“Bacteria,” says Dr. Coolidge, “have been rayed, and an exposure of a tenth of a second has been found sufficient to kill even highly resistant bacterial spores. Fruit flies, upon being rayed for a small fraction of a second, instantly showed almost complete collapse, and in a few hours were dead.” This may lead to the application of cathode rays as a germicide, but their effect on higher forms of life shows that their unskilled use would be most dangerous. For example, Dr. Coolidge relates: “The ear of a rabbit was rayed over a circular area one centimeter in diameter for one second. After several days a scab formed which fell off a few days later, taking the hair with it. Two weeks later a profuse growth of snow-white hair started which soon became much longer than the original gray hair. Another area was rayed for 50 seconds. In this case, scabs developed on both sides of the ear, which scabs later fell out, leaving a hole. The edge of this hole is now covered with snow-white hair.” A very interesting problem to scientists relates to the question as to whether or not insects are color-blind. It may be that we now have at least a partial answer to this vexed question, and in terms of ultra-violet radiations. Dr. Frank E. E. Germann, of Cornell University, calls attention to some recent experiments which show conclusively that at least one kind of insects (flies) have a range of vision in the ultra-violet, just as we have in the visible spectrum. It was also made “perfectly evident that flowers do have their characteristic ultra-violet radiations” (_Science_, March 26, 1926, page 325). It is due “to our own egotism that we call the insect color-blind.” A given type of insect might in reality be visiting flowers of the same color as far as it was concerned, while to us it appeared to be visiting flowers of all colors. “Might not two flowers, one red and one blue, both give out the same group of wave lengths in the ultra-violet, and thus be identical in color to an insect seeing only the ultra-violet? Moreover, what is to prevent two different kinds of red flowers from giving out two entirely different sets of wave lengths in the ultra-violet, and thus appearing to have entirely different colors to an insect?” In a very real sense, science is only at the beginning of the discoveries it will yet make in its investigations of the nature and action of ultra-violet, cathode and X-rays. FOOTNOTES: [3] It is interesting to note in this connection that Kuzelmass and McQuarrie have suggested that oxidation of cod liver oil gives rise to ultra-violet radiation. (See _Science_, September 19, 1924.) [4] Paper read before the 66th meeting of the American Chemical Society, held in Milwaukee, Wis., September 10th to 14th, 1923.