MECHANISM OF PROCESS OF DEATH 75 



desirable to carry out determinations as far as possible 

 at a standard temperature, preferably at 18° C. 



In conclusion, attention may be drawn to the effects of 

 temperature*® upon consecutive reactions such, as are here 

 assumed to be responsible for the phenomena with which 

 we are dealing. The temperature coeflScient of death in 

 NaCl 0.52 M, and CaClg 0.278 M is not far from 2. 



The temperature coefficients of life processes have 

 within the last few years attracted a good deal of atten- 

 tion. Interest has chiefly centred about the question 

 whether life processes have the temperature coefficients 

 of ordinary chemical reactions and whether investiga- 

 tions of this sort enable us to distinguish between 

 chemical and physical processes (on the ground that 

 in general, the latter possess lower temperature coeffi- 

 cients than the former). 



In these discussions of life processes it is generally 

 assumed that we are dealing with simple chemical reac- 

 tions. A little consideration shows that this cannot always 

 (or even commonly) be the case. Most substances formed 

 in the organism are also broken down, and the amount 

 present must depend on the relative rates of formation 

 and of decomposition. Change of temperature may affect 

 consecutive reactions in an entirely different manner from 

 simple reactions (in which the substance formed is not 

 at once broken down). This may be made clear by a 

 concrete illustration. 



Let us take for this purpose the death curve in NaCl 

 (Curve I, Table III) and consider the effect of raising the 

 temperature 10° C. If both reactions have the tempera- 

 ture coefficient 2, K^ becomes 0.036 and K2 becomes 1.080. 



" Cf. Osterhout (1917, E). For the temperature CQeflBcients of living 

 and dead tissues in sea water see p. 37. 



