Wherefore I take my stand firmly on the ground that the body of civilised man is capable not only of continuing the struggle for existence but of rising to a higher potentiality. So, returning to the point of differentiation between man and the lower animals, I am now convinced that we must seek for the cause of this physical degeneration not in the pressure of new circumstances of life, but in the progress from one state of being to the next. I maintain that in order to discover the solution of this twofold problem of universal disease and its universal remedy, we must look to this enormous growth of reasoning power, and to the consciousness and realisation of the means whereby the desired effect can be obtained. For the animal and the lower races of mankind do not perform physical acts by any process of reason. They are the servants of that strange directing law which governs the flower in its curiously ingenious devices to ensure cross-fertilisation, no less than the higher mammalia in the rules of their gregarious societies, the law for which we have found no better term than Instinct. It is this “instinct” which guides all the nervous muscular mechanisms of the animal’s anatomical structure, and is traceable as the motive in all functional processes. But in the physical economy of mankind this instinct is actually at war with, and is ever being controlled and superseded by conscious, directive reason. The number of man’s instinctive actions grows ever more limited, (1) as the result of a complete change of habit, and (2) more noticeably, as the outcome of a mental evolution which prompts him continually to seek a cause for every action, to analyse and endeavour to comprehend the secret springs of his being. Moreover civilisation, with its multitudinous problems of life and its perpetual interplay of personalities, demands even in the minutiæ of physical action a constant reasoning, a deliberate and comparatively rapid adaptation to surroundings such as instinct is quite unable to provide. Thus man’s whole body is a polity ruled by two governors whose dictates are not invariably consistent one with the other; and one governor is frequently disobeyed at the expense of the other. This fact, indeed, is obvious when it is thus considered, but we have to determine the possible outcome. There are three alternatives. The first, a return to the sole guidance of instinct, is unthinkable. The second, the continuance of this dual government, is the very condition which has led to the evils we seek to remedy. There remains the third, namely, that man’s physical evolution points to progress along the road of reasoned, conscious guidance and control. It was this last conclusion which over twenty years ago led me to investigate and to practise the means by which this conscious guidance and control could be obtained, so as to apply it to the eradication and prevention of human ills, and to the maintenance of