Boys' Second Book of Inventions. Ray Stannard Baker

produced other moths. All of which made it clear that the radium rays had arrested the development of these little worms.

      More weeks passed, and still three or four of the larvæ lived, and four full months after the original exposure one larva was still alive and wriggling, while its contemporary larvæ in the other jar had long since passed away as aged moths, leaving generations of moths' eggs and larvæ to witness this miracle, for here was a larva, venerable among his kind, that had actually lived through three times the span of life accorded to his fellows and that still showed no sign of changing into a moth. It was very much as if a young man of twenty-one should keep the appearance of twenty-one for two hundred and fifty years!

      Not less remarkable than these are some recent experiments made by M. Bohn at the biological laboratories of the Sorbonne, his conclusions being that radium may so far modify various lower forms of life as to actually produce new species of "monsters," abnormal deviations from the original type of the species. Furthermore, he has been able to accomplish with radium what Professor Loeb did with salt solutions—that is, to cause the growth of unfecundated eggs of the sea-urchin, and to advance these through several stages of their development. In other words, he has used radium to create life where there would have been no life but for this strange stimulation.

      So much for the wonders of radium. We seem, indeed, to be on the border-land of still more wonderful discoveries. Perhaps these radium investigations will lead to some explanation of that great question in science, "What is electricity?"—and that, who can say, may solve that profounder problem, "What is life?"

      At present there are two theories as to the source of energy in radium, thus stated by Professor Curie:

      "Where is the source of this energy? Both Madame Curie and myself are unable to go beyond hypotheses; one of these consists in supposing the atoms of radium evolving and transforming into another simple body, and, despite the extreme slowness of that transformation, which cannot be located during a year, the amount of energy involved in that transformation is tremendous.