Gabriel Deville, who has probably done more than any one else to popularize the ideas of Marx in France, has pointed out a very nice distinction here. Man, like all living beings, is the product of his environment. But while animals are affected only by the natural environment, man's brain, itself a product of the natural environment, becomes a cause, a creator, and makes for man an economic environment, so that man is acted on by two environments, the natural environment which has made man and the economic environment which man has made. Now in the early stages of human development, it is the natural environment, the fertility of the soil, climatic conditions, abundance of game, fish, etc., which is all-important, but with the progress of civilization, the natural environment loses in relative importance, and the economic environment (machinery, factories, improved appliances, etc.) grows in importance until in our day the economic environment has become well nigh all-important. Hence the inadequacy of the Henry George theory which places all its stress on one element of the natural environment, land, and wholly neglects the dominant economic environment. But while this economic environment, the dominant factor in human life, is the child of the brain of man, man in its creation has been forced to work within strict limitations. He had to make it out of the materials furnished him in the first place by the natural environment and later by the natural environment and the inherited economic environment, so that in the last analysis the material and economic factors are supreme. We Marxians are often accused of neglecting the intellectual factor and, as Deville says, a whole syndicate of factors; but we do not neglect them. We recognize their existence and their importance, but we do refuse to waste our revolutionary energy on derivative phenomena when we are able to see and recognize the decisive, dominant factor, the economic factor. As Deville says, we do not neglect the cart because we insist upon putting it behind the horse instead of in front of or alongside of him, as our critics would have us do. Now, if the economic factor is the basic factor, it behooves us to understand the present economic system--Marx's Law of Surplus-Value is the key to this system. FOOTNOTE: