22 
are cases in which we cannot reconcile the blotches 
found in plants with any thing like symmetrical 
arrangement; but these are exceptions, not the rule; 
are probably caused by the colours, dependent upon 
veins, being accidentally blended ; and upon the whole 
it is safer to assume in all cases that varieties of colour 
have really some fixed relation to the veins of the 
parts in which they occur than to regard them as vague 
and accidental. So that, notwithstanding Mr. llus- 
kin’s great authority, I think his statement is not 
borne out by what we know of plants. 
