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same in the nostrils of man and the lower animals, in the auditory 

 passage, and in the external ear. We have them again radiating from 

 a circle in those cases where they occur round the nipple in man or 

 woman, and when they surround the orifices of the vulva and the anus. 

 In the extremities, the hair also radiates from a centre, but this can 

 scarcely be classed as an exception ; for as all point downwards, they 

 may fairly be said to be directed from the head. In the human eyebrow 

 we have the hairs arranged on a peculiar plan. Between them, and at 

 the root of the nose, a few central hairs may be seen pointing directly 

 forwards ; above these a few point upwards, below them a few point 

 downwards ; on each side they all diverge outwardly. The centre point, 

 then, may be considered to resemble in some respects the "star" on 

 the forehead of the horse, &c. 



When the hair is long, it can be forced to a great extent to lie in any 

 direction ; when shortened, the natural tendency is resumed. 



It is unnecessary to dwell at length upon the supposed power that 

 exists in some animals to alter voluntarily and temporarily the direction 

 of their liairs. This is done, not by the roots, or by any part of them, 

 but by the muscular fibres, which lie in close contact with them, at the 

 under surface of the skin. It is therefore only to be seen in those 

 creatures which have a cutaneous muscle. This change is best seen in 

 l)irds, where long quilled feathers take the place of hairs. The erection 

 of the head feathers by the occipito frontalis muscle, in many of the 

 parrot tribe, will be familiar to all. Amongst mammals, the porcupine 

 gives us the best example of this power. The human hair cannot 

 undergo any material change of direction ; each particular hair cannot 

 really stand on end like porcupine's quills ; they are not influenced by 

 any direct muscle, and can only be moved by contraction or distension 

 of the skin, &c. In the scrotum, the direction of each hair changes as 

 the cellular tissue relaxes or wrinkles up. 



Some recent anatomists have attempted to demonstrate the existence 

 of muscular fibre in the skin itself. If this be so, there will of course 

 exist the power of changing the direction of liairs, independently of the 

 voluntary sub-cutaneous muscle to which the power has usually been 

 referred.* 



• While these sheets have been going through the press, I have had my attention called 

 to a paper respecting the muscularity of the skin, by Dr. Lister, in tlie Microscopic Journal. 

 He has ascertmned that there are minute muscles connected with each hair — that these 

 muscles are usually of the unslriped variety, but that they are striped or vulnntary at the 

 root of the whiskers of cats, &c. I have seen the structures described, but doubt whether 

 they deserve the name of muscles, except in the last case. But I have no doubt they are 

 eontractile, and can change the direction of hairs. 

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