( 81 ) 



He says : iiolarisalioii means cliai-uiii^- a coiKlcrisalor. 



Coiise(|iieiilly il' one discliai-ges a coiidciisalor into an organic tissue 

 it is identical to discliargiiig a condcjisator witii a capacity (! into 

 another with a capacity c, and one has the ibrnnda 



C P= ('i>^r(> 



in wiiich /^ represents the number of volts with which 6' was charged 

 and /) th3 number of \'olts of the pohirisalion of the organ. For a 

 minimal contraction /i must always be constant consequently : 



cp h 



In the same manner La Picquk and others consider tiie |)olaiisation 

 of the tissues as the cause of the electric ii'ritation. 



7. Occasionally I have tried (33) to apply the formula (5) likewise to 

 other irritations than electric ones e. g. to the irritation of the retina 

 by light, to the auditory organ by sound, to the organ of touch by 

 sensation. For the latter exist very exact experiments of de Fkky 

 and Kussow (34) and the results of these could be sufficiently explained 

 from my formula (5). 



The phenomena of seeing and hearing were then deduced from 

 the formula (5) but this deduction does not satisfy me any longer. 



From the formulas found then it would follow namely that ^i should 



be extra-ordinarily great, and this is contradicted by the fact that the 



1 

 impression of light on the retina contiinies — second. This points 



8 



to a small value of /i. 



Consequently a different reasoning must be found. We no longer 



consider the influence of light as that of a tpiick alternate current 



but as a constant irritation of varying intensity, /, which we can 



express e.g. in Metercandles and we directly apply then the formula (5) : 



(ill e-/'< 



dt 



but we suppose now that the coefficient tc is dependent on the length 

 of the wave, so that the sensibility of the retina varies for light of 

 equal intensity but of different colour. The fornnda becomes then 

 for very little values of 7" 



1/ ■=! a I T 



entirely in conformity with the experiments of König and Dikterici (35). 



The same result has been found by Hla.mw (36) in his experiments 



concerning the heliotropy of plants. Here the same curvation is found 



6 



Proceedings Royal Acad. Amsterdam. Vol. XIV. 



