-2information and the techniques which you learn here. The second one is the ever present worry about the future conflict in wiich contamination by radioactive materials will be a major problem for all technical and professional men, As physicians and technical men, groups such as this will. have to be the backbone of any defensive or pretective organizations that are set up. It is not unlikely that Dr. Bryan will discuss the contamination aspects of the laboratory problem very extensively when you come to deal with the active radioactive materials later on in the course I would like to make a few remarks about the application of nuclear physics to medicine and biology, particularly emphasizing the dynamic aspects of biological phenomena, Perhaps I am sensitizei to this a bit because recently I have been argu- ing with the physicists a great deal. The physicist, chemist and engineer, when they are dealing with experiments] programs, think in terms of a very small percentage of error, because they can deal in general with rather fixed conditions end situations—and by raking two or three measurements and then using a lot of mathematics they can come out. with an answer which has a chance at least of being quite precise. In bio- logical problezs you are dealing «ith e dynamic systen which is continually changing. Of course the physicist is also, to a certain extent, but not just in this same way. In dealing with biological problems you have to bring a little different point of view to bear upon the experimental obsezvations cr the factual observations. In this same regard we have the greatest misconceptions today in both the national and international picture where medical and biolorical laymen attempt to apply static and precise explanations to phenomena occurring in jiarge areas of contamination. You cannot just say you are going to have so many microcuries or curies of contaminating material spread in such and such an area uniformly. There is no such thing as uniformity on a large