SELIG HECHT 681 



stant at the dijfferent temperatures. Computation of equation (9) 

 using the various values of t, ki, and z yields the quantities plotted 

 in Fig. 4, and given in Table II. 



We are now in possession of the means of estimating the relation 

 between the temperature and the speed of the inactivating reaction 

 T -^ N. If our reasoning has been correct, these velocity constants 

 should be related to one another according to the Arrhenius equation 

 (3) previously given. Fig. 4 shows this to be true. The points are 

 the logarithms of the velocity constants k-z, whereas the curve gives 

 the theoretical expectation according to equation (3) solved for 

 log ^2 as follows: 



log ki = log k'2 + 



2.303 



R yr T" y J 



(10) 



In making the computations, T' is put at 296° ( = 23.0°C.) and ki 

 is the value of ^2 at this temperature as given in Fig. 4. The factor 



— — — converts natural into common logarithms. For drawing the 

 2.303 



curve in Fig. 4, /x is equal to 48,500. A much better agreement 

 between observed points and the theoretical curve is hardly to be 

 expected under the circumstances. 



The fact that the hypothetical inactivation reaction, T ^ N , 

 shows a constant value of ix brings increased confidence in the reasons 

 for its assumption. More convincing, however, is the order of 

 magnitude oi n. In the table collected by Arrhenius (1915, p. 54) 

 it is shown that ordinary chemical reactions such as saponificatrons 

 and hydrolyses possess values of ai between 10,000 and 20,000. This 

 agrees well with our findings of ^u = 19,680 for the fundamental 

 reaction of the latent period, L —^ T. However, the chemical re- 

 actions involved in spontaneous destructions and in heat coagulations 

 have values of ix which are rarely below 30,000, and are usually well 

 above this figure. For the destruction of trypsin, /x = 62,000; for 

 the heat coagulation of hemoglobin, ix = 60,100; for the inactivation 

 of emulsion, ^x = 45,000; etc. It is therefore highly significant that 

 the reaction T -^ N, postulated for the heat inactivation of the 

 thermolabile substance T, shows a value oi ix = 48,500, thoroughly 

 in accord with those usually found for such processes. 



