AXTh'^EFTICS 



143 



The quantitative relations between the length of the lag 

 period and cell concentration, established by Ingraham 

 (p. 138) were verified by Hoffmann (see Fig. 28). This 

 is difficult to explain. If one culture were inoculated with 

 1000 times as many bacteria as the other, metabolism 

 would be 1000 times as intense and adjustment of po- 

 tential 1000 times as fast, so that the favorable poten- 

 tial should be reached in one-thousandth of the time. The 

 length of the lag period would be one-thousandth of Lagi, 

 while in reality the relation is 



Lagxooo = Lag, + k log 1/1000 

 = Lagi — 3 k, 

 k being a proportionality constant. No explanation of 

 this phenomenon has been offered. 



The antiseptic power of dyes is greatly affected by the 

 acidity of the medium (see Fig. 29). Acid dyes {e.g. 

 acid fuchsin, eosin) — which in general are rather weak 



Fig. 28. Effect of the amount of inoculum on tlie lengtli of the 

 lag phase of Bacterium coli treated with crystal violet. Abscissa: lag 

 phase; ordinate: concentration of inoculum in number of bacteria 

 per cc, on logarithmic scale. (From data of Hoffmann, 1943.) 



