Health is generally considered to be freedom from disease. However, health also involves the state of the mind. If you are satisfied with life, if your mind functions accurately, and if you possess enough force, driving power, and impetus to give you confidence in yourself and the ability to accomplish your work, you have good mental health.

Happiness has been described as a balanced flow of energy and the satisfaction of desires. You are happy if you get what you want. Many people do not know what they want. People differ in the things they want. Everyone who is ordinarily healthful is interested in getting enough to eat and enough rest, and in satisfying the ordinary desire for reproduction.

The mosquito is proof of Kipling’s famous statement that “the female of the species is more deadly than the male.” The male mosquito does not bite. The female mosquito is out for blood. The mosquito does not really bite, but saws through the skin.

There are three broad surgical applications where existing tissue adhesives have won a firm place. The first is where bonds are required in tissues which are so delicate that conventional stitching is either impossible or extremely time consuming. Brain surgery is one example where it is impossible to stitch thread in an organ which has a consistency (when alive) like soft peanut butter. Surgical glue, usually applied as drops rather than as a spray, is often used toward the end of a brain operation to seal regions that have become exposed or weakened by the surgeon’s scalpel.

Another area where surgical glue has already found a place is in combination with conventional stitching. This approach is now common in plastic surgery where tissue adhesive, usually applied as a spray, can leave much less of a scar than stitches.

On Vietnam’s battlefields, doctors were faced with massive numbers of casualties -many with horrifyingly severe internal wounds and in imminent danger of bleeding to death. The task of the surgeon was to treat each casualty effectively but quickly in order to move on to the next patient. A new kind of wound dressing was needed to speed up the surgical procedures accordingly. Tissue adhesive or surgical glue, applied by spraying, proved highly valuable in dealing with serious hemorrhaging under pressure of time.

The idea of a quick-acting tissue adhesive has been a surgeon’s dream for many years. For instance, when operating to repair the liver of a soldier wounded by shrapnel, massive bleeding must be brought under control within minutes—but, the delicate tissue of the liver requires painstaking stitching that demands hours of concentrated work. A quicker answer lies in a spray can.

All sorts of insects attack and prey upon human beings. Most common of those that attack the body directly are the lice and the itch mites. Less frequent are bedbugs and spiders. In the woods and in tropical areas chiggers and mosquitoes, ticks and the biting flies annoy mankind.

CHIGGERS

With the coming of modern air conditioning, there is more and more tendency toward proper ventilation. The average home, however, can easily be ventilated by opening the windows occasionally and allowing a brisk circulation of air through the rooms. Indeed the ordinary home as now built contains enough chinks, cracks, and space under doors and windows to permit a good deal of fresh air to circulate constantly.

Mechanical systems of air conditioning have value in crowded places, like factories, workrooms, motion-picture theaters, and public halls. Frequently such systems constitute the only means by which a sufficient amount of good pure air can be secured. Unfortunately most air-conditioning apparatus is operated without any recognition of the functioning of the human body. The human body adapts itself to a good many extraordinary conditions. Sudden changes in temperature from cold to warm or from warm to cold place considerable stress on the physiology of the human body.

Once it was thought that only the chemical constituents of the air were important in distinguishing good air from bad air. More recently it has been recognized that the physical qualities of the air are also important. Dusts and pollens may be primarily responsible for symptoms like those of hay fever and asthma from which many people suffer.

When a room contains a great many people without arrangements for free ventilation they begin to feel drowsy and fatigued. This sensation results from a combination of the warmth and the accumulation of a certain amount of dioxide which is exhaled in the air from the lungs.

The human being is sensitive to the atmosphere in which he lives. Air is the most necessary of all substances needed for life. A human being can live about forty days without food, about four days without water, but only about four minutes without air. Air is a mixture containing approximately 21 per cent oxygen, 78 per cent nitrogen, and a fraction of 1 per cent of a number of other gases. The air of our large cities is contaminated by the gases that come from the bodies of man and from industry, by dust and germs of various kinds, and even by droplets of fluid.

After the food leaves the stomach, it is acted on by several digestive enzymes. Some of these are secreted by glands located, like the stomach glands, in the wall of the intestine. But the most powerful digestive juices of all are those secreted by the pancreas and poured into the intestine in its upper part. One of the pancreatic enzymes, trypsin, is a rapid and powerful split-ter of the protein foods.

Another, lipase, splits fats into simpler absorbable compounds. The third, amylase, resembles the salivary secretion, ptyalin, in that it breaks down complex starches and sugars into simpler chemical forms. The pancreatic secretion mixes with the food, as has been said, at the upper part of the small intestine.