In business and in the professions, the story is the same. The abstainer wins out over the drinking man.

Not alone in activities of life, but in the length of life, has the abstainer the advantage. Figures presented by life insurance companies show that the nondrinkers have a considerably greater chance of long life than do drinking men. So decided are these figures that several companies have lower premiums for the nondrinkers than for the drinkers who insure with them.

"Other Narcotics in Common Use. - Narcotics are very widely used by the human family for the relief which they give from pain or fatigue, or for the direct pleasurable sensations which they impart. All are deadly poisons when taken in sufficient quantities. Those most common (after alcohol) are tobacco and opium.

"It has already been shown that tobacco may affect unfavorably many parts of the system, and is especially injurious to the young. It stimulates in small quantities and narcotizes in larger ones, working its effects directly upon the nervous system. Nicotine, the powerful poison found in tobacco, affects the nerve cells, injures the brain, and leads especially to weakness of the heart by interfering with its supply of nervous force. Many cases of cancer of mouth and throat are believed to have resulted from tobacco smoking.

" Opium, for its benumbing influence upon the nerves, is used by large numbers of persons, especially in Oriental lands. Its continued use deranges all the digestive processes, disorders the brain, and weakens and degrades the character. Like alcohol, it produces an intolerable craving for itself, and the strongest minds are not proof against the deadly appetite.”

REFERENCE READING

ELEMENTARY

Sharpe, A Laboratory Manual for the Solution of Problems in Biology. American Book Company.

Davison, The Human Body and Health. American Book Company.

The Gulick Hygiene Series, Emergencies, Good Health, The Body at Work, Control of Body and Mind. Ginn and Company.

Moore, Physiology of Man and other Animals. Henry Holt and Company.
Ritchie, Human Physiology. World Book Company.

ADVANCED

Hough and Sedgwick, The Human Mechanism. references given at the end of Chapter XXIII.

HUNT. ES. BIO.-27

Ginn and Company. See also

XXIX. HEALTH AND DISEASE-A CHAPTER ON CIVIC BIOLOGY

Problem LVI. A study of personal and civic hygiene. (Laboratory Manual, Prob. LVI.)

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Health and Disease. In previous chapters we have considered the body as a machine more delicate in its organization than the best-built mechanism made by man. In a state of health this human machine is in a good condition; disease is a condition in which some part of the body is out of order, thus interfering with the smooth running of the mechanism.

Personal Hygiene. It is the purpose of the study of hygiene to show us how to live so as to keep the body in a healthy state. Hygiene not only prescribes certain laws for the care of the various parts of the body, skin, teeth, the food tube or the sense organs, but it also shows us how to avoid disease. The foundation of health later in life is laid down at the time we are in school; for that reason, if for no other, a knowledge of the laws of hygienic living are necessary for all school children. Unlike the lower animals, we can change or modify our immediate surroundings so as to make them better and more hygienic places to live in. Hygienic living in our home must go hand in hand with sanitary conditions around us. It is the purpose of this chapter to show how we do our share to coöperate with those in charge of the public health in our towns and cities.

Some Methods of Prevention of Disease. · The proverb " An ounce of prevention is worth a pound of cure" has much truth in it. Disease is largely preventable. Fresh air, the needed amount of sleep, moderate exercise, and pure food and water are essentials in hygienic living and in escape from disease.

Pure Air Needed. What do we mean by fresh air, and why do we need it? We have already seen that oxidation takes place within the body, and that air containing as little as 2 parts of respired carbon dioxide to 10,000 parts of air is bad for breathing.

In addition to the carbon dioxide, water and heat are given off as well as a very small amount of organic material of a poisonous nature. It is the presence of this material that gives rise to the odor noticeable in a close room. But other organic material is found in air. Dust from the street contains bacteria of all kinds, some of which may be disease-producing. Thus may be spread bacteria from the respiratory tracts of people who have colds, pneumonia, diphtheria, or tuberculosis. Much dust is dried

Two cultures (A) were exposed to the air of a dirty street in the crowded part of Manhattan. (B) was exposed to the air of a well-cleaned and watered street in the uptown residence portion. Which culture has the most colonies of bacteria ? How do you account for this?

excreta of animals. Soft-coal smoke does its share to add to the impurities of the air, while sewer gas and illuminating gas are frequently found in sufficient quantities to poison people. Pure air is, as can be seen, almost an impossibility in a great city.

How to get Fresh Air. As we know, green plants give off in the sunlight considerable more oxygen than they use, and they use up carbon dioxide. The air in the country is naturally purer than in the city, as smoke and bacteria are not so prevalent there, and the plants in abundance give off oxygen. In the city the night air is purer than day air, because the factories have stopped work, the dust has settled, and fewer people are on the streets. The old myth of "night air" being injurious has long since been exploded, and thousands of people of delicate health, especially

those who have weak throat or lungs, are regaining health by sleeping out of doors or with the windows wide open. The only

essential in sleeping out of doors or in a room with a low temperature is that the body be kept warm and the head be protected from strong drafts by a nightcap or hood. Proper ventilation at all times is one of the greatest factors in good health.

Change of Air.-Persons in poor health, especially those having tuberculosis, are often cured by a change of air. This is not always so much due to the composition of the air as to change of occupation, rest, and good food. Mountain air is dry, and relatively free from dust and bacteria, and often helps a person having tuberculosis. Air at the seaside is beneficial for some forms of disease, especially hay fever and bone tuberculosis. Many sanitariums have been established for this latter disease near the ocean, and thousands of lives are being annually saved in this way.

The Relation of Pure Food and Pure Water to Health. Thanks to the care of state and city governments there is little need nowadays for the health of any individual to suffer from impure food or water. But that people do become sick and die from such causes every day is well known, as is shown by the many cases of typhoid fever, summer complaint, and ptomaine poisoning of various sorts. Our milk may have been watered or sent in cans washed with water containing typhoid germs, we may eat oysters bred in contaminated localities, we may have received and eaten fruits or

Our laws,

Not only

vegetables sprinkled with water containing the germs. however good, cannot cope with human carelessness. should we as individuals demand from the source of supply pure food and water, but we should do our share at home to keep them

pure. Flies and other insects should be prevented from reaching food. Vegetables and fruits must not be eaten in an unripe or half-rotted condition, nor should the latter be canned or preserved. All raw fruits or vegetables that are not protected by the skin should be washed before eating. In general, foods may be made safe to eat by cooking long enough to kill the germs. Milk to be rendered absolutely safe should be pasteurized (so called after Louis Pasteur, the inventor of the process), that is, treated to 160° Fahrenheit for 20 minutes. Ptomaine poisoning is often caused by the growth of bacteria in canned material. These bacteria were not all killed by the cooking, grew, and gave off the poison or ptomaines. Such foods are dangerous, for cooking does not destroy the poison. Meats which have been hung so long as to have an odor, and cold storage meats that appear to be decayed, should be avoided.

Relation of Proper Exercise and Sufficient Sleep to Health. We are all aware that exercise in moderation has a beneficial effect upon the human organism. The pale face, drooping shoulders, and narrow chest of the boy or girl who takes no regular exercise is too well known. Exercise, besides giving direct use of the muscles, increases the work of the heart and lungs, causing deeper breathing and giving the heart muscles increased work; it liberates heat and carbon dioxide from the tissues where the work is taking place, thus increasing the respiration of the tissues themselves, and aids mechanically in the removal of wastes from tissues. It is well known that exercise, when taken some little time after eating, has a very beneficial effect upon digestion. Exercise and games, especially if a change of occupation, are of immense importance to the nervous system as a means of rest. The increasing number of playgrounds in this country is due to this acknowledged need of exercise, especially for growing children.

Proper exercise should be moderate and varied. Walking in itself is a valuable means of exercising certain muscles, so is bicycling, but neither is ideal as the only form to be used. Vary your exercise so as to bring different muscles into play, take exercise that will allow free breathing out of doors if possible, and the natural fatigue which follows will lead us to take the rest and sleep that every normal body requires.