412 Mr. J. F. Bullar. 



In Determine the [Nov. 



As neither of the above theories is universally accepted, the experi- 

 ments about to be described were undertaken in the hope of deter- 

 mining in what parts of the respiratory tract the breathing sounds 

 are produced, and of deciding which, if any, of the above-mentioned 

 theories is the true one. 



The experiments were, for the most part, performed with the 

 artificial thorax rcpi-esented in fig. 2. This consisted of an air-tight 



Fio. "2. 



chamber A, with glass sides fixed upon a firm wooden bench. From 

 the chamber A, a large smooth hole passed through the bench into a 

 secondary chamber C, the sides of which were made of flexible 

 india-rubber cloth, like a bellows. The upper edge of the india-rnbber 

 was fastened air-tight to the lower surface of the bench round the 

 hole leading into the chamber A. The bottom of the bellows B was 

 attached to the handle D, moving on a hinge at E. At the bottom 

 of the bellows was the tap F. 



Near the middle of the roof of the chamber was a hole H large 

 enough to admit a sheep's or calf's lung when collapsed. A tap I 

 jind the tube of the flexible stethoscope L also passed through the 

 roof, the inner end of the stethoscope being covered with bladder to 

 prevent the escape of air or water throngh it. 



