( 441 ) 



the Avidlli of the sodiunilines to which my nioasiuHMiionls i-olatc 

 (winch was al)oiit 1 AiigstWuii-Uuit) (ho gTCJxtcst phase-diHereiu'c w ilh 

 wliicli iiilerroreiK'o-plioiioiiieiia can he ohyerved is one con-ospondiim 

 with 3000 wavelengtiis; the liigher liniil is therefore raised to 7000, 

 so that /• nnist in this case lie between 10 and 7000, which it 

 really does according,- to the calcidations given above. 



Some fnrther dednctions which can be made from the comparison 

 of Voiut's eqnations with those given by Diudk, have already been given 

 on pp. yc»— 95 of my doctoral thesis, with reference to Lokkntz's 

 pa[)er in the Re|>oi't of the ('oiujirs I iiti'nKit'unKil (/>' J*/ii/s/ii>ii\ hchi 

 in l*aris in 1900, and 1 will here only refer Ihe reader (o that j»ait 

 of my thesis. 



Physiology. — ".1 new hiw concernlny the reliUlon hetweeii st'mnilm 

 and elfirt." V. By Dr. J. K. A. WKirrnKi.M Salomonson. 

 (Commnnicated by Prof. C. Winklkk.) 



From the law connecting excitation and ellecl, 



£ = .1(1— f-^V^'-',) (I) 



we mav obtain bv dilferentiating 



dR 

 or also 



dE 



dR = — e^i^-C) (2) 



AB ^ ' 



Ijdroducing dilJerences instead of dilfei-entials, with lliis limitation 

 that the dilferences should be very small, and taking according to 

 Fechner, LiJ'J, the ditferential sensation-threshold as a constant (|iiaii- 

 tily, we obtain 



hR = k, iB(ii-C) (3) 



or, b}' putting the constant B—^^-k\-=k- 



LR — k^i^'i (4) 



the latter fornuda containing an expression for the absolute dilleren- 

 tial threshold- value. We might employ this formula for psychical 

 impressions of j)eri[)heral stimuli, if the peri|)heral stinndiis had caused 

 excitation of oidy perij)heral neui'ones with ecpial stimulation-c(^)nslanls 

 B, and moreover if all these neurones had been uniformly stimu- 

 lated. Under a similar limitation we nughl also adnnt the \alidity of 

 the fornuda for the relative differential lhi'eshol(i-\alue deduced from 

 (4) by dividing both terms by R; we then obtain: 



