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Page:Popular Science Monthly Volume 53.djvu/593

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FRAGMENTS OF SCIENCE.

at work upon it. The material was sent into all Christian countries, and its name is found in most European languages. Queen Elizabeth was vestita di tabi d'argento et bianco (dressed in silver-and-white tabby) when she received the Venetian envoy Scaramelli in 1602. Samuel Pepys records of a certain day that he put on his "false taby waistecoate with gold lace." And Miss Burney, on the occasion of the birthday of the princess royal, at Windsor, in 1786, appeared in a gown of "lilac tabby." Dr. Johnson explains in his dictionary that tabby is "a kind of waved silk," and adds that the tabby cat is so named from the brindled markings of its fur.

The "pine-barren region" of the Atlantic coast, sporadic and narrow in New England and Long Island, broadens as we go south, and in the Carolinas often extends to a distance of about eighty miles from the sea. It has a flora of its own, and quite distinct from those of the hill and mountain regions back of it. Mr. Thomas H. Kearney, Jr., reports in the new periodical The Plant World that he has found spots where a large proportion of this flat-country flora occurs in nooks of sandy ground hidden away among the high regions of the Appalachians. Especially along the French Broad River, in East Tennessee and western North Carolina, "there is a notable incursion of plants usually considered typical of the coastal plain. In some places these 'miniature pine barrens,' with their growth of pitch and scrub pine and the herbaceous plants that associate themselves with them, push their way up on the lower, near-by ridges, crowding among the oaks and chestnuts that are the rightful tenants. Such islands of coastal vegetation have been observed at several places in this mountain region."

Every one is acquainted with those water plants, the duckweeds, which appear to the eye as small oval leaves floating on the surface of ponds and streams, so closely packed together as to form an apparently continuous mass, often of considerable extent. Mr. Charles Henry Thompson, who has made a study of them, finds four well-defined genera and about twenty eight species in their order, the Lemnaceæ, distributed throughout the torrid and temperate zones. In our range the four genera are represented by about thirteen species and one variety, of which two species and the variety are probably peculiar to it alone, and ten are found only in the western hemisphere. There are difficulties in classifying them, because the species have a strong tendency to vary widely according to the surroundings, and because the flowers and fruit are only partially known in some species and not at all in others. Then some species may have two or three marked stages of growth differing from each other so widely as to give rise to different specific names for each. In the third of these stages, which the author calls the "resting stage," "winter fronds" are formed, and the plant sinks to the bottom, to rise again in the spring. Somewhat similar modified fronds are formed when the ponds recede or dry up, to start out again in healthy vegetation when the moisture returns.


NOTES.

A very interesting excursion is offered by La Nature to its subscribers, from the 4th till the 16th of August, to the central plateau of France, with its caves, gorges, and mountain ascents. An itinerary has been prepared contemplating a visit each day to some of the remarkable and curiously attractive spots in which the region abounds, including an experience of subterranean navigation in the Gouffre of Padisac, the Gouffre of Réveillon, the mines and factories of Decazeville, the buried forest of la Mougudo, the viaduct of Garabit, the Course du Sauveterre, navigation of the Gorges of the Tarn, the Grotto of Dargillan, and ascensions of the Puy Mary, with lunch on the summit, and of l'Aigoual. The entire cost of the excursion, covering all ordinary expenditures, is two hundred and fifty francs, or fifty dollars, from Rocamadour, where it begins, to Vigan, where it ends, with reduced railroad fares going and coming.

Dr. Stuart Jenkins has not been satisfied with the adequacy of the Darwinian doctrine of descent and natural selection. He is peculiarly struck with its failures to explain the infertility of hybrids and to fill the gap between the invertebrates and the vertebrates. After several years of independent study and investigation of the subject, he has published his conclusion in an elaborate article in the Medical Age that "the vertebrate organism, instead of being a single organism which has been evolved from a simple to its present highly complex form by a gradual and cumulative differentiation, is in fact a compound made up of two distinct organisms constantly associated; . . . that the divergence of the vertebrates from the