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Page:Popular Science Monthly Volume 56.djvu/300

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POPULAR SCIENCE MONTHLY.

driven to the conclusion that one of the most important results of the evolutionary change has been the gradual increase and perfection of heredity as a function of organisms and a gradual elimination of variability. This view, if it can be established, is of the utmost importance to our theoretical conception of evolution, because it enables us to bring our requirements as to time within the limits granted by the physicists.


MINOR PARAGRAPHS.

Of the archæology of Block Island, Arthur Hollick found in his explorations that around the shores of Great Salt Pond and on the sand dunes that border the western shores of the island evidences of former occupation by the Indians are numerous. Kitchen middens are exposed in several street cuttings, implements are often found scattered over the surface of the ground in certain localities, and skeletons have been unearthed from time to time. In many places the kitchen midden accumulations were so obvious that it was impossible to ignore them entirely. They were found to consist of the customary collection of oyster and other shells, bones, pottery fragments, fire-cracked stones, charcoal, finished implements, rejects, flakes, chips, etc. The finished implements found were two axes, of a plagioclase igneous rock, and three arrow points, all of quartzite. In the sand dunes were many old fireplaces, mostly buried by the sand which has drifted over them. They could generally be located by the richness of the turf on the surface immediately above. Mixed with the accumulations in these places were the bones and teeth of animals. The island promises a good reward for archæological investigation.

In a form of disease known as peckiness in the cypress and pin-rot in the librocedrus, described by Hermann von Schrenk in a thesis presented to Washington University, the wood is destroyed in localized areas, which are surrounded by apparently sound wood. The cell walls are changed into compounds, which diffuse through the walls and fill the cells surrounding the decayed center, and these have been called humus compounds. In both trees a fungus mycelium occurs, with strongly marked characteristics, which flourishes within the diseased centers, and grows between them without affecting the intervening wood. This wood can be utilized for many purposes even when much rotted, and in neither case does the mycelium grow after the tree has once been cut down. The two trees thus diseased, both representatives of a race of trees the majority of which are extinct, are closely related genetically, although growing in different parts of the country. The two forms of decay differ but slightly, and not more than might be expected in two woods of different character.

Mr. J. C. Arthur, of the Purdue University Agricultural Experiment Station, a few years ago picked up a small white flower (Cerastium arvense oblongifolium) growing unobtrusively among the grass and low weeds of the roadside. It was a little more attractive than its relative which is called the field chickweed, and the author suggests the name of starry grasswort for it. Under cultivation it spread out over the ground in a close mat of foliage in a manner characteristic of many members of the pink family, to which it belongs; and now for six weeks in April and May it is a mass of "dazzling whiteness, softened with the pale green of stems and leaves," while "all winter long the prostrate stems remain alive to their very tips, and the leaves maintain a summerlike appearance," without the indurated, polished look so usually associated with evergreen foliage. This is one roadside flower taken up, perhaps casually, for cultivation and improvement. There are others—no one knows how many—that will doubtless likewise reward the pains taken with them; and this inspires Mr. Arthur to suggest to others that they keep a lookout for plants that may become desirable garden varieties and try them. "It is evident that showiness in the wild state is not the most important criterion by which to gauge the future culture value of a plant. One needs to have many factors in mind to meet with success, and it is hoped that the