THE HEART l6/ 



is natural, and grows larger to accommodate itself to the 

 strain. Repeated calls to extra exertion may cause it to 

 respond more quickly and with more vigor than occasion 

 demands, so that a slight excitement or exertion causes 

 palpitation. Those who engage in races are especially 

 liable to overwork their hearts. 



291. Palpitation of the heart. The response of the heart 

 to influences from the outside may be excessive, so that it beats too 

 quickly and more forcibly than occasion demands. Sudden noises, 

 and excitement of any kind, cause the heart to beat violently or palpi- 

 tate in some persons. But palpitation of the heart is an annoyance 

 rather than a disease. While the will has no control over the heart, 

 yet it can control the emotions which cause the palpitations. Persons 

 of calm temperament, who exercise self-control over their emotions, are 

 rarely troubled with palpitation. Our words ending in "hearted," as 

 " warm-hearted," are records of the old belief that the heart governed 

 the feelings instead of the feelings affecting the heart. 



292. Fatty heart. The heart may become diseased, 

 but heart disease is by no means so dangerous as is com- 

 monly supposed. In fact, those having diseased hearts 

 are usually unaware of it for years, while, on the other 

 hand, those who think their hearts are diseased are almost 

 always mistaken. 



There is a common change of the heart's muscle, in which little 

 particles of the muscle cells are changed to fat. The cells are thus weak 

 ened, and made unable to respond to a sudden extra demand. A per 

 son with excessive development of fat elsewhere, is liable to have a 

 fatty heart. Avoidance of things which tend to cause excitement and 

 overwork will enable such a heart to work on without noticeable change 

 in its actions. 



293. Disease of the valves of the heart. The other 

 common form of heart trouble is a thickening and puck- 

 ering of the valves, causing a leakage so that some blood 

 flows backward. But the heart grows larger and stronger, 



