SENSATION. 101 



dispute the probability, which indeed amounts almost to a 

 certainty, that as civilization advances and the fine arts 

 become developed, the colour-sense undergoes a progressive 

 improvement in its power of distinguishing between fine 

 shades, and also in its power of ministering to a more and 

 more evolved condition of a?stlietic feeling. And this, I 

 believe, is the true explanation of the class of facts alluded to 

 by Professor Hseckel as proof of the speculation which I have 

 now discarded — the fact, namely, that '' nowadays we see in 

 the surviving savage races a crudity as to their sense of 

 colour .... Our little ones, also, like the savages, 

 love assemblages of glaring hues which grate upon us, and 

 susceptibility to the liarmony of delicate shades of colour is 

 the latest product of aesthetic education." 



Professor Preyer has published within the last year or two 

 a very interesting theory touching the origin and development 

 of the colour sense, and as it has not, to my knowledge, been 

 noticed in any English publication, I shall here state the main 

 points. The theory is that the colour-sense is a special and 

 highly-exalted development of the sense of temperature. To 

 sustain this theory, Professor Preyer first compares the sensi- 

 bility of the skin to temperature with that of the retina to 

 light, and points out that the analogy has already been 

 recognized by artists, who speak of colours as " warm " and 

 " cold." " The warm colours arouse sensations of a character 

 antagonistic to those which are aroused by the cold colours, 

 in just the same way as the hot and cold sensations of skin- 

 temperature are antagonistic ; and the more this analogy is 

 pursued, the closer is the agreement found to be.'' Therefore ^/ 

 the suggestion arises, " that the sense of colour has been , 

 developed out of the sense of temperature," bespeaking a 

 high refinement of functional activity which has its struc- 

 tural correlative in the extremely differentiated and delicately 

 organized expansion of nerve-endings which we find in the 

 retina. 



A further analogy is that of contrasts. A finger that has 

 been warmed or cooled retains its change of temperature for 

 some time after it has ceased to be warmed or cooled ; and 

 this is taken to correspond with the phenomena of positive 

 after-images in sensations of colour. Moreover, while the 

 after-efi'ect of warming or cooling a portion of the skin 

 remains, the temperature-sense of that portion is altered in 



