ENERGY SUPPLY OF THE CELL 



95 



exactly to the buffers observed and used extensively in 

 working with hydrogen ion concentrations. In reduc- 

 tion potentials it is spoken of usually as the ''poising" 

 effect. 



The first example for such buffering or poising is 

 probably that by Gillespie (1920) who measured the 

 reduction potentials of various waterlogged soils. The 



Fig. 9. — Reduction potential of raw milk with two different indicators. 



results of the daily measurements for the calomel electrode 

 as zero are shown graphically in Fig. 8. While the last 

 three soils show a potential greatly differing from that 

 of the calomel electrode, with a strong reducing intensity 

 on the second day, the first, soil remained much less 

 reducing for four days, and on the fifth day was still 

 less reducing than any of the others on the second day. 

 Repeated experiments proved this to be a constant 

 character of this one soil which is evidently well poised. 



