Section 50. the Idea of This Process of Change May Be Perhaps

rendered more vivid by giving an imaginary concrete instance of its working. In the jungles of India, which preserve a state of things which has existed for immemorial years, we find the tiger, his stripes simulating jungle reeds, his noiseless approach learnt from nature in countless millions of lessons of success and failure, his perfectly powerful claws and execution methods; and, living in the same jungle, and with him as one of the conditions of life, are small deer, alert, swift, light of build, inconspicuous of colour, sharp of hearing, keen-eyed, keen-scented-- because any downward variation from these attributes means swift and certain death. To capture the deer is a condition, of the tiger's life, to escape the tiger a condition of the deer's; and they play a great contest under these conditions, with life as the stake. The most alert deer almost always escape; the least so, perish.