MECHANISM OF DEATH 387 



SUMMARY OF THEORIES 



Death by starvation does not show the logarithmic 

 order of death. The survivor curve bulges above the 

 straight line. 



In balanced salt solutions, the death rate by starva- 

 tion is independent of the salt concentration, within 

 fairly wide limits. 



The death of yeast cells on a protein-free diet shows 

 the typical bulging starvation curve. The death rate 

 is not proportional to the rate of loss of nitrogen from the 

 cells. 



The cause of death by starvation may be either an 

 oxidation or a hydrolysis of some cell compound which 

 cannot be counteracted by the cell if food is lacking. 

 With Bad. coli, oxidation seems to be the main cause, 

 while with Bad. typhosum^ oxidation is certainly not 

 the main cause. 



The temperature coefficient of death by starvation 

 is not known accurately. All experiments have such an 

 evident effect of cold-shock at the lower temperature 

 that the true rate of death by starvation at low tempera- 

 tures is not known. All such temperature coefficients 

 mentioned in literature are very probably too low. 



XII. DEATH BY SUFFOCATION 



Suffocation shall be defined here as death by the 

 absence of oxygen. All animals die ultimately in the 

 absence of oxygen, though some lower animals, like 

 the intestinal parasites, can live for a considerable period 

 without it, and thrive better at a low oxygen tension. 



With bacteria, death from this cause is not so well 

 known. Some experiments by Whipple and Mayer 

 (1906) show that Bad. typhosum in tap water dies more 



