THE BIOMETER: HOW TO USE IT 135 



of carbon dioxide produced by 10 mg. of the tissue 

 during ten minutes will be 



i . oX io-7 g .X = 16 . 6X 10-7 g . 



of carbon dioxide. 



In order to test the accuracy with which our new 

 method can be used for the estimation of the exceedingly 

 minute quantities of the carbon dioxide, a series of 

 determinations was made on the samples whose con- 

 centrations were unknown to the experimenters at the 

 time of analysis. 



The results are given in Table II : 



TABLE II 



One disadvantage of this apparatus III is that we 

 must take into consideration temperature and pressure 

 variation, which was entirely unnecessary for the 

 biometer proper. If the respiration and analysis are 

 carried out at different temperature and pressure, 

 the ratio between the minimum volume which gives 

 the first precipitate and the original volume of the 

 chamber will not be rigid. In that case the minimum 

 volume should be translated to the volume at the 

 temperature and pressure at the time of respiration. 

 Such correction, however, will not be necessary if the 



