ABSTRACT
A discussant always hopes to pick up a latent theme in a conference and justify his presence by bringing this theme to the attention of everyone who has been saying it all along. It is to be hoped that this practice is worthwhile, that is, that it is of some use to investigators to have someone say again to them in somewhat different words what they themselves have said. Or perhaps it is the case that the reader of the volume is waiting for the discussant to simplify the issues and make a bald statement that the authors of the original papers were too sophisticated to affirm. In any case, from my point of view a happy situation seems to exist; there does seem to be a latent theme to the conference, and no one seems yet to have boldly asserted what it is. Thus, as a discussant, I am relieved to find that I have a role.
