376 



RESPIRATION. 



the approximation is perhaps less in the case of the exquisitely sensitive 

 respiratory centre than in many other cases. 



FIG. 103. 



VJ 



\J 



Slowing of Respiration by Stimulation of Superior Laryngeal Nerve. This curve was obtained 

 in the same way as Figs. 99, 100, 101, and the letters have the same meaning as in those figures. 

 Stimulation begins at x and ends at y. 



If in an animal in which a careful graphic record of the respiratory 

 movements is being taken, the trachea be suddenly closed at the summit of 



FIG. 104. 



B 



Effects of Distention and Collapse of Lung. (Head.) Both curves are described by a lever 

 attached, as stated in 271, to a slip of the diaphragm of a rabbit. A contraction of the diaphragm 

 (inspiration) raises the lever; during relaxation of the diaphragm the lever fails. In A, the 

 trachea is closed at x, the height of inspiration : a pause follows during which the lever gradually 

 sinks until an inspiration (a very powerful one) sets in. In B, the trachea is closed at the end of 

 expiration, x; there follow powerful inspirations. 



an inspiration, the result is a pause before the succeeding inspiration follows, 

 that is to say, a partial or temporary inhibition of inspiration ; and if during 



