On the Local and Generalised Action of Radium and X Rays upon Tumour Growth

In both cases a gradual change of effects is observed according to the dose of radiation. Actively growing malignant cells, given a large dose of radiation, degenerate and die when re-inoculated into a living animal; a dose short of this quantity causes the tumour cells to grow at a slower rate than they would do normally, but if given a very small dose, the cells appear to be stimulated rather than hindered in their subsequent growth. Prolonged exposure of the animal to the rays results in severe wasting and death; with a reduction in the exposure a growing animal will retain its health, but with a diminished rate of increase of body weight. As the dose of radiation becomes less, a stage is reached when the rate of increase of body weight exceeds that of the normal animal; and, when the animal is given these very small doses of X-rays, it is found to develop a state of increased resistance to an implanted tumour. Such briefly are the chief effects to be considered when devising methods by which a lethal dose of radiation may be given to a tumour without reducing the resistance of the animal. The experimental data in this paper will be dealt with as follows:(A) The effect of the rays in various doses upon malignant cells, before inoculation.