THE MUSCLES* 59 



when the anterior bellied contract, the scalp is drawn forwards, and 

 when the posterior, it is carried back again. There are many 

 individuals who have no power of moving the scalp in this way. 

 This muscle is part of an apparatus which is very fully developed 

 in many of the lower animals, for wrinkling the skin suddenly, to 

 drive the flies off, as we see a horse do every now and then on a 

 warm day. In them, a thin layer of this kind exists all over the 

 body, but in man it is not needed, as the hands are at his disposal 

 to do the same office more perfectly. Underneath the anterior 

 bellies are two small muscles, not seen in the figure, running from 

 the root of the nose outward under the eyebrow, and fixed to the 

 skin there, which knit the eyebrows, drawing them together. On 

 the side of the head are seen two thin muscles attached to the ex- 

 ternal ear, for drawing it upward and backward. These, like the 

 muscles of the scalp, are rudimentary in the human species, being 

 of use only in those animals whose ears serve them for fly-traps, 

 and can be directed backward or forward to catch sounds coming 

 from either quarter. Those men, however, who have much power 

 over the scalp are generally able to shake the ears, although few 

 of them are aware of it. I have seen Prof. Oliver practise this. 



Passing around the eyelids is an orbicular muscle, which closes 

 them. It will be observed in closing the eye that the upper 

 eyelid only comes to meet the other, while the lower one moves 

 horizontally towards the nose ; having the effect of carrying any 

 particles of dust which may have alighted on the eye towards the 

 nose, whence they are washed out by the tears, or pass down into 

 the nose. That part of the muscle which lies in the thickness of 

 the lids is thin and pale, and is all that acts in the involuntary 

 winking which takes place thousands of times during the day, in 

 order to wipe the surface of the eyes ; while the parts which lie on 

 the forehead, the temple, and the cheek, are brought into action 

 only when the eye is compressed strongly by an exertion of the 

 will. In doing so, it wrinkles up the skin of the face, as is seen 

 in a hearty laugh, when the eyes are half closed. The muscle 

 which raises the upper eyelid is not here seen, for it lies deep 

 within the orbit. 



Another orbicular muscle closes the mouth, and is connected 

 above to the partition of the nose, which it has the power of draw- 

 ing down. It is the antagonist to all the other muscles which eon- 

 verge to the mouth, and according as they resist it in particular 

 directions, it produces all manner of distortions of the mouth. 



