Albert Nodon, President of the Bordeaux Astronomical Society tested, the radioactivity of living substances by a specially constructed electro-meter. He has found that the radioactivity of vegetable matter is of the same order as that of uranium. It is greater for the reproductive organs than for the other parts of the plants, it is also greater for freshly cut plants than for dried ones. Freshly dug earth had similar radioactivity. The insects showed three-five times greater radioactivity by unit of weight than uranium. Unfortunately Nodon's instrument, for constructional reasons, could not be applied to human beings.