MECHANISM OF DEATH 393 



to allow of the computation of a death rate. This order 

 becomes the more evident the more nearly the bacteria 

 are of uniform age and resistance. The computation 

 of this death rate, as such, does not involve any definite 

 conception concerning the mechanism of the reaction. 

 The utilization of death rates is not different in principle 

 from the utilization of the times required to kill all bac- 

 teria of a given suspension, and makes no more assump- 

 tions. It is more accurate, and more likely to guard 

 the investigator against errors since there are several 

 points to be considered and coordinated, instead only 

 the one datum, i.e., the killing time. If the death rate 

 is not approximately constant, it cannot be used for 

 drawing conclusions. 



The fundamental reaction, i.e., the reaction in the 

 cell which causes death, is known only in very few 

 instances. The death of dry bacteria is known to be an 

 oxidation process. Death by heat is probably due to 

 the coagulation (or hydrolysis) of a certain compound 

 in the cell. Good progress has been made in the search 

 for the fundamental reactions in chemical poisoning. 

 It would seem possible that most of the causes of death 

 will ultimately be shown to result in the same chemical 

 process, or in the reaction upon the same molecules, 

 but if that should be the case, we are far from having 

 proved it. 



Of the enormous number of experiments on chemical 

 disinfection, an extremely small fraction only is fit to 

 throw light on the underlying causes of death. On 

 account of the importance of the subject, an enormous 

 number of new experiments is to be expected, and it is 

 hoped that the technique of these future experiments 

 will live up to the standards set by Kronig and Paul more 

 than thirty years ago. 



