PHYSICAL FORCES INVOLVED IN BIOLOGICAL ACTIVITIES 165 



Then the total E. M. F. of the chain can be calculated as follows: 



307.0 _ x 500.2 = N.E. N.E.= normal element. 



1000 Ac.' 1000 Ac. Ac. = accumulator. 

 _ 307.0 _Ac. , , x = the chain. 



1000 1000 = scale on bridge. 



500.2 _ N.E. 

 1000 Ac. 



1000 N.E. 

 Ac. = 



500.2 



1000 X 1.0189 , , 



~^oT~ 



Substituting (2) in (i), 



_ 37- \/ I000 X 1-0189 

 x /\ 



1000 500.2 



= 0.6254 volt, which is expressed p. 



Substituting the value for p in the formula, 



0.525-0.3377 



EH 



0.0577 + 0.0002 (19.2 18) 



= 4.967 



or in terms of H ion concentration, 



PH = 4-967 = - 4-967( 1 g- H) 

 IO -4-967 = 1>07 g 9 x IO -5 



H = 0.000010789 



Besides the apparatus listed below, a H-generator was employed, 

 which is a good-sized Kipp's generator used with a series of washing 

 bottles and drying tube, consisting of (a) 30 per cent. KOH, (b) alkaline 

 pyrogallic acid, (c) cone . H 2 SO 4 and soda lime in U-tube. Since a consid- 

 erable amount of CO 2 is produced during the course of metabolism, the 

 same precaution is taken as with blood. For this purpose Hasselbach's 

 electrode with shaking arrangement is employed. 



In setting up the apparatus special attention should be paid to 

 rigidness, insulation and temperature. In order to meet with these 

 requisites the apparatus was placed on a big central table in the labora- 

 tory. First, one dozen large glass rings of the same height were 



