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Show l!JO EXPUES, ION o:n~ ORIEl!': enco in the obliquity of the eyebrows appar~~tly deponded on a difference in their general mobility, and in the strength of the pyramidal muscles. In both these cases the eyebrows and forehea~ were ~cted on und r the influence of a strong light, In premsely tho same 1nanner, in every characteristic detail, as under the influence of grief or anxiety. Duchenne states that the pyramidal muscle of the nose is less under the control of the will than are the other muscles round the eyes. He remarks that the young man who could so we~l act on h.is griefmuscles, as well as on most of his other famal muscles, could not contract the pyramidals.5 This power, however, no doubt differs in different persons. The pyramidal muscle serves to draw down the skin of the forehead between the eyebrows, together with thei1· inner extremities. The central fascire of the frontal are the antagonists of the pyramidal; and if the action of the latter is to be specially checked, these central fascire must be contracted. So that with persons having powerful pyramidal muscles, if there is under the influence of a bright light an unconscious desire to prevent the lowering of the eyebrows, the central fascire of the frontal muscle must be brought into play; and their contraction, if sufficiently strong to overmaster the pyramidals, together with the contraction of the corrugator and orbicular muscles, will act in tho manner just described on the eyebrows and forehead. vVhen children scream or cry out, they contract, as we know, the orbicular, corrugator, and pyramidal muscles, primarily for the sake of compressing theil' eyes, and thus protecting them from being gorged with blood, and secondarily through habit. I there- -- ----- ~ )fecanisme de la Pllys. Humaine, Allmm, p. 15. JIAI'. VII. OBLIQUE EYEBRO,V. '. lDl fore expected to find with children, that when they endeavoured either to pr vent a crying-fit from coming on, or to stop crying, they would check the contraction of the above-named muscles, in the same manner as when looking upwards at a bright light; and consequently that the central fascim of the frontal muscle would often be brought into play. Accordingly, I began 1nysolf to observe children at such times, and asked others, including some medical n1en, to do the same. It is necessary to observe carefully, as the peculiar opposed action of these muscles is not nearly so plain in children, owing to their foreheads not easily wrinkling, as in adults. But- I soon found that the grief-muscles wore very frequently brought into distinct action on the. e occasions. It would be superfluous to give all tho cas s which have been observed; and I wHl specify only a few. A little girl, a year and a half old, was teased by some other children, and before bursting into tears l1er eyebrows became decidedly oblique. vVith an older girl the same obliquity was observed, with tho inner ends of the eyebrows plainly puckered; and at tho same time the corners of the mouth were dra\Yn downwards. As soon as she burst into tearr; the features all changed and this peculiar expression' vanished. Again, after a little boy had been vaccinated, which made hiln scream and cry violently, the surgeon gave him an orange brought for the purpos , and this pleased the child much ; as he stopped crying all the characteristic movements were observed in- dnding the formation of rectangular wrinkles in' the 1niddle of the forehead. Lastly, I met on the road a little girl three or four years old, who had been frightened by a dog, and when I asked her what was the matter, she stopped whi1npcring, and her eyebrows instantly became oblique to an extraordinary degree. |
