rI~he Zumbro is a venerable hotel for ambulatory patients<br >and guests who come to Rochester， Minnesota， for their annual<br >checkups at the Mayo Clinic. Across the dark wood frame over<br >the entrance to the dining room is an inscription: WE KNOW<br >YOUR OPERATION IS INTERESTING， BUT PLEASE DON T DISCUSS<br >IT IN HERE. Except for the following introductory paragraphs，<br >which relate more to the subject of this book than to the medi-<br >cal history of its author， I intend to abide by the Zumbro<br >management s good advice.<br > One bright morning in the spring of 1957， I entered a mobile<br >x-ray unit on the Vanderbilt University campus， 61led out a<br >card， and， before the pretty attendant had a chance to instruct<br >me， assumed the proper stance before the screen. Having un-<br >dergone surgery seven years earlier for coarctation of the aorta<br >(a narrowing of the first large artery out of the heart)， I was an<br >old hand at x-ray protocol. I was expert on the correct place-<br >ment of blood pressure cuffs， too， and knew where and how to<br >locate and puncture my best veins. Such a small， simple vanity<br >prompted me to enter that x-ray unit. I was recently married，<br >