For example, a country is well supplied with water and it is as a consequence fertile and “green.” In such a country green insects and green reptiles will be selected, because a green background will render them almost invisible to their enemies. Individuals of other colors will make their appearance by variation, but they will be such plain targets to their enemies, they will be devoured before they reach breeding age and have a chance to reproduce the variation. But suppose desiccation (drying up) sets in. The country loses its water supply, as Krapotkin has shown to have been the case in North-West Mongolia and East Turkestan, leading to the enforced exodus of the barbarians. Now green will disappear and brown or yellow--say brown--takes its place. While this change will not, so far as we know, cause insects and lizards to breed brown instead of green, it will ensure the survival or “selection” of such as are born brown and the destruction of those who breed true to their green ancestors. Now every atavistic return to green will be mercilessly weeded out, just as, when the country was well-watered and green, every sporadic production of brown was done to death. This is the biological foundation of that environment philosophy which now pervades all our thinking. Change the physical environment, says the biologist, and the species will be transformed. Change the economic environment, says the Socialist, and, if you make the right change, the race will be redeemed. Both statements rest on the same fundamental laws. As the many and highly important implications of this theory, are fully dealt with in subsequent lectures most of them will be passed here. We may note however, that whenever any nation in the modern world, produces, in the development of its industry, a Socialistic variation, that new feature at once proves its utility and is “selected” in the Darwinian sense, because it constitutes an advantage over the previous form of social organization, in that particular. This is the reason why the trust--which is socialistic and revolutionary in its essential tendences--is always victorious, in spite of the foolish ravings of the Hearst newspapers and the antediluvian twaddle of William Jennings Bryan. But Darwin’s crowning achievement is that he made the general theory of evolution impregnable by thoroughly and conclusively demonstrating it in his own field as a naturalist. From then on it was only a question of time as to when its application would be universal.