course, is concerned with the whole concept of whether the effects will he levels, and whether there is such a thing as threshold. occurring at low levels in the same rate that they are occurring at high In other words, is there some level helow which nothing will happen? "Again, this is very difficult to estahlish. is very inconclusive in this direction, The evidence, as I see it, and if I had to choose, ..., IY would hesitate to accert this concept that a threshold does not exist," Dr. Shields Warren, a former Director of the Division of Rinlogy and Medicine of the Atomic Energy Commission indicated he favored a threshold effect, = "With acute or chronic radiation there is what is called a threshold effect in body cells. In other words, because many cells can continue to function even though irradiated and manv cells in the hody can be repaired even though damaged, we find that at low levels of radiation there is no observable effect ,... "T have favored the concert of a threshold for most carcinogenic agents for a number of reasons, First, that in our experiments with carcinogenic hydrocarbons, which are known to he derived from such substances as coal tar, we find that a threshold exists for them. We find that, with many of the medicines that are commonly used for one or another effect on cells, there is a threshold effect to these medicines, We know, by analogy with simple things in physics there is a threshold effect. For example, I can push very lightly against this stand of the microphone, and it will not move until I reach the threshold of where that push is greater than the friction which tends to hold it still." . ourposes there is no threshold. Thus he is attempting to prove a generality with a generality. 2, Also overlooked in Potter's exposition is the unalterable fact that radioactive substances are unicue in nature and neither behave like nor have the same effect as stable elements. For example, it is possible that the ingestion of certain chemicals (like some pesticides, or other poisons, like cyanide) may cause chemical and thus genetic damage within the body's somatic cells. It has not been proven, however, that such ingestion will cause hereditary damage in sex cells lasting for generations, as does radiation. Potter goes on to state: "Linear projections or extrapolations are a semantic fiction originating in the Euclidean concepts that arose in the days when the earth was called flat and everything in geometry was worked out in terms of rectilinear and rectangular frames of reference, a state of affairs that still plagues the prohlems of solid state physics." Potter's assertion here is not entirely clear, It may be that he is playing a semantic game himself with the word "linear" or with the method of expressing effects in terms of a two-dimensional chart using a straight line. Could he just as effectively apply the inappropriateness of the word "proportions +" 38