Soon after I returned to America I received a large engraving of Cannizzaro inscribed in his own hand-writing. The portrait represents him as sitting and the expression on his benign face is one of confident repose, yet I shall always think of his statue of Mercury for it typifies the swift message of tnLhthat sped from the youthful Cannizzaro throughout the world of chemistry in those dark days so many years ago.
Dark Colored Rubber Wears Better Than Light. The color of a rubber article may prove t o be one of its most important properties, for recent experiments in the rubber laboratory of the U. S. Bureau of Standards have shown that the darkest colored rubber objects stay "alive" longest when exposed to sunlight. A piece of light colored rubber retains its life very well when it is kept in the dark but deteriorates rapidly in the light. Tests were made and it was learned that different colors caused rubber to age a t different rates. The advantage of using dark-colored compounds in rubber articles that must be exposed to the sun is pointed out. Two test compounds were made; one to which two per cent carbon black was added as coloring matter and another which was colored with the same amount of red oxide. Three samples of rubber, one uncolored, one black, and the other white, were together exposed to sunlight lor six months. Tests made a t intervals to determine the rate of deterioration of each, indicated that the uncolored compound lost its life about five times as fast as the black but only about two times as fast as the red. The quantities of coloring matter added were not enough t o affect the strength of the compounds.Science S m ' c e Sprayed Apples Safe, Expert Announces. The bubble of British a h r m over arsenic poisoning derived from the spray materials left deposited on apples imported from Canada has been pricked by results of a recent scientific survey and analysis. Dr. Prank T. Shutt, Dominion chemist, has found after extensive tests that a very large proportion of Canadian sprayed apples are entirely free from arsenic. The samples of fruit on which arsenic was found have such small quantities as t o require four dozen apples to supply the largest dose permitted by medical practice, he declares in a reoort of his fmdiu~s. . There has been considerable agitation over sprayed apples as a source of recent cases of arsenic ooisonina in the British lay press and in medical iournals, and the chem.. ical analysis was undertaken to ascertain the precise status of sprayed apples as s menace to health. There has been a considerable falling off in the importation of Canadian apples as a result of the generally expressed alarm, it is said.-Science Service Animal Experiments Are Open to Public. Experiments on animals necessary for the progress of medical knowledge do not take place behind barred doors, despite the claims of the antivivisectionists. The animal rooms of medical laboratories are always open t o responsible visitors according t o a survey of the medical colleges and research institutes of the country, recently conducted by the American Association for Medical Progress. Several directors extend special invitations to officers of humane societies so that they can see for themselves the exact conditions under which animals are kept for experimental purposes. Some laboratories will only receive visitors who have seen operations performed on human beings because it is argued that only in this way can a lay person appreciate the similarity between the two and the care taken against inflicting pain and avoiding infection.-Science Service
