Page:Popular Science Monthly Volume 36.djvu/696

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seems to me the neglect of a source of inspiration that one can ill afford to slight. Pursued in the spirit that I have tried to indicate, as a natural extension of the experimental knowledge of childhood, and through the medium of a few substances thoroughly studied, I venture to recommend it quite as highly as a means of culture, as an end valuable in itself. It would be an easy task to extend such considerations indefinitely; but I want rather to open the right door into chemistry, than to decorate its vestibule. "It is a foolish thing," says the author of the Book of Maccabees, "to make a long prologue and to be short in the story itself."


THE muscles of the mouth have a triple function. They serve in the articulation of sounds, and assist the activity of the taste and the hearing. Our present study is limited to the movements of the buccal muscles, which have to do with the taste. Taste is the earliest developed of all our senses, and abides with us from the first to the last hour of life. No other sense controls man so early or with so much power; none remains so long faithful to him.

The lips may be regarded as a flat, circular muscle placed in front of the buccal cavity, cleft horizontally in the middle, with a moist, ruddy mucous membrane covering the edges of the opening thus formed. Not regarding now the muscles of the lower jaw, the mouth is closed by the contraction of the orbicular muscle of the lips, and opened by antagonistic muscles which are fixed on its outer edge. The mouth is, then, destined to undergo very great variations of form; and, by virtue of this variety of its movements, it enjoys at least as much importance as the eyes in whatever concerns the mimetic expression of the countenance.

When any object perceptible to the taste is placed upon the tongue at rest, the sensation of the contact is vague and imperfect. It is only when the upper face of the tongue is pressed against the osseous vault of the palate that a complete impression of the object can be made upon the nerves of taste, the extremities of which abut upon the caliciform papillæ of this surface. Hence, when in mastication we inopportunely encounter anything of disagreeable taste, we at once separate our jaws to get the tongue as far as possible from the palate or to prevent any further rubbing of the upper face of the tongue and repetition of the bad taste. The movement of the jaws is accompanied by a corresponding movement of the mouth. The upper lip is removed