THE FRONTIERS OF MEDICINE 



of the heart condition by the methods that have been 

 mentioned. He does not hesitate to insert a needle and to 

 withdraw the fluid. 



The beat of the heart was first heard by an investigator 

 who placed his ear directly on the chest. Then came the 

 discovery of the method of listening to the heart through 

 a solid rod. Later more delicate devices were discovered 

 which had a bell for collecting the sound, a membrane 

 for amplifying it, and rubber tubes to carry the tone of 

 the sound to the ear. With the development of electric 

 translation of sound and new means of amplification, it 

 now becomes possible to step up the sound so that tiny 

 variations may be determined. 



Through examination after death from a known disease, 

 it is possible to correlate all the observations made before 

 death with the actual appearance of the heart and to learn 

 the significance of each of the procedures used in diagnosis. 

 Of special interest to the patient as well as to the doctor 

 is the question of how capable the heart may be of carrying 

 on its work. To the specialist in heart disease a dozen 

 or more functional tests are known whereby he can measure 

 the capacity of the organ to withstand unusual effort. 



Heart disease is, to-day, the most frequent cause of 

 death, its rate being at least twice that of the next nearest 

 cause. Hence, the number of men giving special attention 

 to diseases of the heart is increasing by the old law of 

 supply and demand; though there are as yet few, if any, 

 physicians who devote themselves exclusively to this 

 branch. Diseases of the heart is a special department of 

 internal medicine. 



It is known to the specialist in heart disease that this 

 organ may become inefficient and degenerate for many 

 reasons. For instance, the acute infectious diseases may 

 leave a weakened heart in their wake; and infections of 

 the throat and of the teeth may be transferred to the valves 



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