By custom the presiding officer of this society is ex-pected to open the scientific session with a presidential address. This obligation, which I accept with grave mis-givings, I shall try to fulfill in as short a time as possible, so that we may proceed promptly to the main program. The thesis which I should like to presentbriefly, is that today we find ourselves in, or rapidly approaching, the" logarithmic phase" of medical progress. The choice of my crude analogy is, of course, condi-tioned by my own past training and interests. Reference to the bacterial growth curve may be justified, however, on the grounds that itis familiar to nearly everyone in medicine (Figure 1). Youwill recall that the logarithm c 0.