One problem which confronts us is that knowledge so often outstrips practice. Experts acquire facts which are ignored, misused, or forgotten. Detroit makes cars so well that one can't drive them safely; power brakes are now so efficient that instead of running over one's victim, one can stop squarely on top of him. The problem is not new, of course, nor is it restricted. Medicine has many examples. In diabetes, for instance, the evidence favors strict control, and nobody has ever proved that glycosuria helps diabetics live longer. But practice lags far behind.
Doctors can be divided into three classes; those who watch things happen, those who make things happen, and those who don't know anything is happening. Joslin has made things happen in diabetes. He has shown that diabetics can live longer and has led the trend toward better control. He writes about his experiences and opinions in this