( 79 ) 



Therefore I have, like Du Bois — Reymond, made a difference 

 between the elementary irritation e, and the total irritation-effect 

 y, which is found by the formula: 



y= ( sdt (9) 



That such a summation effect exists, is generally admitted. Bikder- 

 MANN says in his Electrophysiology, page 43 "dass jedes irritabele 

 Plasma zu Summation befahigt ist." Steinach (27), who has made 

 a very exhaustive investigation on this subject, says page 339: ''die 

 Summation d. h. das Vermogen nnwirksame Einzelreize zu summieren, 

 ist eine allgemein verbreitete Lebenserscheinung." 



Steinach shows the phenomenon in nerves and muscles, in protozoa 

 and in plants. 



It is likewise irrefutable, that every irritation has an after-effect 

 on the irritated organ, which e. g. manifests itself in the so-called 

 refractory period. Formerly it was supposed that this period existed 

 only for the heart, but the latest investigations of Gotch (28) and 

 of Keith Lucas (29) have proved that it occurs with every irritable 

 organ. There is only a difference in time: for the indirect irritation 

 of muscles it lasts 0.003 sec, for the direct irritation 0.02 sec, for 

 the heart 2 sec. and for some plants 6 sec. and longer. 



As now not a single irritation is in fact momentaneous it follows 

 from the above mentioned facts that I am fully entitled to maintain 

 the formula (9). 



According to Hill (1. c p. 196) the change of concentration 

 caused by a constant current of very short duration is : 



vi Ca \ Avi 



''"+TV2 



If now according to N ernst one supposes the temporal irritation- 

 effect proportional to the change of concentration with the time then 

 we have : 



and supposing: 



dc 4vi a^ jttS 



€=ƒ- = —/ e cos- 



at a a 



4vf jr.v kn^ 



— cos — =« and := 1^ 



a a a? 



one obtains the formula: 



and from this according to (9) the formula (5) 



