More sensational than tests of intelligence is the possibility of controlling the emotional life through the secretions of the ductless glands. It will be possible to make people choleric or timid, strongly or weakly sexed, and so on, as may be desired. Differences of emotional disposition seem to be chiefly due to secretions of the ductless glands, and therefore controllable by injections or by increasing or diminishing the secretions. Assuming an oligarchic organization of society, the State could give to the children of holders of power the disposition required for command, and to the children of the proletariat the disposition required for obedience. Against the injections of the State physicians the most eloquent Socialist oratory would be powerless. The only difficulty would be to combine this submissiveness with the necessary ferocity against external enemies; but I do not doubt that official science would be equal to the task. It is not necessary, when we are considering political consequences, to pin our faith to the particular theories of the ductless glands, which may blow over, like other theories. All that is essential in our hypothesis is the belief that physiology will in time find ways of controlling emotion, which it is scarcely possible to doubt. When that day comes, we shall have the emotions desired by our rulers, and the chief business of elementary education will be to produce the desired disposition, no longer by punishment or moral precept, but by the far surer method of injection or diet. The men who will administer this system will have a power beyond the dreams of the Jesuits, but there is no reason to suppose that they will have more sense than the men who control education to-day. Technical scientific knowledge does not make men sensible in their aims, and administrators in the future, will be presumably no less stupid and no less prejudiced than they are at present. CONCLUSION It may seem as though I had been at once gloomy and frivolous in some of my prognostications. I will end, however, with the serious lesson which seems to me to result. Men sometimes speak as though the progress of science must necessarily be a boon to mankind, but that, I fear, is one of the comfortable nineteenth-century delusions which our more disillusioned age must discard. Science enables the holders of power to realize their purposes more fully than they could otherwise do. If their purposes are good, this is a gain; if they are evil, it is a loss. In the present age, it seems that the purposes of the holders of power are in the main evil, in the sense that they involve a diminution, in the world at large, of the things men are agreed in thinking good. Therefore, at present, science does harm by increasing the power of rulers. Science is no substitute for virtue; the heart is as necessary for a good life as the head.