SYSTEMATIC SYNTHESIS OF ORGANS INTO APP. 389 



not draft over a person, and the skin is properly clad. It is only in the 

 case of infants, the aged, or the sick, when heat enough cannot be pro- 

 duced in the lungs to equal that which cold aic would take from them, 

 that they cannot with safety be allowed to receive cold air. It should 

 then be warmed, but always pure. Nothing can be worse than impure 

 air. Its influence is illustrated by drowning. (See Ap. 0.) 



Vocal Apparatus. 



1267. THAT THE AIR EXPELLED FROM THE LUNGS 

 MAY BE AUDIBLE, it must be thrown into vibrations, and 

 for this purpose must issue in a rapid, impulsive current. 



1268. VIBRATION CAN ONLY BE PRODUCED by consid- 

 erable pressure upon the air emitted, to effect which the 

 air-passages must be closed hastily, and suddenly opened. 



1269. BY RAISING THE WINDPIPE, closing it, and at 

 the same time compressing the chest, the air in the lungs 

 is forced upward against the epiglottis, the raising of 

 which, or the dropping of the windpipe, will allow the 

 air to gush out with a forcible current ; one process. 



FIG. 250. 1270. THE SEC- 



OND PROCESS CON- 

 SISTS in throwing 

 the jet of air into 

 vibrations, which 

 is accomplished in 

 the larynx. 



1271. THE LAR- 

 YNX IS CONSTRUCT- 

 ED of framework, 

 muscles, nerves, 

 and a lining of 

 blood-tubes. 



1272. THE 



FRAMEWORK IS 

 CONSTRUCTED of 



1267. What necessary ? 1268. How can - ? 1269. What done ? 1270. In 

 what does ? 1271. How is ? 1272. How is V 



