Human life implies adventure, and there is no adventure without struggles and dangers.

... each type of civilization has had diseases peculiar to it and at each period the various social groups in any community also have differed in this regard.

The most important pathological effects of pollution are extremely delayed and indirect.

Clearly, health and disease cannot be defined merely in terms of anatomical, physiological, or mental attributes. Their real measure is the ability of the individual to function in a manner acceptable to himself and to the group of which he is a part.

Gauss replied, when asked how soon he expected to reach certain mathematical conclusions, that he had them long ago, all he was worrying about was how to reach them!

In man, at least, satisfaction is commonly followed by boredom.

Social evolution may be the result of intention, but it rarely, if ever, produces the result intended.