The locomotive moves about and does work at the bidding of the engineer. It does this just as long as it is supplied with water, and coal or wood, if the ashes, the burnt waste matters, are removed, and if its parts are kept in order.
No engineer is trusted to manage a locomotive until he understands all its parts and how they work. To avoid wrecks and loss of life, he must examine his machine at the end of every trip and see that every screw, lever and wheel is in proper order.
The human body is in many ways like the locomotive and each person is his own engineer. The body does what its owner commands as long as it is fed, if the ashes, the waste matters, are removed and if its parts are kept in a healthy condition.
No railroad company will trust the management of a locomotive to an engineer who does not know its parts, because by the neglect to repair a weak or worn part the entire engine may be ruined. For the same reason every person, who is the engineer of his own body, should know its parts.
The study of the parts of the body and their location is called anatomy. The greatest use of anatomy is to help one to understand how the parts of the body do their work.
The engineer must understand the use of each lever, wheel and screw in his engine in order to determine when they are in proper working condition. A person must likewise know the use of the various parts of his body to understand when they are doing their work properly.
One of the chief benefits to be had from the study of physiology is the knowledge which aids us much in understanding how to care for the body. By proper care all its parts may be kept in a healthy state and in most cases sickness may be prevented.
The body is a much more delicate machine than the locomotive. It is often injured by food taken at the wrong time, or in too large quantities. Impure oil and dirty coal sometimes clog parts of the locomotive and make it do poor work. Impure air and unclean food and water often seriously damage the human body so as to cause sickness and even death.
During the eighteenth century, it is estimated that 50,000,000 persons died of smallpox in Europe. To-day the disease is so uncommon that many physicians have never seen a case.
Scurvy which afflicted so many of the sailors a century or two ago now seldom occurs because the men have learned what kind of food to eat to avoid the disease. Of the French soldiers who went to fight the people of Madagascar, seven thousand died of fevers which we now know how to prevent, and only twenty-nine were killed in battle. In our war with Spain, less than three hundred of our soldiers were killed in battle, but over three thousand died of disease which hygiene has shown how to avoid.
Hygiene protects the body in time of peace as the shield and steel armor of the old Romans protected them in time of war. Health depends largely upon preventing tiny plants and animals called germs, from feeding upon our bodies, and upon supplying the body with the proper food, air, drink and clothing.
Among every thousand people there are more than twice as many deaths yearly in Russia and India as in Sweden. This is because the Russians and people of India do not observe the teachings of hygiene so carefully as the Swedes. In London, a hundred years ago, the number of deaths in every thousand residents was three times as great as in the year 1900.
In order that we may be a healthy nation, every one must observe the laws of hygiene. Each person by his own efforts alone may not be able to protect his health, for the ignorant may furnish him bad food or bad water. A milkman caused 236 cases of diphtheria in one city by being so careless as to help care.
Fig. 1. Number of acres required yearly to bury the dead among each 1,000,000 inhabitants in Germany, England and the United States. Note that the number of deaths is decreasing as people learn how to avoid disease.
1. In what way is the body like a locomotive? 2. Why should a person know much about his body? 3. What is meant by anatomy? 4. Of what use is anatomy? 5. Why should you know the use of the parts of the body? 6. What is physiology? 7. How does the study of physiology benefit one? 8. Describe what is meant by hygiene? 9. Name some diseases which long ago killed many. 10. Upon what does health depend? 11. Why do more people die in some countries than in others? 12. Why can one not protect his health by his efforts alone? 13. How can we secure the best health as a nation? for the milk when he was recovering from diphtheria. One hundred years ago, the average length of human life in the United States was 28 years. Hygiene has shown us how to prevent sickness and death so that the average length of life is now 42 years.