Page:Popular Science Monthly Volume 24.djvu/150

140 the faradaic current, and vigorous feeding—to which the appetite was found ready to respond. Dr. Playfair attributes the chief value of the treatment to the fact that it appeals not to one only but to many influces of a curative character. The "Louisville Medical News," reviewing the cases, believes that the imagination is the most prominent agent in effecting the cures, and is ready to class them with "faith-cures."

Phosphorescence in Plants.—M. Crié remarks, in a communication to the French Academy of Sciences, that "it is known that the flowers of phanerogams are capable under certain circumstances of producing phosphorescent light. The phenomenon has been verified, especially of the nasturtium and the marigold. Some years ago I myself saw phosphorescent lights emitted in stormy weather from the flowers of the Tropóelum majus, cultivated in a garden. The emission is especially noticeable in the mushrooms. The agaric of the olive, which grows in Provence, at the foot of the olive-trees, is distinguished for its white, quiet, uniform light, which resembles that of phosphorus dissolved in oil." Several other species of luminous agaric are known, but the property is not limited to that genus. The Rhizomorpha, or the vegetative apparatus of a considerable number of mushrooms, are also phosphorescent. These cryptogams, which are common in mines, give a light by which miners can see their hands. The luminous threads of Rhizomorpha subterranea are easy to perceive in the Pontpean mine, near Rennes. Luminous filaments of a rhizomorpha have been observed in branches of the elder. The Xylaria polyrnorpha, collected from old stalks in a garden, has been seen to emit a feeble white glow, like that of phosphorus in the air.

Professor Virchow on Humboldt.—A monument to William and Alexander von Humboldt was unveiled at the University of Berlin on the 28th of May. Professor Virchow delivered an address on the occasion, in which he spoke in the highest terms of the character and value of the work of the two brothers. "We older men," he said, "who have learned personally from Alexander von Humboldt, and have in part worked with him, feel our strength renewed when we see how the memory of the time of the new birth of our people is perpetuated to posterity in the many monuments of our city. One who walks through our streets will discover that Goethe and Schiller, Stein and the Humboldts, Bliicher and Schwarnhorst, did not casually live side by side, but that a recognizable connection prevailed in their development, and wove their works together to a single end. Every German will look with pride upon the men who have risen from out of the midst of the people to the highest places of honor, because they wakened and unfettered the noblest forces of the nation. Especially could our academic youth, who have these models before their eyes every day, learn from the history of such men what recompense genuine work can gain. Humboldt, who completed the 'Cosmos' in extreme age, and who wrote in the last year of his life, 'For thirty years I have had no rest, except at night,' was at one time a sickly lad, whose teacher in the first years of his childhood doubted whether he would ever manifest any more than the most ordinary mental faculties. He, whose youth fell in an age when hardly anything but speculative wisdom, poetic invention and dogmatic tradition were held in honor, had, in his incessant struggles in nearly all the domains of natural science, brought into avail that stronger objective method of thought, comprehensive in its grasp, which has since become the pride and the common estate of the learned of modern times. When he at last, like the world-sages of antiquity, united in himself all the knowledge of his time on natural subjects, and with it the comprehension of its historic growth, it was not the knowledge of a compiler that he displayed, but the fruit of long special work in each single field. He served in the ranks as a national economist and as a miner, as an astronomer and as a physicist, as a chemist and as a geologist, as an anatomist and as an experimenter in vegetable and animal physiology. He was the first scientific traveler who independently studied all the natural and political conditions of the countries visited by himself. Political and physical geography, the study of terrestrial magnetism, plant-geography, and ethnography, grew under his care to be