348 



PHYSIOLOGY OF BACTERIA 



compound, and that this is the cause of death. The 

 next sub-chapter (p. 361) will show that this has not 

 yet been proved. 



The reaction of one molecule of the cell constituents with n mole- 

 cules of poison does not contradict the analogy with monomolecular 

 reactions. It is assumed that the concentration of the poison mole- 

 cules remains practically constant during the reaction (see p. 341) 

 because they are in great excess over the active molecules of the cell 

 contents. 



If each cell contained only one '' reacting molecule" as the theory 

 of Rahn (see p. 284) assumes, n must be an integer, providing that the 

 cause of death is due to a compound of this molecule with the poison. 

 If several molecules of the cell must be affected in order to cause 

 death, the value of n need not be an integer (Watson, 1908). 



A very instructive study of the effect of concentration 

 of different acids was pubhshed by Paul, Birstein and 

 Reuss (1910b). The death rate of Micr. pyogenes 



