course, is concerned with the whole concent of whether the effects will be occurring at low levels in the same rate that they are occurring at high levels, and whether there is such a thing as threshold. In other words, is there some level below which nothing will happen? "Again, this is very difficult to estahlish. The evidence, as I see it, is very inconclusive in this direction, and if I had to choose, . . I would hesitate to accept this concept that a threshold does not exist." Dr, Shields Warren, a former Cirector of the Division of Riology 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 body can he repaired even though damaged, we find that at low levels of radiation there is no ohservable effect... . "T have favored the concent of a threshold for most carcinogenic agents for a number of reasons. First, that in our experiments with carcinogenic hydrocarbons, which are known to be 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 simole things in pvhvsics there is a threshold effect. For example, I can push very lightly against this stand of the micronhone, 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." purposes 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 unique in nature and neither behave like nor have the same effect as stahle 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 “lLinear" 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 inaporopriateness of the word “proportionality” LO1ub4ke