THE MECHANICS OF PULMONARY RESPIRATION. 337 



FIG. 90. 



Apparatus for taking Tracings of the Movements of the Column of Air in Respiration. The 

 recording apparatus shown is the ordinary cylinder recording apparatus. The cylinder A, covered 

 with smoked paper, is by means of the friction- plate B put into revolution by the spring clock- 

 work in C, regulated by Foucault's regulator D. By means of the screw E, the cylinder can be 

 raised or lowered, and by means of the screw ^its speed may be increased or diminished. 



The tracheotomy tube t fixed in the trachea of an animal is connected by India-rubber tubing 

 a with a glass T-piece inserted into the large jar G. From the other end of the T-piece proceeds 

 a second piece of tubing b, the end of which can be either closed or partially obstructed at pleas- 

 22 



