Data are presented that show a marked species difference in the degree of damage and in the course of events seen in the bone marrow and peripheral blood after a given dose of radiation. The data taken together indicate strongly, but do not prove, that the picture seen results primarily from damage to the stem cell population. This damage to the stem cells is manifested later in the more mature differentiating cells of the marrow, and in the peripheral blood. The picture seen results both from death of stem cells, and also injury leading to reduced proliferative capacity, with later death of the injured stem cell and all of its progeny. Thus the picture seen is a result of both quantitative and qualitative changes resulting directly from the exposure of the stem cells, and species differences relative to sensitivity and time course of events appear to depend to a large degree on differential sensitivity of the bone marrow stem cell populations to death and injury. (auth)

Science is impure in two ways. There is not a 'pure' science. By this I mean that physics impinges on astronomy, on the one hand, and chemistry on biology on the other. And not only does each support its neighbors but derives sustenance from them. The same can be said of chemistry. Biology is, perhaps, the example par excellence today of an 'impure' science. Beyond this, there is no 'pure' science itself divorced from human values. The importance of science to the humanities and the humanities to science in their complementary contribution to the variety of human life grows daily. The need for men familiar with both is imperative. We are faced today with a social decision resulting from our progress in molecular genetics at least equal to, and probably greater than, that required of us twenty years ago with the maturity of nuclear power.

Photocopy of a magazine article by Hugh Aynesworth, discussing the assassination of President John F. Kennedy and the investigations made by New Orleans District Attorney Jim Garrison.