“Because of this fact,” says a writer for _The Popular Science Monthly_ (June, 1923), “a group of physicians interested in the use of radium as a curative stimulant have invented an ingenious device for imparting radioactive properties to ordinary water. As designed for use in the home, this instrument consists of a case containing an arrangement of glass tubes and vessels in which emanations from radium salts in solution are imparted to air, which is then mixed with the water. “A much simpler apparatus, available for office use, somewhat resembles a hypodermic syringe, containing special capsules of radium salts. Pushing a plunger forces air through the radium capsules and into a glass of water and is said to make the water radioactive. The doses of radium in each case are constant, because radium emanates at a constant rate, and only a certain amount can be dissolved in water, no matter how many times a day the apparatus is brought into use. “Whether radium treatment will prove able to restore youth to old age, grow new sets of teeth and perform other marvels that its more ardent supporters predict for it, only time will tell. “If radium treatment proves to facilitate the process of cell elimination, it will have gone a long way toward delivering the world from its enemies of disease.” The philosopher-scientist, Le Bon, makes bold to suggest that light-waves which are invisible to human eyes may be perceptible to nocturnal animals, which would include most of the lemurs and the felines, and some other beasts which seem to be capable of finding their way and carrying on their predatory or other activities in the dark. “To them,” says Le Bon, “the body of a living being, whose temperature is about 37° C., or about 98° F., ought to be surrounded by a luminous halo, which the want of sensitiveness of our eyes alone prevents our discovering. There do not exist in nature, in reality, any dark bodies, but only imperfect eyes.” Le Bon has also said that the human body is sufficiently radioactive to photograph itself by its own rays, if we could find a substance sensitive to these radiations, as the photographic plate is to the actinic rays. Nothing would then be easier, he declares, than to photograph a living body in the dark without any other source of light than the invisible light which it is continually emitting. Some recent (1924) experiments of the French scientist, Dr. Albert Nodon, seem to afford the actual proof of Le Bon’s _a priori_ conclusions. In the presence of a number of noted scientists, Dr. Nodon exhibited three photographic plates on which were unmistakable light impressions, which, he claimed, were caused by the rays emitted by a radioactive mineral, an insect, and a green leaf, which had been placed on the emulsion side of the plates in a dark-room.