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POPULAR SCIENCE MONTHLY. 



In this way the vocal cords may be seen in any stage of their vibra- 

 tions, and the instrument may also be so adjusted that one series of 

 vibrations is omitted, and the second step of the vibration is taken 

 up, so that we apparently have a slow motion of the vocal cords, which 

 enables us to study their action during voice production. This has 

 given us much useful information, especially regarding the subject of 

 the various registers of the human voice. 



Having now explained the production of the voice under normal con- 

 ditions, I must now show how this is affected by abnormal conditions, 

 and also point out some suggestions as to the care of this important 

 organ. You will remember that the vibrations of the vocal cords pro- 

 duce the fundamental elements of the voice. Any condition which 

 prevents their free vibration will therefore interfere with the normal 

 voice. The most frequent disturbances are due to 'colds' in which the 

 vocal cords may become congested or inflamed. This produces a thick- 

 ening of the vocal cords which lowers their rate of vibration, and, con- 

 sequently, lowers the tone and gives rise to the hoarse voice charac- 

 teristic of an ordinary cold. When this condition, from any cause, 

 becomes chronic so that instead of a simple swelling of the vocal cords 

 we have a chronic thickening, it may leave, unless corrected, a perma- 

 nent defect in the voice. 



A more serious influence on the voice is due to growths or tumors 



either on the vocal cords or in some other 

 part of the throat, and interfering with 

 the formation of vocal sounds. In the 

 adjoining illustration, the small tumor 

 shown between the vocal cords had 

 caused hoarseness by interfering with the 

 vibrations of the vocal cords, and by irri- 

 tating the throat had set up a persistent 

 cough. About eighteen months before be- 

 ing seen, the patient had leaped into the 

 Mississippi Eiver to save a child from 

 drowning. The exposure was followed 

 by a severe cold, leaving a persistent hoarseness, afterwards accom- 

 panied by a cough. About a year and a half afterwards, the patient 

 was sent to me and a careful examination revealed this small tumor 

 on the vocal cord, which affected his speech, so that it was of an ex- 

 tremely husky character. The following day this tumor was removed 

 by means of an instrument passed from the mouth into the throat, the 

 course of the operation being followed by means of a mirror as already 

 explained, and being rendered painless by the application of cocaine, 

 and the tumor removed. The voice being freed from the dampening 



Fig. 10. Small Tumor of Vocal 

 coei) interfering with voice pro- 

 DUCTION. 



