THE BIOMETER: HOW TO USE IT 113 



as oxygen-free air, hydrogen, or volatile anesthetics, and 

 which are exposed to an alkaline solution in order that 

 every trace of carbon dioxide can be removed from the 

 gas in question. As stated before, for ordinary metabo- 

 lism experiments we may use but one nitrometer for 

 ordinary air only, as shown in the photograph (Fig. i). 

 Chamber A is drawn to a capillary stopcock C; chamber 



FIG. 3. Biometer. One-third actual size. The shaded portions 

 of the apparatus indicate the rubber connection, which is first coated by 

 shellac and then sealed with a special sealing wax. Some parts are 

 also sealed with mercury. 



B is drawn to a similar capillary stopcock C ', one arm 

 of which is connected to another three-way stopcock G, 

 one arm of which is connected to a mercury burette T, 

 which is used for adjusting the pressure in the apparatus. 

 (The slightly different structures should be noted here 

 in Figs, i and 3, the latter having no capillary stopcock 

 C, but being directly connected with the three-way 

 stopcock G. As the latter apparatus requires consider- 

 able experience in order to make it perfectly air-tight, 

 the former type only, as shown in the photograph, is 



