Biologically, man is still the great amateur of the animal kingdom; he is unique in his lack of anatomical and physiological specialization.

With reference to life there is not one nature; there are only associations of states and circumstances, varying from place to place and from time to time.

But solving problems of disease is not the same thing as creating health and happiness. (...) Health and happiness are the expression of the manner in which the individual responds and adapts to the challenges that he meets in everyday life.

Eradication of microbial disease is a will-o'-the-wisp; pursuing it leads into a morass of hazy biological concepts and half truths.

What happens in the mind of man is always reflected in the disease of his body.

There is a demon in technology. It was put there by man and man will have to exorcise it before technological civilization can achieve the eighteenth-century ideal of humane civilized life.

Men are naturally most impressed by diseases which have obvious manifestations, yet some of their worst enemies creep on them unobtrusively.