Man possesses many great truths that he is slow to reduce to practice, and very strangely no small proportion of them bear on his physical welfare. He wishes to be well and dreads to be sick, yet for some unaccountable reason he insists upon indulging his inclination in violation of what he knows to be right, and scarcely any subject is more unwelcome to him than that of organic law which he holds so lightly.

Exercise

Among his many shortcomings but few are more pronounced than failure to give due attention to muscular exercise. He recognizes that it is beneficial, and theoretically he is in favor of it, but of enthusiasm, as a rule he is surprisingly destitute. His notions of the good it does are also decidedly hazy, and when pressed to define them he usually indulges in vague generalities, among which appear opening the pores, getting up a muscle, brightening the spirits, etc. Usually, also, he is content with his indifferent knowledge of the subject, and his methods of applying what little he has are quite as erratic and incomprehensive as his definition.

Underrating the value of exercise to himself he is far from likely to form a correct estimate of its importance in animal life unless it is literally forced upon him, and especially reluctant is he to accept the truth when conviction means some sacrifice of his convenience, as it generally does where dogs are involved.

Considering all this, the writer feels it his duty to discuss at considerable length the specific effects of exercise, the evils of too close confinement and the means by which dogs may be held in check and yet suffer much less injury than is generally inflicted by restraint.

Glancing at the physiology of exercise there first appears the fact that a very large part of the body consists of muscular tissue, in which is contained nearly one-quarter of the blood, and by it fully one-fourth of the nerve energy stored up in the body is turned into work. This tissue is made up of single muscles, the number of which in the dog is not accurately known, but as there are over five hundred in the human body it is fair to assume that this number is not very greatly in excess of that in all the higher order of animals. Every muscle has blood-vessels and nerves, and fresh blood is supplied its substance by the heart through its arteries and the fine network of small vessels formed by a minute subdivision of them. These small vessels open into and are continuous with veins of about the same size, and they in turn are united into larger and larger vessels that finally connect with the channels by which the blood is returned to the heart.

Once a muscle begins working the blood stream passing through it becomes swollen and presents decided changes in quality. The blood which enters is bright red in color, rich in oxygen and poor in carbonic acid, while that which leaves it is dark blue in color and of a higher temperature; it has parted with much of its oxygen and has taken up a large quantity of carbonic acid, also various products from chemical changes that have occurred in the food materials supplied the muscle by the blood, and in the muscle itself. Obviously this is the condition demanded for the integrity of a muscle, for it is now receiving a full supply of fresh blood and there is free and rapid drainage of all its noxious waste matters. Go a little further and by means of proper food in sufficient quantity and an abundance of pure air render the blood rich in nutritive elements and oxygen, also allow the muscle due intervals of rest, and it must be not only healthy but increase in size and weight.

As exercise acts on a single muscle so it acts on the muscular system as a whole - it enlarges and strengthens it. But the muscles themselves are not the only parts of the body that are benefited by exercise, for brought into action by it they in turn increase the rapidity of the flow of blood to the heart. This vital organ also works more vigorously and a larger quantity of blood is sent through the lungs; while the breathing is quickened and more oxygen absorbed. The fires within are now brightened up, and in consequence the skin and other organs of secretion and excretion are brought into action to get rid of the excess of heat and the clinkers and ashes, as it were, the products of combustion. Thus exercise acts as a spur and brings every important organ in the body into more active play.

Now, deprive the body of sufficient exercise and note the result. The digestive organs are among the first to show signs of distress and decline in power, and their work is but sluggishly and imperfectly performed; the food constituents taken up from them by the blood are not properly oxidized; drainage of noxious products is not only impeded in the muscles but in all the organs which constitute the body's sewerage system, and in consequence this waste accumulates to still further lower vitality through its poisonous action. The digestive organs once weakened are soon seriously disordered, and all the time the whole system is sympathizing with them and suffering like derangement; the nerves are unstrung; all the various functions are impaired; the muscles become soft and flabby or fat;. good health has gone and disease is imminent.

These are some of the evil consequences of a denial of sufficient exercise; but there are yet others, and by no means the least serious of them is the peculiar tendency on the part of the victims to accumulate too much fat, which is not alone deposited under the skin and in the muscles of the body, but in and around the heart and other vital organs. No one needs to be told that meat which is lean is tough while that which is fat is tender; all may not know, however, that the difference is due not only to the presence of the fat but to its degenerating influence upon the muscle fibres. The heart - which is a muscle - and all other muscles are weakened as they are encroached upon by fat, and even if the same is merely deposited around them it mechanically interferes with their workings. Too fat dogs, like corpulent men, have generally fatty hearts; moreover, they are "short-winded," easily tired by exertion and singularly inclined to be constantly ailing.