GROWTH 



193 



period of growth at a constant rate is therefore sometimes 

 given the strange name ^^ period of logarithmic growth"; 

 the bacteria really increase exponentially and not 

 logarithmically. 



It is a common observation that the rate of multiplica- 

 tion of a culture is not uniform throughout the entire 

 period of development. A decrease in the rate towards 



Fig. 17. — Logarithmic growth curves of Bacterium A at different temperatures. 



the end would be expected, but there is also a period of 

 slow development at the start, during the first hours 

 after inoculation. This "Isig period" is visible in the 

 curves of Fig. 17 and is especially conspicuous in the high 

 generation times during the first hours of development 

 in Table 48. 



The ''lag period" has been the cause of much investiga- 

 tion. As early as 1895, Max MuUer explained it through 



