Preparation of heparin and its use in the first clinical cases.

M ANY OF UJ8, who were friends of the late Dr. Jay McLean, had looked forward with great pleasure to seeing him again at this tiune and to discussing the problems wlhich occupied so much of his attention. We all join Dr.. Wright in paying tribute to Dr. MlcLean, the discoverer of heparin, and to Professor W. H. Howell and his colleagues, who extended this work and focused our attention oIn many of the most important problenis in this field. A number of years ago Dr. McLean wrote to me and asked if we would take the responsibility for his collection of notes and reprints and other documents relating, to heparinr. I was honoured and extremely 1leased to accept this invitation. It is almost always true that a very careful search of the literature will reveal papers which anticipate, to varying degrees, the discovery of a signal advance ill medical or other sciences. In 1912, Doyon' published a paper in which he describes anl attempt to isolate and characterize ail anticoagulant released by the injection of peptone in a dog. This work was interrupted by World War I. There are a number of other intriguing findings in the literature, for example that of Schmidt2 in 1892, but their significance could only be appreciated after the discovery of heparin by Dr. McLean13 ill 1916. Onl November 14, 1940, Dr. Jay MeLean wrote me a long, letter describing the whole history of his work on heparin, and a great deal about his subsequent researches. I will quote parts of this letter.