Progress in the diagnosis of morbid anatomic conditions has advanced by steps made possible by new opportunities for research: Thus, the first great opportunity came as a result of permission to study the human body by gross dissections; the second came through the invention of the earliest forms of magnifying lenses, and the third came as a result of methods of fixation, embedding and staining of tissues.
We are, I believe, at the beginning of still another opportunity presented by operative surgery through which we are supplied with perfectly fresh, living tissues that are being removed during the active process of disease instead of at the end of disease.
It is this opportunity which I wish to place before you—not so much for what has been accomplished as for what might be accomplished in the future. I have
lived through the evolution of, and the height of, the period of