206 RESPIRATION, BLOOD, AND EXCRETION 



of the arteries to become smaller. For this reason it is 

 called a stimulant." —Conn and Buddington. 



It has been stated frequently that alcohol increases the 

 activity of the heart. Careful experiment, however, 

 shows that not only is the effect not that of a stimulant, 

 hut that when used in large amounts, it markedly weakens 

 the action of the heart. If taken only in small amounts, 

 the heart sometimes shows a slight increase in its rate of 

 beating, but this occurs only when the brain becomes ex- 

 cited, and if the person is kept quiet no change in the 

 heart beat is noticeable. Thus the primary action is on 

 the brain. 



" A second effect of alcohol is more evident. The small 

 blood vessels in the skin are enlarged. This produces a 

 flushed skin, a feeling of warmth, and a false feeling of 

 increased circulation. Its result is to send more blood 

 through the skin with consequent extra loss of heat. This 

 action is evidently not due to stimulation, but to the re- 

 laxation of the muscles, and is thus a decrease of activity 

 rather than an increase, even though the blood does flow 

 a little more rapidly through the skin. These facts make 

 it clear that alcohol cannot be properly called a stimulant 

 of the circulatory system." — Conn and Buddington. 



160. Excretion. — Every animal uses energy in carrying 

 on its work. During this process a certain amount of 

 waste substance is produced, which has to be removed 

 from the body. The skin, kidneys, and lungs are the 

 chief organs which assist the body in getting rid of this 

 waste. When any part of the living cells is broken down 

 in the simple act of living, a waste product results. By 

 osmosis these waste products enter the blood and are 

 removed by the lungs, which give off carbon dioxide; by 

 the sweat glands in the skin; and by the kidneys, which 

 remove the wastes that contain nitrogen. The sweat 



