Light and Colour. 77 



remarkable powers of discerning colours by touch. As this 

 can result neither from transmitted or reflected light, the 

 special kind of surface is the only thing left for detecting 

 the colour which presents itself to the touch. 



It would therefore appear, in the case of the blind, that 

 some fine impression reaches the touch from given colours, 

 or surfaces possessing those colours, which nothing else 

 imitates, and which cannot be supplied by the sun, so far 

 as we can judge. 



For if it be said that there is fine matter left on a given 

 surface by the action of the sun's rays, in those things 

 which do not transmit rays, but only reflect them, and from 

 much exposure that matter from the sun has accumulated ; 

 on the other hand, it must be said length of exposure helps 

 colours to fade considerably, and therefore material from the 

 sun accumulating is scarcely feasible. 



The view of a local surface of special ultimate forms from 

 definite chemical compounds, forming molecules of precise 

 angles and shapes, whereby certain rays are always reflected, 

 and others partially, and some, as those at direct right 

 angles, not at all, will give an insight into the reason 

 why vital manifestation in every form of differentiation 

 is accompanied by a change of colour in the organs 

 and tissues of any given product, as the leaf, through its 

 morphology, to the flower and the fruit ; and every organ 

 of the body and tissue, especially those of external manifes- 

 tation, as feathers, hair, etc., are continually presenting 

 to the eye endless varieties of colours and shades of hue, 

 but in a pretty constant form of repetition in the wild state, 

 from light, moisture, and food being, upon the whole, very 

 similar ; but under the care of man, these always suffer 

 many changes by crossing with one man's stock and another ; 

 for no two men cultivate exactly alike, or feed alike, or 

 protect from weather alike, or drain and manure alike, so 



