When people who have previously neglected exercise start to take it, they are often met with one difficulty. They complain that after they have walked for a mile or so they are too tired to go any farther, and when they return home they do not feel refreshed but rather the opposite. Under these circumstances we need not hesitate to assure them that if they will but persevere, this feeling of fatigue will pass off, and a sense of enjoyment and lightness take its place. Once they have experienced the truth of this they are ready to continue the daily walk and exercises, and soon begin to wonder how they ever managed to live without them. This acute fatigue is due to the stirring up of the waste matter in the system. If, however, they force themselves to keep on walking quietly, the exercise itself will help to eliminate these undesirable elements, and so fulfil its most important function. This question of exercise calls for special mention in the case of women of the middle and upper classes. Too often their exercise for the day consists in shopping or paying calls, neither of which are conducive to health. The constantly recurring headaches from which many women of this type suffer might be cured, along with the observance of the other rules of health, by the observance of a daily walk and gentle exercises within their own homes. [Sidenote: Indoor exercise.] Indoor exercise is the department in which so many people go wrong. A young man is convinced of the necessity of keeping himself fit, and the way in which as a rule he sets about it is to practise with a pair of heavy dumb-bells before breakfast, or else to buy a developer and use it, for the purpose of getting his muscles up. Now Mr. Sandow himself has always been the first to warn people against the abuse or over-use of the developer, and against practising with heavy dumb-bells. I was once amazed to hear that great authority say that he could keep his muscles in perfect condition with two-pound dumb-bells. Little wonder, therefore, that men of ordinary physique find themselves, after a quarter of an hour with seven-pound ones, stale and tired for the remainder of the day. We have to bear in mind that the most important muscle in the body is the heart. Cases are not uncommon in which young fellows have developed their limb-muscles at the expense of this vital organ, with the result that they have been more or less incapacitated ever afterwards. It may be very delightful to possess a biceps twice as large as your neighbour’s, but beyond the gratification of contracting it for their approval there is nothing to be gained, unless you are going to be a navvy, that is to say. And that is not likely to be the case with any of my readers, for navvies are not in the habit of perusing books on health. They do not need to do so.