THE RESPIRATION APPARATUS. 



II 



shelf of the table, are used for the analysis of the residual air in the 

 chamber. 



These various features of the apparatus are described in more detail 

 beyond. The above description is simply to afford a general idea of the 

 laboratory and apparatus as a whole before the more specific explanation 

 is undertaken. 



THE RESPIRATION APPARATUS. 

 GENERAL PRINCIPLE. 



The respiration apparatus in its present modified form is constructed 

 on the " closed-circuit " plan. It consists of a chamber large enough 

 for the subject a man to live in comfortably, and ventilated'by a cur- 

 rent of air which is kept in circulation by a rotary blower. Provision 

 is made for purifying the ventilating current of air, which is, after puri- 

 fication, returned to the chamber. The general scheme of the apparatus 

 is shown diagrammatically in figure 6. 



RESPIRATION 

 used 

 H 3 



CHAMBER 



^-,o i 



nt rpducsd 



FlG. 6. Diagram of Circulation of Air through Respiration Apparatus. 



In the upper portion of the figure the respiration chamber is shown, 

 and below it the blower and absorbing or purifying system. Air from 

 the chamber, containing nitrogen, carbon dioxide, water vapor, and a 

 somewhat diminished percentage of oxygen, passes through the blower 

 and enters the absorbing system. Here it is forced through sulphuric 

 acid to remove the water vapor, and through a specially prepared soda 

 lime, which takes out the carbon dioxide. The soda lime, however, 

 contains water, more or less of which is taken up by the air current. 



