OXYGEN DETERMINATION 



1ST 



sumption of oxygen is given, then the distance between 

 the consecutive descending lines will be increased; while 

 a drug which increases the relative consumption of oxy- 



To suction apparatus 



-Large glass tube or Liebig condenser 

 with graduated scale (c.c.) 



Removable pinchcocks 

 ' Inspiratory\ 



4-1, ;. * 



To trachea 

 of animal 



Glass tube 



Large 

 glass 

 jar or 

 dish 



/Inspiratory 

 valve 



Fig. 178. Dreser's arrangement of apparatus for recording the volume of air ex- 

 pired by an animal in a given length of time. The large glass tube (or Liebig con- 

 denser jacket; is filled with water which is supported up in the tube by the pressure 

 of the atmosphere. The by-pass is closed and the clip on the tube leading from the 

 milk bottle inspiratory valve is removed. When the animal inspires, air enters the in- 

 spiratory tube, bubbles through the water in the bottom of the bottle and thence passes 

 to the lungs. At expiration the air passes through the straight course of the tubes to 

 the large glass jar or dish and thence is liberated in the lower end of the large glass 

 tube. The exhaled air then quickly displaces the water and rises to the upper part of 

 the large glass tube where it can be measured on the scale. 



