# Popular Science Monthly/Volume 55/July 1899/Minor Paragraphs

Layout 4
Of the twelve genera and fifty species of known North American frogs and toads, Mr. William L. Sherwood says, in his paper in the Proceedings of the Linnæan Society, New York, that five genera and fifty species are found in the vicinity of New York city. Some of these are less secretive in habit than salamanders, and therefore much better known. As ponds and ditches have been drained, the aquatic forms have removed to greater distances from human dwellings, and only the more terrestrial toad and arboreal tree frogs have remained. All of our species have been described, but the author believes that the first mention of the cricket frog being found in this region is in a paper on salamanders, read by him in 1895. The breeding habits of these animals vary, but all lay their eggs in water or moist places. The purely amphibious and really aquatic species are three. Of the other eight species, one is burrowing, five tend to be terrestrial, inhabiting the woods and fields, and two are arboreal. The eggs are laid in gelatinous envelopes, which swell after leaving the adult. At the time of hatching the young tadpole has three pairs ​of external gills, but no mouth or anal opening. Two small suckers, just back of where the mouth is to appear, enable it to cling to aquatic plants and prevent its dropping to the bottom of the pond and getting smothered in the mud. It soon develops into a tadpole, and proceeds to its development; but if prevented from coming to the surface of the water no metamorphosis takes place, and the changes are delayed by cold and dark.
At a meeting recently held in Berlin in behalf of a German antarctic exploration, Dr. von Drygalski, speaking of the scientific, practical, and national importance of the enterprise, said that from a geographical point of view the fundamental problem attached to the south polar region—the verification or disproof of a polar continent—is still unsolved. No less important questions likewise await solution with respect to the geological structure and character of the southern lands—so important in connection with a knowledge of volcanic action and the supposed former connection of South America and Australia—and with respect to the conditions of inland ice. Even the study of the floating ice broken away from the main mass may lead to important conclusions as to its mode of origin and the nature of the land from which it comes. Other problems to be investigated are the origin of the cold ocean currents that take their rise in the south, the conditions of the atmospheric pressure and temperature in that region, and the questions relating to terrestrial magnetism, which have a very important bearing on the practice of navigation. The present seems to be a particularly favorable period for the resumption of south polar research by reason of the unusual amount of drift ice which has within the last few years broken away from the main mass, and because, according to Supan, we are passing through a warmer temperature period.
Over and above the statistics and the bare record of facts the annual reports of the Perkins Institution and Massachusetts School for the Blind, afford a continuous and growing interest to friends of suffering mankind in their stories of the development of mental life and illumination. Pupils come there blind and deaf, and apparently without any avenues of intelligent communication with the outer world, and are there brought to full consciousness and keenness of intellect that would be remarked even in many persons possessed of all their senses perfect from birth. The record began with Laura Bridgman, was continued with Helen Keller, and has been occupied for five or six years past with the wonderful mental growth of Elizabeth Robin, Edith M. Thomas, and Tommy Stringer. Before Dr. Howe began with Laura Bridgman, such things would have been deemed impossible and not to be thought of.