Page:Popular Science Monthly Volume 42.djvu/883

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throw the salt over the left shoulder three mystic times and discomfit the wicked one exceedingly. It is interesting to view the grave solemnity with which the intelligent and well-educated woman of to-day will perform that ceremony."


Rock Striation by River Ice.—A study of the striation of rocks by river ice has been made by Mr. J. E. Todd in the Mississippi and other Western rivers. While not much attention has been paid to this agency, the author finds that planation and striation are sometimes the work of river ice armed with erratics; that the situations most favorable for the phenomenon seem to be on the outside of a bend, or near a strong current, near low-water mark, and below a point where siliceous erratics lie near the water-level. The dynamical conditions necessary are probably a sudden breaking up of the ice before it is rotted by thawing and a flood to wield it. The proper conditions do not often occur in our present Western streams. Usually the striæ are parallel, as much so as in glacial action, and commonly on surfaces dipping up stream, but occasionally upon limited areas dipping down stream. While these facts, the author observes, may have no direct significance of practical value, they indirectly throw much light upon the possible origin of the extra-morainic drift and of some ancient striated surfaces outside of the moraines.


Animals not Afraid of Man.—Mr. W. H. Hudson's observations of birds in La Plata lead him to different conclusions from those which Darwin and Herbert Spencer have reached respecting their supposed instinctive fear of man or birds of prey antecedent to experience or parental teaching. The one thing that is instinctive, says Mr. Alfred R. Wallace, in his review of the book, "is the alarm caused by the warning note of the parent. This produces an effect even before the chick is hatched, for in three different species belonging to widely separated orders Mr. Hudson has watched the nest while the young bird was chipping its way out of the egg and uttering its feeble peep, when, on hearing the warning cry of the mother bird, both sounds instantly ceased, and the chick remained quiescent in the shell for a long time, or till the parent's changed note showed that the danger was over. Young nestling birds take their food as readily from man as from their parents till they hear the warning cry, when they immediately close their mouths and crouch down frightened in the nest. Parasitical birds, which do not recognize the warning cries of their foster-parents, show no fear. The young parasitical cowbird takes food from man, and exhibits no fear, although the foster-parents are hovering close by, screaming their alarm notes, So a young wild dove, reared from the egg by domestic pigeons, which, never being fed, were half wild in their habits, never acquired the wildness of his foster-parents, but became perfectly tame and showed no more fear of a man than of a horse. He had none of his own kind to learn from, and did not understand either the voices or the actions of the dove-pigeons. Mr. Hudson has also reared plovers, tinamous, coots, and many other wild birds from eggs hatched by fowls, and found them all quite incapable of distinguishing friend from foe, while some, such as the rhea and the crested screamer, are much tamer when young than domestic chickens and ducklings. Mr. Hudson concludes that birds learn to distinguish their enemies, first, from parental warnings, and later by personal experience.


The Truffle.—In a book on that vegetable, lately published in France, M. Ad. Chatin defines the truffle as a mushroom, which is not a parasite, though it grows by preference in the immediate vicinity of certain kinds of trees; and like its congeners, the tuberaceous mushrooms, instead of living in the air it is hypogeous. The truffle is first mentioned by Theophrastus, who calls it mizy and mison, and regards it as a rootless plant engendered by the thundershowers of autumn, but capable, according to many observers, of reproducing itself from seeds brought by storms from Tiaris, on the shores of Mitylene. This truffle, that of Lesbos, was an inferior variety to the truffle of Périgord, which is so highly prized by epicures. The truffles of Algeria, called terfas, and those of western Asia, called kamés, although not equal to those of France, are of considerable importance as food to the Arabs. M. Chatin has added several species, previ-