Human destiny is bound to remain a gamble, because at some unpredictable time and in some unforeseeable manner nature will strike back.

Each civilization has its own kind of pestilence and can control it only by reforming itself.

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

Nature always strikes back. It takes all the running we can do to remain in the same place.

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

... 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.

One may wonder indeed whether the pretense of superior health is not itself rapidly becoming a mental aberration.