M. Danysz is convinced that all animals, probably all forms of life, would succumb to the destructive force of radium if employed in sufficient quantities. "I have no doubt," said he, "that a kilogramme of radium would be sufficient to destroy the population of Paris, granting that they came within its influence. Men and women would be killed just as easily as mice. They would feel nothing during their exposure to the radium, nor realize that they were in any danger. And weeks would pass after their exposure before anything would happen. Then gradually the skin would begin to peel off and their bodies would become one great sore. Then they would become blind. Then they would die from paralysis and congestion of the spinal cord." Despite this rather gloomy prospect, certain experiments at the Pasteur Institute may encourage us to believe that, for all its menace of destruction, radium is destined to bring substantial benefits to suffering humankind. The substance of these favourable experiments is that, while animal life may undoubtedly suffer great harm from radium when used in excess or wrongly used (the same is true of strychnine), it may also derive immense good from radium when used within proper bounds, these to be set when we have gained a fuller knowledge of the subject. Meantime it is worthy of note that some of M. Danysz's animals, when exposed to the radium for a short time, or to radium of lower intensity, or to radium at a greater distance, have not perished, but have seemed to thrive under the treatment. But the most startling experiment performed thus far at the Pasteur Institute is one undertaken by M. Danysz, February 3rd, 1903, when he placed three or four dozen little worms that live in flour, the larvæ _Ephestia kuehniella_, in a glass flask, where they were exposed for a few hours to the rays of radium. He placed a like number of larvæ in a control flask where there was no radium, and he left enough flour in each flask for the larvæ to live upon. After several weeks it was found that most of the larvæ in the radium flask had been killed, but that a few of them had escaped the destructive action of the rays by crawling away to distant corners of the flask, where they were still living. But _they were living_ _as larvæ, not as moths_, whereas in the natural course they should have become moths long before, as was seen by the control flask, where the larvæ had all changed into moths, and these had hatched their eggs into other larvæ, and these had produced other moths. All of which made it clear that the radium rays had arrested the development of these little worms. [Illustration: M. CURIE TESTING DIAMONDS AT A RECEPTION AT LILLE.]