The evolution of concepts about the arteriosclerotic plaque is brilliantly unfolded in a newly published symposium which ought to be read by all investigators in the field. The articles are of uniformly high standard; the discussions, however, sometimes appear undisciplined. The results of current, refined methods of investigation are presented—electron microscopy, paper chromatography, fluorescent antigen-antibody reactions, and radioactive tracers. It is reassuring to learn that these more refined methods have yielded findings which substantiate views derived from older, more elementary research, and even those which might seem self-evident without experimentation. No one would quibble with the conclusion that large arteries tend to have more plaques than small ones, and that blood pressure plays some role in arteriosclerosis, even if no experiments had been done on the point.
While the techniques of the studies are highly complex, the findings are summarized in relatively simple form. We quickly learn that basic questions,