PHYSIOLOGICAL ANATOMY OF THE RESPIRATORY ORGANS. 117 



fered with. This is particularly marked in yonng animals, in which the walls of the 

 larynx are comparatively yielding, when the operation is frequently followed by immedi- 

 ate death from suffocation. The movements of the glottis enable us to understand how 

 foreign bodies of considerable size are sometimes accidentally introduced into the air- 

 passages. The respiratory movements of the larynx are entirely distinct from those con- 

 cerned in the production of the voice and are simply for the purpose of facilitating the 

 entrance of air in respiration. 



Attached to the anterior portion of the larynx, is the epiglottis, a little, leaf-shaped 

 lamella of fibro-cartilage, which, during ordinary respiration, projects upward and lies 

 against the posterior portion of the tongue. During the act of deglutition, respiration is 

 momentarily interrupted, and the air-passages are protected by the tongue, which presses 

 backward, carrying the epiglottis before it and completely closing the opening of the 



12 



FIG. 35. Trachea and bronchial tubes. (Sappey.) 



1, 2, larynx; 3,3, trachea; 4, bifurcation of the trachea; 5, right bronchus; 6, left bronchus; 7, bronchial division to 

 the upper lobe of the right lung; 8, division to the middle lobe: 9, division to the lower lobe ; 10. division to 

 the upper lobe of the left lung; 11, division to the lower lobe; 12, 12, 12, 12, ultimate ramifications of the 

 bronchi; 13, 13, 13, 13, lungs, represented in contour; 14, 14, summit of the lungs; 15, 15, base of the lungs. 



larynx. Physiologists have questioned whether the epiglottis be necessary to the com- 

 plete protection of the air-passages ; and, repeating the experiments of Magendie, it has 

 been frequently removed from the lower animals without apparently interfering with the 

 proper deglutition of solids or liquids. We have been satisfied, from actual experiment, 

 that a dog will swallow liquids and solids immediately after the ablation of the epiglottis, 

 without allowing any to pass into the trachea ; but it becomes a question whether this 

 experiment can be absolutely applied to the human subject. In a case of loss of the 



