'PICTURES OF SHADOW UNDER FOLIAGE' 181 



the striping of zebras and forest antelopes, of tigers, 

 the sun-spots of fallow deer, the mottling and striping 

 of squirrels. But such a generalisation can only be 

 grasped by analysis and observation. In the field, as 

 by the sea, two types of sympathetic colouration occur. 

 One, sympathetic par excellence, reproduces the adjacent 

 background of those animals that crouch, as moths, 

 caterpillars, goat-suckers, woodcock, partridges (fig. 31). 

 The other, conventional, represents in a bolder manner 

 the more prominent features of their habitual sur- 

 roundings ; to this class belongs the tiger, the zebra, 

 and, in a special manner, the butterflies. 



The effectiveness of this animated painting in either 

 class is increased by a mode of shading from top dark 

 to under light, known to artists as effacing gradation ; 

 the white breast gives the finishing touch to this result. 



The American artist, Mr. Thayer, has pointed 

 out the significance of this gradational colouring. 

 A monochrome, especially a dull monochrome, is 

 the only revealing colouration, and we find few 

 animals (ravens and the rook family; gregarious 

 animals, as sheep, oxen, horses) of this type. If we 

 break up the mass, say by tying white ribbons around 

 a dun pony, a partial effacement is produced, and in 

 rapid movement or in moonlight the broken mass 

 melts into grey as the succession of contrasted belts 

 of colour neutralises their individual effect in crossing 

 the field of vision. 



But in a good light such strong, ungraded lines 

 increase the rotundity. The shadow deepens round the 



