1910.] Nicotine, and other Pyridine Bases upon Muscle. 345 



It is, however, rather difficult to follow the line of reasoning on which it 

 is based ; further, the numbers in the units and the tens of the derived 

 constant /a have no real significance. 



On a comparison of the constant vi of Esson's equation : — 



logKx -logKT, = »KlogTi-logTo) (1) 



with that of fi in the Arrhenius fornnila, which may be written with the 

 same terras on the left-hand side, thus : — 



logKT-logKT„ = (|^^)log. (2) 



(Kt,, Kt„ = factors of chemical change at absolute temperatures Ti, To 

 respectively), it appears that vi = fi/555, or // = 555 m. 



The values of the constants m and fi obtained by the two formula for the 

 action of the drugs : alcohol, chloroform, quinine (Veley and Waller), and 

 nicotine (A. V. Hill) are here set forth : — 



Substance. 



Temp, range. 



Values of m. 



Values of ft. 



Bafcio. 





7° to 24° 



20 -8 



11,570 



1 : 556 



Chloroform 



7° „ 24° 



14 -3 



7,700 



1 : 535 





7° „ 25° 



26 -7 



14,950 



1 : 559 





17° „ 27° 



31 -4 



17,340 



1 : 553 



The respective rates at the highest and lowest temperatures respectively 

 have been taken for the purpose of the above comparison ; a slight experi- 

 mental error in one of them would account for the rather low value found in 

 the case of chloroform. 



The range of temperature (about 20°) within which the derived constants 

 of the two formulcB are compared may at first siglit appear to be rather 

 limited ; but this equally applies in practice to most chemical changes 

 which cannot be measured as a rule with any degree of accuracy beyond a 

 limiting range of .jO". 



