Henry T. Bahnson, after graduating from Harvard in 1944, had begun his surgical training as an intern at Hopkins. Denton Cooley was also an intern. It was difficult for interns and members of the house staff to find time to work in the laboratory, but these two succeeded. Working at night, they performed a series of experiments on wringer (washing- machine) injuries. Alternating in watching their animals throughout the night, they rarely got much sleep. Dr. Bahnson also found time a few years later to practice vascular suturing by performing subclavian-topumonary-artery anastomoses, as had been done at Vanderbilt in earlier attempts to produce pulmonary hypertension. His interest in cardiovascular surgery was so great that he began working in the laboratory almost immediately upon completion of his residency in 1951. Many investigators were working on the development and perfection of a pump oxygenator for use in open-heart surgery. Dr. Bahnson began by trying rotating disks as an oxygenator but changed to a bubble oxygenator. He worked diligently on the project, using all available time while carrying on his clinical responsibilities as a member of the full-time surgical staff.
By the early 1950s, the Professor was aware that the lead in further advancement in the field of cardiovascular surgery was being taken by other institutions and individuals; needless to say, he was not happy about it. Much had been accomplished in the treatment of cardiac diseases by the use of "blind" techniques. So much more could be accomplished, so many life-saving techniques developed, if one could see what he was doing. Many problems simply could not be corrected blindly. This meant the perfection of an artificial circulation, a heart-lung machine that would take over the function of the heart and lungs while the heart was opened for surgery. By the mid-1950s, with no open-heart procedures being performed on his service, Dr. Blalock decided that Hopkins must make progress in cardiovascular surgery. He felt that the man for the job -- deeply interested, extremely capable, and well prepared for the task -- was on his staff. He assigned the responsibility for the development of a program for open-heart surgery to Dr. Bahnson. He also asked Dr. Frank Spencer, who just completed his residency, to work with him. After years of conscientious effort, in March 1956 they performed their first open-heart procedure with the use of a heart-lung machine that in-