Xii CONTENTS 



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(c) Reduction potential indicators 92 



(d) Buffering or poising the system 94 



(e) Factors involved in reduction 96 



(/) Summary 101 



V. The Rate op Fermentation 102 



(a) Methods of measuring the rate 102 



(b) Rate of fermentation of different organisms 104 



(c) Decrease of the rate of fermentation 107 



(d) Influence of the concentration of microorganisms . . .114 



(e) Influence of the concentration of the substrate . . . .114 



(/) Influence of temperature 119 



(g) Chemical stimulation and inhibition 137 



VI. The Endpoint op Fermentation 140 



(a) Chemical considerations 140 



(6) Constancy of the endpoint 146 



(c) Influence of the concentration of cells 146 



(d) Influence of temperature 151 



VII. Changes in Type op Fermentation 155 



(a) Changes due to the chemical composition of the medium 155 



(6) Changes due to temperature 156 



(c) Influence of concentration of substrate 157 



(d) Selection of foods 158 



(e) Summary 160 



PART C. GROWTH 



I. General Considerations 162 



(a) Measurement of growth 162 



(&) Building materials of the cell 163 



(c) Sources of carbon 164 



(d) Sources of nitrogen 168 



(e) Sources of oxygen 172 



if) Waste products of construction 173 



(g) Balance sheets of feeding experiments 175 



II. Relations between Growth and Fermentation .... 180 



(a) Efficiency of utilization of energy 180 



(6) Efficiency of young and old cells 183 



(c) Summary 188 



III. The Growth rate 189 



(a) Methods of measuring the growth rate 189 



(b) The lag period 192 



(c) The decreasing growth rate 199 



