( 77 ) 



"Quadratwiirzel" law has entirely disappeared, at least with regard 

 to the irritation-effect of constant currents of short duration, conse- 

 quently exactly for the very case for which Nkrkst maintained it 

 was to hold best. For the minimal intensity /, recpiired for currents 

 of short duration Hill finds namely the formula : 



' = Y~^. («) 



in which ;., ft and 6f represent constants and / is (he time of irritation. 



At lirst view this formula does not correspond with mine at all, but if 



one observes that, according to Hill, (1. c. p. 20), ^ has the meaning 



of e and consequently <9' is equal to the expression e " , then 



we see that, supposing := /? the formula (8) only differs from my 



formula (7) by the occurrence of the coefficient (i, which in my 



formula = 1. Further appears from Hill's statement, that jli has a 



8 4 



value varying between —=0.84 and — = 1.27, and consequently 



rt" -t 



has an average value of 1.04, and then the difference with my formula 

 becomes so slight, that experimentally it will be utterly difficult to 

 decide which of the two formulas is the correct one. 



Keith Lucas applies in a treatise succeeding that of Hill the 

 formula (8) to a great number of experiments of himself and of 

 La Picque, demonstrates its correctness, and calculates then the 

 value of 6 or rather of log. <9 for different organs. Lucas then 

 unites in a table (1. c. p. 245) all the different values of log. 0, 

 found in this way, and sets great value upon the signification of 

 this magnitude. I am likewise fully inclined to do so, for from the 

 above follows easily that log. 6* = — i^loc/e; consequently, but for 

 one factor, log. ^ is nothing else than my coefïicient /?. 



According to my experiments (26) and in my units ^?:=1100, 

 for the motor nerves of the frog, from which follows log. & = 



— 0.47, whilst Keith Lucas (i. c. p. 246) finds from his own 

 experiments log. ^ =r — 0.33 and from those of La Picque lo(j.d^=z 



— 0.42. 



For the direct irritation of the muscles of the frog I found: 

 /3 = 88, from which follows log. 6* = 0.038, whilst Keith Lucas 

 (1. c. p. 245) gives for it figures varying between 0.027 — 0.113. 

 The accordance may consequently be regarded to be satisfactor}'. 

 At the same time it appears from the great difference of 0.027 and 

 0.113 that the errors of observation, as I pointed out more than 



