increase the exercise more quickly than one who is not; but as a general guide for everyone it may be said that none of the exercises should be repeated more than once or twice after the least feeling of fatigue or aching begins. But far more important than mere repetition is the rapidity of movement with which one does those that are meant to be rapid, and it is infinitely better to do such exercises only half the number of times suggested, with concentration and speed, than twice the number if they are done slackly or not fully. The first essentials are to do them correctly and rapidly; the endurance and strength to repeat them many times with correctness and rapidity will come of their own accord. But the correctness is also a _sine quâ non_: for it is the intelligent and faithful obedience of the body to the will which is no less an object of exercise than the efficiency of the body considered by itself, and just as to practise these exercises correctly is the foundation of a good habit, so to practise them incorrectly is the foundation of a bad one. For athletes, then, we believe that they will help in a marked degree to keep the muscles in good tone when there is forced on them a period of inaction from games. This effect would not be obtainable from dumb-bell exercises, since the latter for the most part are slow movements which are not of the least good as practice for games, but (though undoubtedly strength-giving) if used alone rather prejudicial to speed than otherwise. And for non-athletic people and athletes alike, they will help to keep the body in good health, not only because, for reasons given above, exercise is healthy, but because many of them are specially devoted to using those large muscle-areas of the body on which the proper daily working of the system depends, and these are exercised without risk of straining, whereas to exercise them with heavy dumb-bells in the hands has before now produced, and will again produce, injury. Furthermore, the body is far less liable to be attacked by definite disease if it is in a healthy condition, while also the daily hardening which it will experience in the system of exposure which we recommend, will render it considerably less prone to catch cold by reason of draughts or change of temperatures, which otherwise are often the immediate causes of chill.