482 



SCIENTIFIC THOUGHT. 



13. 



Miiller's 



"specific 



energies." 



the peripheral stimuli of the senses inward to the 

 nervous centres (sensory or afferent nerves). 



About the same time Johannes Miiller, under the 

 influence of Goethe's observations on the subjective 

 colour -sensations and of Kant's doctrine of the innate 

 forms of perception, 1 introduced another important dis- 

 tinction into the theory of the action of the sensory 

 nervous apparatus. This doctrine is known by the 

 name of the " specific energies." It has for a long time 

 governed all physiological reasoning on the subject of 

 our sense perceptions. In the words of Helmholtz, who 

 more than any other has lent the great weight of his 

 authority to an elucidation of this theory, " physiological 

 experience has found that by the stimulus of any single 

 sensible nerve -fibre, only such sensations can be pro- 



1 The doctrine of the " specific 

 energies " of the sensory nerves, one 

 of Joh. Miiller's earliest speculations, 

 which has governed a large section 

 of psycho - physical research, at 

 least in Germany, has grown out of 

 the philosophical discussions in the 

 ' Kritik der reinen Vernunft,' and 

 the aesthetic treatment in Goethe's 

 ' Farbenlehre,' both of which deal 

 with the subjective element in our 

 sense-perceptions. In this regard 

 the reform of physiology in Germany 

 contrasts with the contemporaneous 

 reform by Magendie in France, 

 whose extreme experimentalism 

 Miiller even ridiculed. See on the 

 historical origin of Miiller's psycho- 

 physics, Du Bois-Reymond's excel- 

 lent "Eloge of Muller " ('Eeden,' vol. 

 ii. p. 159), also Helinholtz's lecture on 

 " Goethe's Naturwissenschaftliche 

 Arbeiten" ('Vortriige und Reden,' 

 vol. i. No. 1, 1853), and his address 

 before the Goethe Society in 1892. 

 Helmholtz finds the cause which 



misled Goethe in his optical experi- 

 ments to be the same which misled 

 Brewster viz., the difficulty of ob- 

 taining really pure homogeneous 

 light of any special tint. He worked 

 with impure light and dull media. 

 Helmholtz experienced great diffi- 

 culties in obtaining the neces- 

 sary purity in his own labours. 

 Goethe, however, was not alone in 

 studying with predilection the sub- 

 jective colour-sensations. Du Bois- 

 Reymond mentions Erasmus and 

 Robert \V. Darwin in England, and 

 Purkinje in Germany, as working 

 in the same field (loc. cit., p. 160). 

 Miiller's work is contained princip- 

 ally in the treatise, ' Zur vergleich- 

 enden Physiologie des Gesicht- 

 sinnes des Menschen und der Thiere 

 nebst einem Versuche iiber die 

 Bewegungen der Augen und iiber 

 den rnenschlichen Blick' (1826), and 

 in his larger work on Physiology. 

 See also on Goethe's merits Helm- 

 holtz, ' Physiologische Optik,' p. 249. 



