THE SIONSES 427 



Pitch and Range of the Voice. — The pitch of the voire depends upon 

 the length of the vocal cords and, hence, on the size of tin; larynx, lor this 

 reason, a boy's voice changes from a high to a lower pitch during the period 

 of rapid growth. The range of voice is about three octaves. This means a 

 difference in the vibration of the vocal cords from eighty-eight times jier 

 second, in a low note, to nearly eight hundred, in the highest note. The 

 range and actual pitch of the voice is controlled by the muscl(?s of the larynx 

 attached to the sides of the voice box. When the tension of the cords is 

 increased by stretching them, a higher tone results from the tighter stretch- 

 ing of the cord. 



Speech. — Articulation or speech is caused by the interruption, for a 

 very short period of time, of the air current as it passes over the vocal ror<ls 

 or as air passes between the almost closed lips. Vowels are really musical 

 tones produced in the larynx. Semivowels, especially the n, m, and ng 

 sounds, are produced by a tone which emanates from the voice box, but 

 with the soft palate lowered. The air current is forced out, partly through 

 the nose. The resonance of air in the nose cavity gives them a characteristic 

 sound. Consonants are produced in part by the action of the tongue in 

 connection with different positions of the lips while the air is forced out of 

 the mouth. Practice before a mirror, and observe the shape assumed by 

 the lips when you make the following sounds: p, t, g, s, j, ch. Record the 

 movement in each case. 



'' Alcohol and Tobacco as affecting the Vocal Organs. — As 

 the perfect control of the voice depends upon the healtliy condi- 

 tion of all the muscles connected with the vocal apparatus, and 

 upon the accurate adjustment of nervous force to their varying 

 needs, anything which affects those muscles or the nerves affects 

 also the voice. Alcohol and tobacco do affect both. The mucous 

 membrane of the larynx is often much inflamed by tobacco smok- 

 ing, and especially by the use of cigarettes. The inflammation 

 may extend through the Eustachian tubes, impairing the hearing, 

 and into the bronchial tubes, causing an annoying couixh. A 

 disease known as ' smoker's sore throat ' may result. Alcoholic 

 beverages irritate the throat and are often forbiilden to those 

 cultivating the voice for singing.'' — Macy, Physiology. 



Reference Books 



Some valuable suggestions for laboratory work in human physiolofO' may be 

 obtained from Eddy, Experimental Physiology and Anatomy, .Vnifrican li<x)k Com- 

 pany, and Peabody, Laboratory Exercises in Anatomy and Phyniologxj, Honry Holt 

 and Company. Of the briefer texts the best are Eddy, Text-book of Physiology, 



