1884.J 



Origin of the Respiratory Sounds. 



417 



the trachea to the healthy parts of the lungs, and on its way blows 

 across the mouths of the bronchial tubes leading to the consolidated 

 parts without entering them. 



There is, therefore, an d priori probability that this may be the 

 origin of some part of the sound of bronchial breathing, and in order 

 to determine whether it is so, the following experiment was tried : 



FIG. 5. 



A Y-tube of gutta-perchaj the stem about one inch and the arms 

 about half-an-inch in internal diameter, was made to represent the 

 lower part of the trachea, and its bifurcation into the two bronchi. 

 The arms were each continued by an india-rubber tube about six 

 inches long, and to the ends of the india-rubber tubes equal sized bags 

 of gutta-percha tissue were attached as represented in the figure. 

 The inside of the whole apparatus was smooth. 



The artificial thorax being filled with air, the tubes, with the bags 

 attached, were let through the roof of the chamber as far as the dotted 

 line in the figure. 



At each downward and upward stroke of the bellows air entered 

 and escaped from the bags through the tubes, as shown by the 

 direction of the arrows. The movement of the bellows was so regu- 

 lated as to completely fill and empty the bags at each stroke. 



During the inspiration and expiration thus caused, a feeble sound 

 was heard, no doubt produced at the open ends of the tubes, the 

 londness of the sounds depended upon the force with which the 



