" T he only use of a knowledge of the past is to equip us for the present," said Alfred North Whitehead,1 and Herbert Muller2 put it even more succinctly: "The past answers only to a present interest." In the past 60 years, man has gradually gained some degree of control over pneumonia. In the process, clinicians and investigators were often frustrated and discouraged, yet many of the frustrations opened the door to new methods of diagnosis and therapy. I believe the story is worth telling because it is filled with lessons that we can use profitably today.
Medical history can be written in terms of important discoveries or their practical application. In no disease are these more closely intertwined than in pneumonia, and I shall discuss both. However, because popular writers have dwelt at length, and often with hyperbole, upon how the discoveries occurred, I shall pay particular