38 



LOGARITHMIC ORDER OF DEATH 



tubes. This means that, of these uniform test tubes under 

 uniform conditions, one-half contains inactivated mole- 

 cules and the other does not. It is possible to compute 

 from the mass law the number of tubes in which a single 

 protein molecule is inactivated, but it must be realized 

 that the result represents only a probability and not a 

 certainty. The certainty of the mass law is founded on 

 the very large number of molecules present in ordinary 

 chemical reactions. In living cells, not all kinds of mole- 

 cules are so numerous. 



If p% of the molecules are inactivated per minute, the 

 total of a tubes will be divided into those with an in- 

 activated, and those with an unchanged molecule, as 

 follows : 



Time 



Tubes with 

 unchanged 

 ^ molecules 



Tubes with inactivated 

 molecules 



P 



a 



a 



100 

 P 



100 



P 

 100 



all 

 P II 



a 



100 

 P 



P \ P 

 100/ 100 



) 



_P_ 

 100. 



a 



V 100/ 



['-(: 



100/ 



