Before we begin the study of the Laws of Health, it is absolutely essential to know something of the human body, which is to be kept healthy.

Canon Kingsley, to whose suggestion the foundation of popular lectures of this kind is due, fully recognised this. He says, in his "Essay on Science and Health " (Health and Education, p. 13): -

"Why should not the experiment be tried, far and wide, of giving lectures on health, as supplementary to those lectures on animal physiology, which are, I am happy to say, becoming more and more common? Why should not people be taught - they are already being aught at Birmingham - something about the tissues of he body, their structure and uses, the circulation of the blood, respiration, chemical changes in the air respired, amount breathed, digestion, nature of food, absorption, secretion, structure of the nervous system, - in fact, be aught something of how their own bodies are made, and how they work? Teaching of this kind ought to, and rill, in some more civilised age and country, be held a necessary element in the school course of every child.

Just as necessary as reading, writing, and arithmetic; for it is, after all, the most necessary branch of that 'technical education' of which we hear so much just now, namely, the Texun, or art, of keeping oneself alive and well.

"But we can hardly stop there. After we have taught the condition of health, we must teach also the condition of disease, of those diseases specially which tend to lessen wholesale the health of townsfolk exposed to an artificial mode of life. Surely young men and women should be taught something of the causes of zymotic disease, and of scrofula, consumption, rickets, dipsomania, cerebral derangement, and such like. They should be shown the practical value of pure air, pure water, unadulterated food, and dry dwellings. Is there one of them, man or woman, who would not be the safer and happier, and the more useful to his or her neighbours, if they had acquired some sound notions about those questions of drainage on which their own lives, and the lives of their children, may every day depend. I say - women as well as men. I should have said women rather than men; for it is the women who have the ordering of the household, the bringing up of the children; the women who bide at home, while the men are away, it may be at the other end of the earth."

We shall first consider the human body, the parts of which it is made, and the working of those parts.

The study of the parts or organs of which an organic being such as man is made, goes by the name of Anatomy; the study of the working of those parts or organs goes by the name of Physiology. We are about to study these two subjects together for the most part throughout the first few lectures, beginning from the simplest considerations.

The rough anatomy of a human being may be described as follows: - A human being consists of a head, trunk, and extremities or limbs.

The Head consists of two parts. One is called the cranium, the other the face. In the cranium is contained an organ, and a very important organ, the brain. In the face we find, in the first place, the beginning of the organs which deal with the food, which we call the digestive organs (that beginning is the mouth, and the things that are contained in the mouth), the beginning of the organs that have to do with breathing, which we call the respiratory organs - that beginning is the nose. We find, besides these, in the face, certain organs of special sense, - the organ of taste in the mouth, the organs of sight, and the organ of smell, placed in the position in which we should expect the organ of smell to be placed, nearly at the beginning of the organs of respiration, nearly at the beginning of the tube through which air is taken into the body.

In the head we find also another pair of organs of special sense - the organs of hearing, which are situated in the walls of the cavity of the cranium.

The Trunk of human beings is roughly and ordinarily divided into two parts. The upper one is called the chest or thorax, and the lower one is called the belly or abdomen. We shall see hereafter that this is not merely a popular division, hut that it is really a rational division.

The chest contains, in the first place, the heart, and in the second, the lungs - one on each side of the chest. It also contains the great blood-vessels connected with the heart and lungs, part of the windpipe which leads to the lungs, and the continuation of a tube, the gullet or swallow, which leads from the mouth to the rest of the digestive organs. The head is connected with the chest by the neck, through which the tubes just mentioned pass, viz., the windpipe, which is connected with the lungs, and which connects the lungs with a cavity behind the month, into which the nostrils lead, and so with the nose; and the gullet or swallow, which is connected with the mouth, and passes down through the thorax into the next division of the trunk. In the lower division of the trunk, which we call the abdomen, there are contained, in the first place, the remainder of the organs of digestion, namely, the stomach, and the intestinal canal; the stomach being rather on the left hand side. On the right baud side of the abdomen is the liver. Besides these organs there is the spleen - an organ which is situated on the left hand side of the abdomen, to which the ancients attributed the property of causing anger, because they could find no other duty for it. Underneath the stomach, but situated rather behind it, is an organ we call the pancreas, which means all flesh; we eat the pancreas of the calf at table under the name of sweetbread. There are also two other important organs in the abdomen, one on each side, called the kidneys.