MECHANISM OF DEATH 



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it appears to be much more a question of chance which 

 cells survive. 



{i) SUMMARY OF FACTS 



Dying is a gradual chemical change in the cell, and 

 any definition of death is the arbitrary assumption of 

 one point on a time curve. 



If we define a dead cell as one which has lost the 

 power of reproduction, the death of bacteria through 

 heat, chemicals, light, drying and some other causes 

 proves to be an orderly process. If the logarithms of 

 survivors are plotted against time, bacteria show either 

 a straight line or a curve sagging below a straight line, 

 while larger organisms give a curve which bulges out 

 above the straight line. In only three cases, bacteria 

 are known to show consistently bulging curves. 



A ^' death rate" can be computed by using the formula 

 for the rate of reaction in monomolecular processes. 



