THE DISCUSSION OF THIS PAPER caused me some apprehension since the content of the material remained a total stranger to me until a few days ago. My discomfort was not relieved when I recalled that John Spiegel does not require a prepared text in order to deliver a first class presentation. I once heard him do it as a last-minute pinch hitter and he did a superb job. A realization of this state of affairs did not ease my task.

My anxiety was mildly relieved when the paper arrived practically at the last minute. A brief glance at the material and turning the pages quickly evoked instantaneous interest in me despite the excessive time pressure. In the meantime, I had the good fortune