This section is from the book "Health", by W. H. Coefield.
In youth, the third period, growth is still going on : a great deal more food is required then than later on in life, and much exercise is desirable. It is not necessary to warn great numbers of the youths of this country that exercise is necessary, for sometimes it would appear to be almost worshipped, but there are great masses of people in this country who do not take a right amount of exercise. Girls, as a rule, do not take anything like as much as they ought; it has become very much more prevalent in girls' schools to make them take more exercise, and it is a very good thing; but there are numbers of young people who are engaged many hours a day, not at work which requires much bodily exercise, but at work which is called sedentary work, sitting in offices and work-rooms, and they do not feel much inclined for exercise when the day's work is over, and very often, in the time that they might devote to exercise, do many other things which are not by any means advantageous to them. It ought to be impressed upon them that they are people who, at their time of life, require bodily exercise,-I mean bodily exerrise in which all their muscles are more or less brought into play. Walking to and from their business is all very well in its way, but it by no means exercises all the muscles of the body. There are plenty of exercises that can be got at a very little cost. Foremost are regular gymnastic exercises : by the regular practice of these all the muscles of the body are exerted in turn, and they have a great advantage in that a very short time is sufficient for them every day. Gymnastic exercises are not always or often performed in the open air,-that is one of their disadvantages,-but they are generally performed in well-ventilated rooms, which is the next best thing.
Another exercise which should be resorted to by a great many more than it is in the summer is swimming -an exercise by which almost all the muscles of the body are brought into play, and which is also beneficial from the point of view of cleanliness. And here I ought to say that youth is the time when habits of life are formed, and it is especially important that they should be formed in the right way ; it is a time when such a habit as that of cleanliness, by which the action of the skin is promoted, should be formed, and when habits of attention to the action of the excretory organs of the body should be inculcated ; because if the waste substances are not separated from the body as they are formed they will be re-absorbed into the blood, and will poison it; that poisoned blood will be distributed to the various tissues of the body, and I believe that we have no idea how many of the diseases of middle and old age are due to the neglect of the proper action of the excretory organs.
After exercise there should be no fatigue felt for any length of time; if fatigue is felt for a long period after, it is a sign that either the exercise has been too violent or too prolonged ; and that makes me remark that it is extremely important that exercise should not be taken too violently. It is necessary that there should be plenty; and, later on, much more violent and prolonged exercise can be taken with impunity than could have been taken during the period of growth.
Another habit that is sometimes formed during this period of youth is the habit of drinking alcoholic liquors. Now, whatever we may think, whether we agree with those who say that alcoholic liquors are injurious, or whether we are of opinion with Dr. Parkes, that we are not in a position to say that alcoholic liquors are altogether injurious, we must agree with the statement that the drinking of alcoholic liquors is extremely pernicious to young people-there are no two opinions upon that point; and, perhaps, a still more important thing is, that habits of this nature are very easily contracted, but very difficult to get rid of later on in life.
While I am discussing habits, I may mention smoking-a habit that, in this country at any rate, is, practically speaking, confined to one sex. Now, whatever we may think with regard to smoking, whether we think it altogether injurious, or whether we agree with a large number of people who think that, later in life, after the fatigues of a day's mental and physical work, the soothing of a pipe or a cigar is a very pleasant and agreeable thing, and, on the whole advantageous, there are not two sides to the question when applied to growing people. Everybody agrees who has studied the subject at all, that for growing boys smoking is an unmixed evil, and that fact cannot be too widely known.
Consumption is the most fatal of all diseases during youth. I told you before that it is the plague of our climate, and it is especially so at this period of life. It is then it exerts the utmost fatal influence, and it is especially prevalent among young people who have to work either in trades where there is much dust in the air, or who have to work in close over-crowded rooms, where they breathe air over and over again. The trades in which consumption is especially prevalent are those in which there is much dust in the air, it does not matter what kind of dust; and there can be no doubt that a great deal of consumption among work-people would be prevented if they would take the precaution of wearing something to prevent the dust being drawn into the lungs. Several admirable things have been designed, and one of them has been designed by Professor Tyndall-a respirator, containing cotton-wool, which is capable of filtering off from the air that people breathe the dust that it contains, and there can be no manner of doubt whatever that if work-people could be induced to wear this, or something like it, they would be prevented, in many instances, from becoming consumptive. Many work-people are only persuaded with the greatest difficulty to use anything that prevents their trade from being a dangerous and therefore a lucrative one ; and a most notable example of this is the extreme difficulty there was in introducing the Davy safety-lamp.