74 THE HUMAN BODY. 



3. Alcohol has the power to change muscle gradually 

 into fat. The heart is particularly liable to this change. 

 As the fibers soften down, it loses its strength. It can 

 not do the work of pumping the blood through the body 

 with its natural vigor. The body, therefore, suffers in 

 every part. Such a fatty, soft heart is liable to break 

 suddenly. 



4. As old age comes on, the walls of the arteries fre- 

 quently become changed in previously healthy persons. 

 They get fatty and soft, or chalky and brittle, in spots. 

 In this state they easily burst, if by excitement, or over- 

 eating, or some other cause, they are unusually full. This 

 is especially liable to occur in the blood-vessels of the 

 head. The blood pours out; and, as the skull is a tight 

 box, the brain is pressed so hard that it can not act. 

 The person so affected becomes 'unconscious, and is very 

 likely to die. This takes place suddenly, and it is called 

 apoplexy. 



5. Apoplexy is a disease of advanced life. These 

 changes do not take place in the arteries of the young 

 without special causes. Alcohol is such a cause. It 

 makes the young man old before his time, and liable to 

 sudden death by the rupture of an artery in the brain. 



QUESTIONS. 



SECTION I. 1. In what way is the blood held in the body ? 



2, Why are the heart and blood-vessels called organs of circula- 

 tion? 



3, What are the three kinds of blood-vessels ? 



4, Describe the capillaries. 



SECTION II. 1, What is the heart? 



