CH. l] RESPIRATION. 7 



introduced into the flask absorbs the C0 2 produced. A 

 second sample of the gas may however be used if it is 

 taken within a few minutes of the first. When the test- 

 tube i is omitted the flask can be shaken before analysis 

 so as to insure that there is no accumulation of CO 2 at 

 the bottom. 



The analysis is made in the following manner: A 

 strong KHO solution (1 in 2) is introduced into B (flg. 4) 



v-t 



1 



O s =! 



Fig. 3. Exp. 4. 



Fig. 4. Exp. 4. 



until its level reaches A, and then by blowing down B 

 the KHO is forced up the fine tube E and into a thick- 

 walled india-rubber tube connected with it. As soon as 

 the solution appears at the open end of the tube, the 

 clamp G is closed. The tubes G and F (fig. 5) of the 

 measuring burette are then a little over half filled with 



