26 Art. l.-K. Fuji : 



V. Relation between the Form of Stimulus 

 and the Discharge Caused by It. 



Tlic relation belwuen the form of the electric stimulus and the 

 excitation in a nerve caused hy it, has been investigated by many 

 physiologists. Some give a formula representing the relation 

 which contains a function of an unknown form. König' s formula 

 is such an example and is expressed by 



i'=/F(/) :;;<;/, 







where E denotes the excitation evoked, and / the instantaneous 

 value of the stimulating curi'ent at a time t which is measured from 

 the commencement of the stimulating current. .Vccording to him 

 F {t) is a function of an unknown form that acts as a decrement 

 factor and that has a finite value only when t is very small. 



In 1892 Hoorweg,* in his experiments on the stimulation of a 

 condenser discharge, found a relation connecting the potential 

 difference, by which the condenser was charged, the resistance of 

 the conductor in the circuit, and the capacity of the condenser that 

 caused minimal shock in a nerve. He deduced from it a general 

 expression representing the relation betAveen the electric stinndus 

 and tlie excitation caused by it. His formula is expressed l)y 



E 



ajie-^'dt, \1) 



where « and ß are constants. According to his opiniim the element- 

 ary excitation evoked in a nerve at an instant is proportional to 

 the strength of the current l at that instant, in opposition to the 

 prevailing opinion in whicli it depended on the rate of change of the 



currents, e. ^; and as a decrement factor he introduced e~^'. Al- 

 though many authors opposed his formula, it is the only one that is 

 expressed by a definite function. He afterwards tried to deduce 



* Plumer Archiv, Bd. 52, S. 87, 1892, 



