CH. XXVI.] 



ARTIFICIAL RESPIRATION 



383 



fits of suffocation are produced by tonic spasm of the adductor 

 muscles of the glottis. Asthma is another nervous affection, and 

 has been already briefly referred to on p. 349. Whooping-cough is an 

 infectious disease, the poison of which also acts on the nervous 

 respiratory system. 



FIG. 302. This illustrates the two principal positions A and B in performing Schiifer's method 

 of artificial respiration. 



Artificial Respiration. 



In experiments on animals in which it is necessary to open the 

 chest, life can be maintained by pumping air into the lungs ; this is 

 done by means of some form of pump or bellows, the delivery tube 

 of which is connected to the trachea by a cannula, a side hole in 



