Our Bodies 337 



never use alcoholic drinks show the greater power of endurance. 

 It would seem, then, that alcohol, even in small doses, diminishes 

 both the quantity and quality of muscular work. 



Experiments made by experts in regard to the effect of alcohol 

 on the single cell have shown that it is injurious. Bearing in mind 

 that all muscles are composed of minute cells, and that the effect 

 of the continued use of alcoholic drink, even in moderate amount, 

 is cumulative, there can be no other logical conclusion than that 

 alcoholic drink is detrimental to the work of muscular tissue. 



SUMMARY 



The functions of the human body and of all living organisms 

 are sensation, motion, respiration, food-taking, digestion, absorp- 

 tion, circulation, assimilation, excretion and reproduction. 



Individuals relate themselves to the outside world by means 

 of the organs of sense and of motion. The organs of motion 

 are the muscles. The movements of the bones and of all the parts 

 of the body are controlled by muscles, of which there are over 

 five hundred in the body. 



Muscles are classed as voluntary or involuntary, according as 

 they are or are not controlled by the will. They are also classed 

 as flexor and extensor according to whether they bend or straighten 

 a limb. Most muscles are arranged in pairs and are joined to the 

 bones by tendons. 



As muscles work and need constant repair, they require a 

 constant supply of food and air, regular exercise, and rest to keep 

 them in good working condition. 



Physical culture is systematic exercise of the muscular system. 



Experiments have shown that the effect of alcoholic drink on 

 muscular tissue and muscular activity is to reduce efficiency. 



FACT AND THOUGHT QUESTIONS 



1. Name the important parts of the general structure of the body and 

 state what organs control them. 



2. How do individuals relate themselves to the outside world? 



3. How is your body different in function from an engine? 



4. Describe the structure of a voluntary muscle. 



