But more remarkable still is the explanation given to the semblance borne by the colours of some creatures to those of others of quite a different kind, as of some moths to bees, and some harmless flies to wasps. For now it is clear that by this mimicry they escape the attacks of many enemies, who avoid such apparently dangerous forms. On the other hand, the bright liveries of such offensive creatures are highly useful to the wearers, for such tints act as a warning to enemies, and so save them from their being pounced on by creatures which might fatally wound them, though unable to swallow them. But the beautiful liveries of such powerful predatory kinds as tigers and leopards do not serve as warnings. They serve their wearers, however, none the less, though it is by aiding their concealment, and so allowing their prey to approach them unsuspectingly to fatal nearness. For the vertical stripes of the tiger resemble the vertical shadows of the grasses of the jungle amongst which it lurks, as the scattered spots of the leopard agree with the scattered spots of shadow amongst the foliage of trees on the boughs of which it lies in wait. But to say more on this head would be to anticipate remarks to come, when the relations of living beings to one another are under consideration, and the subject is too extensive to be here treated in full. Moreover, it must be noted that such relations do not by any means serve to explain all the phenomena of organic colour. Direct action is in some curious way exerted upon many organisms, by surrounding tints, and similarly different geographical districts and varieties of locality affect directly the colour of both animals and plants, but these questions will be fully treated of under the head of the relations of animals to the physical world. Suffice it here to note that the phenomena of colour no less than the phenomena of form are in harmony with (whether or not the result of) the active agencies of all environing conditions. But colour of some kind is a universal attribute of all material things. Though apparently most irregularly distributed through the world of life, yet order underlies the seeming confusion. Of certain large groups certain tints are characteristic, as has already been remarked with respect to the great order to which the dandelion belongs. But the same remark may be made of various others, as, for example, of the order _Cruciferæ_ (to which the wallflower and turnip belong), the flowers of which are generally white, pink, or yellow, while the gentians, again, are noteworthy for exhibiting pure colours.