During ordinary health, some part of every day ought to be spent out of doors; and in ill-health it is of great importance not to discontinue the observance of this rule without good reason; for, although in certain states of disease it may be very important to remain in-doors, it must not be forgotten that proper clothing, goloshes, respirators, and umbrellas, may make it not only safe but advantageous to go out of doors for exercise, when, without them, it would be very injurious. (See Posture, and p. 187 of the Author's work "On Winter Cough," 3rd edit.)

Out-of-door exercise should be as active as the strength will allow, and should always be continued up to the point of slight - but not over - fatigue. This will be the best measure of the proper amount for both the weak and the strong.

Unless the air is pure, and the person strong, exercise before breakfast is more likely to do harm than good; a tumbler of milk and a biscuit, however, will be a sufficient meal to take before the walk or ride - a more substantial breakfast being taken afterwards. (See Meals.)

Especial care is needed not to expose the body to chills when heated by exercise (See Clothing); and cold drinks should not be taken at that time, unless the exercise is about to be continued immediately; and even then the quantity of cold drink taken at once should be very small. (See Meals.)

In his work "On Physical Education," already referred to, Mr. Maclaren makes the following excellent remarks:

"Such in brief is Exercise, such the ends which it accomplishes, and such the manner of their accomplishment; viz., the destruction of the tissues, the hastening of the decay and death of every part coming within its influence; but also the speedy removal of all waste, the hastening forward of fresh material for its replacement; and in doing this it attains three distinct but co-relative results."

1. It increases the size and power of the voluntary muscles employed.

2. It increases the functional capacity of the involuntary muscles employed.

3. It promotes the health and strength of the whole body, by increasing respiration and quickening circulation. .........

It is health rather than strength that is the great requirement of modern men at modern occupations; it is not the power to travel great distances, carry great burdens, lift great weights, or overcome great material obstructions; it is simply that condition of body and that amount of vital capacity, which will enable each man, in his place, to pursue his calling and work on in his working life with the greatest amount of comfort to himself and usefulness to his fellow men..... Let it not be inferred from this that I consider health and strength as in any manner opposed to each other; on the contrary, they are most intimately allied, and are, usually, by the same means and by the same manner obtained; very closely are they connected, but they are not the same, and a man may possess either without the other......A most important principle in Exercise, and one which should ever be borne in mind, is that it should be regulated by individual fitness; for the exercise that scarcely amounts to exertion in one person will be injurious and dangerous to another; and not only is this inequality observable among different individuals, but the same individual may have parts of his body possessing special power or presenting special weakness. A man may have limbs capable of transporting him at the rate of four miles an hour throughout the day, and for many days in succession, but with heart or lungs all unequal to the effort; or he may have an organisation so frail and a temperament so susceptible to stimulation or excitement, that the one is an abiding danger to the other." (See the author's work "On the Mont Dore Cure" etc., 1st ed., p. 2.)

When there is no heart or lung disease to interfere, there is no form of gymnastic exercise, so generally efficient as "skipping backwards."