This suggests another obvious remark. When we speak of the struggle for existence, the popular view seems to construe this into the theory that the world is a mere cockpit, in which one race carries on an interminable struggle with the other. If the wolves are turned in with the sheep, the first result will be that all the sheep will become mutton, and the last that there will be one big wolf with all the others inside him. But this is contrary to the essence of the doctrine. Every race depends, we all hold, upon its environment, and the environment includes all the other races. If some, therefore, are in conflict, others are mutually necessary. If the wolf ate all the sheep, and the sheep ate all the grass, the result would be the extirpation of all the sheep and all the wolves, as well as all the grass. The struggle necessarily implies reciprocal dependence in a countless variety of ways. There is not only a conflict, but a system of tacit alliances. One species is necessary to the existence of others, though the multiplication of some implies also the dying out of particular rivals. The conflict implies no cruelty, as I have said, and the alliance no goodwill. The wolf neither loves the sheep (except as mutton) nor hates him; but he depends upon him as absolutely as if he were aware of the fact. The sheep is one of the wolf's necessaries of life. When we speak of the struggle for existence we mean, of course, that there is at any given period a certain equilibrium between all the existing species; it changes, though it changes so slowly that the process is imperceptible and difficult to realise even to the scientific imagination. The survival of any species involves the disappearance of rivals no more than the preservation of allies. The struggle, therefore, is so far from internecine that it necessarily involves co-operation. It cannot even be said that it necessarily implies suffering. People, indeed, speak as though the extinction of a race involved suffering in the same way as the slaughter of an individual. It is plain that this is not a necessary, though it may sometimes be the actual result. A corporation may be suppressed without injury to its members. Every individual will die before long, struggle or no struggle. If the rate of reproduction fails to keep up with the rate of extinction, the species must diminish. But this might happen without any increase of suffering. If the boys in a district discovered how to take birds' eggs, they might soon extirpate a species; but it does not follow that the birds would individually suffer. Perhaps they would feel themselves relieved from a disagreeable responsibility. The process by which a species is improved, the dying out of the least fit, implies no more suffering than we know to exist independently of any doctrine as to a struggle. When we use anthropomorphic language, we may speak of "self-assertion". But "self-assertion," minus the