( - ^ ) 



once, with this sort of experiments, are much greater than is usually 

 supposed. 



For diflferent tissues Lucas gives in round numbers the proportion 

 of log 6 as follows: (I.e. p. 245) 



nerve-tibre 0.3 

 muscle-fibre 0.07 

 heart-muscle 0.0005 

 If one compares these numbers with the duration of the refractory 

 period (vide p. 9) it appears that tiie longer the refractory period, 

 the smaller log. 6 or ^. B'or plants that possess a very long latent 

 period, /? must consequently l)e exceedingly small. 



5. Consequently it seems possible to unite my results with those 

 of Hill and therefore also wiili the main principle of Nernst's theory. 

 But there are objections : 



a. For condensator-discharges Hill's calculations are exceedingly 

 intricate and I think it impossible to deduce from them the so 

 firmly stated formula (1). 



b. Neither is the result satisfactory for alternate currents. Though 

 it appears from Hill's fornnila that i\ ^n is not constant, as Nernst 

 pretends, the relation of the two magnitudes / and n becomes 

 exceedingly intricate. 



c. Hill has extra-ordinarily great trouble to explain the above- 

 mentioned fact of the impercei)tibly slow creeping in of strong 

 currents. Only by introducing the hypothesis that the irritation must 

 be attributed to the sudden explosive decomposition of an unknown 

 substance Hill succeeds, after a very complicated calculation, in 

 finding an explanation that can satisfy him. 



These three objections prevent me from entirely agreeing with Hill. 



The error in Hill's calculation is, in my opinion, the same that 

 I pointed out formerly in Nernst's theory, namely that the irritation- 

 process is considered in it as a single indivisible process, so that 

 irritation-effect only occurs when the change of concentration has 

 obtained a certain intensity. This would lead to the conclusion that 

 with condensator-discharges which positively cause the greatest change 

 of concentration in the beginning, also only in the beginning 

 irritation-effect could take place. 



This is an absurdity, for then the manner of discharging indicated 

 by capacity and resistance, would not have the slightest influence. 



Much more natural is, in my opinion, the hypothesis, that every 

 irritation, however slight it may be, has some effect, but that a 

 visible effect is only obtained by a summation of a great number 

 of successive slight irritations. 



