APPENDIX 407 



Computing from this equation the fermenting capacity 



X 



per hour by substituting s = - we get 



^ ^ X't' 0.434(& - g) log 2 

 log 2 (log b — log a) 



or 



S • (log b - log g) 

 0.434 . ^ • (6 - g) 



For the short period A^, with the increase in products 

 AaS, we obtain 



^ 2.301 ' AS ' (log g - log b) 

 ^ At'ia -b) 



This formula has been applied in this book wherever 

 the fermenting capacity per cell has been computed. 

 It holds fairly true as long as the bacteria multiply 

 rapidly. After the curve has passed the point of inflex- 

 ion, however, the products increase no more according 

 to geometrical progression. At this stage, the computa- 

 tion of the fermenting capacity is more accurate if the 

 increase in products is simply divided by the arithmetical 

 average of the number of cells at the beginning and the 

 end of the period. This corresponds to the principle 

 demonstrated in Fig. 42. 



Table 133 shows some computations by the two meth- 

 ods, and it is evident that the difference is not great. 



In this table, the initial values obtained for the fermenting capacity 

 are far too high. This is due to the great probable error in the 

 determination of the extremely small amounts of acid formed. For 

 instance, if we assume for culture II that at nine hours, not 0.007 %, 

 but 0.002 % of acid had been formed, the fermenting capacity would 

 have been for the period from six to nine hours 9.1 and for the period 



