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!

... 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.

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

Sometimes the more measurable drives out the most important.

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

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.