ENERGY SUPPLY OF THE CELL 



31 



above normal through the entire duration of the experiment which 

 was continued for fifteen more days. This meant about 5 or 6 gm.- 

 calories per hour and per Uter of soil. At this rate, about 4% of the 

 total humus would be decomposed during the first year. 



A similar method, has been applied by Bayne-Jones and Rhees 

 (1929) to study the energy production by BacL coli during the first 

 hours of growth. The cells were counted every hour, and this, 

 together with the calorimetric measurements, gives the best data 

 available for direct energy measurements. Some of the data are 

 reproduced in Table 7. 



The energy per cell, either calculated by dividing the total calories 

 produced by the average of the acting cells, or by applying the 

 formula of Buchanan (see Appendix p. 407) shows a sharp maximum 

 during the first hours, and soon drops to a low and fairly constant 

 level similar to that found by van Suchtelen (Fig. 2). Bayne- 

 Jones and Rhees believe that this is characteristic for young cells. 

 It may be, however, that the great amount of heat at the start is 

 due to an oxidation process; after a few hours, the oxygen dissolved 



in the medium will have been used up, and no more oxidation takes 

 place except on the very surface of the culture. According to 

 A. Miiller (1912), multiplying cells of Bad. coli require from 0.10 



