Thus considered, we may conclude that that man alone is perfectly healthy whose body is well formed, whose teeth as well as eyes and ears are in good condition, whose nose is free from dirty matter, whose skin exudes perspiration freely and without any bad smell, whose mouth is also free from bad smells, whose hands and legs perform their duty properly, who is neither too fat nor too thin, and whose mind and senses are constantly under his control. As has already been said, it is very hard to gain such health, but it is harder [Pg 11] still to retain it, when once it has been acquired. The chief reason why we are not truly healthy is that our parents were not. An eminent writer has said that, if the parents are in perfectly good condition their children would certainly be superior to them in all respects. A perfectly healthy man has no reason to fear death; our terrible fear of death shows that we are far from being so healthy. It is, however, the clear duty of all of us to strive for perfect health. We will, therefore, proceed to consider in the following pages how such health can be attained, and how, when once attained, it can also be retained for ever. Chapter II THE HUMAN BODY The world is compounded of the five elements,—earth, water, air, fire, and ether. So too is our body. It is a sort of miniature world. Hence the body stands in need of all the elements in due proportion,—pure earth, pure water, pure fire or sunlight, pure air, and open space. When any one of these falls short of its due proportion, illness is caused in the body. The body is made up of skin and bone, as well as flesh and blood. The bones constitute the frame-work of the body; but for them we could [Pg 12] not stand erect and move about. They protect the softer parts of the body. Thus the skull gives protection to the brain, while the ribs protect the heart and the lungs. Doctors have counted 238 bones in the human body. The outside of the bones is hard, but the inside is soft and hollow. Where there is a joint between two bones, there is a coating of marrow, which may be regarded as a soft bone. The teeth, too, are to be counted among the bones. When we feel the flesh at some points, we find it to be tough and elastic. This part of the flesh is known as the muscle. It is the muscles that enable us to fold and unfold our arms, to move our jaws, and to close our eyes. It is by means of the muscles, again, that our organs of perception do their work. It is beyond the province of this book to give a detailed account of the structure of the body; nor has the present writer enough knowledge to give such an account. We will, therefore, content ourselves with just as much information as is essential for our present purpose.