The vocal cords usually suffer from this condition. They are thickened, roughened, and enfeebled, the delicate vibration of the cords is impaired, the clearness and purity of the vocal tones are gone, and instead the voice has become rough and husky. So well known is this result that vocalists, whose fortune is the purity and compass of their tones, are scrupulously careful not to impair these fine qualities by convivial indulgences. 357. Effect of Tobacco upon the Throat and Voice. The effect of tobacco is often specially serious upon the throat, producing a disease well known to physicians as “the smoker’s sore throat.” Still further, it produces inflammation of the larynx, and thus entails disorders of the vocal cords, involving rough voice and harsh tones. For this reason vocalists rarely allow themselves to come under the narcotic influence of tobacco smoke. It is stated that habitual smokers rarely have a normal condition of the throat. Additional Experiments. Experiment 189. _To illustrate the importance of the resonating cavity of the nose in articulation_. Pinch the nostrils, and try to pronounce slowly the words “Lincoln,” “something,” or any other words which require the sound of _m_, _ln_, or _ng_. Illustration: Fig. 154. Experiment 190. _To illustrate the passage of air through the glottis._ Take two strips of India rubber, and stretch them over the open end of a boy’s “bean-blower,” or any kind of a tube. Tie them tightly with thread, so that a chink will be left between them, as shown in Fig. 154. Force the air through such a tube by blowing hard, and if the strips are not too far apart a sound will be produced. The sound will vary in character, just as the bands are made tight or loose. Experiment 191. “A very good illustration of the action of the vocal bands in the production of the voice may be given by means of a piece of bamboo or any hollow wooden tube, and a strip of rubber, about an inch or an inch and a half wide, cut from the pure sheet rubber used by dentists. “One end of the tube is to be cut sloping in two directions, and the strip of sheet rubber is then to be wrapped round the tube, so as to leave a narrow slit terminating at the upper corners of the tube. “By blowing into the other end of the tube the edges of the rubber bands will be set in vibration, and by touching the vibrating membrane at different points so as to check its movements it may be shown that the pitch of the note emitted depends upon the length and breadth of the vibrating portion of the vocal bands.”[51]—Dr. H. P. Bowditch. Note. The limitations of a text-book on physiology for schools do not permit so full a description of the voice as the subject deserves. For additional details, the student is referred to Cohen’s _The Throat and the Voice_, a volume in the “American Health Primer Series.” Price 40 cents. Chapter XIII. Accidents and Emergencies.