268 THE SOLIDS. 



off, and in this way their size, form, and structure, may be 

 satisfactorily studied. 



The scales are absent from the points of the finer hairs. 

 In consequence of their imbrication upon each other, their 

 little thickness, and of the double contour presented by their 

 free edges, they frequently cTmvey the appearance rather of 

 anastomosing fibres running round the hair than of distinct 

 scales. 



A hair rolled between the fingers always advances in a 

 given direction, viz. towards the apex : this results in part 

 from the tapering form of the hair, and partly from the more 

 or less spiral disposition of the scales. 



Fibrous Layer. The fibrous portion of the stem of the 

 hair constitutes its chief substance and bulk, forming two- 

 thirds of the entire diameter, one- third on each side of the 

 medulla. In hairs which are not too dark, the constituent 

 fibres may be seen in situ : they are most palpably brought 

 into view either by scraping the hair with a knife or by 

 crushing it after maceration in sulphuric acid : they are also 

 best seen in the larger hairs and near the centre of the shaft. 



Henle describes the fibres as flat, with uneven edges, and is 

 in doubt as to whether they are branched or not. To my 

 observation they appear much smaller than they are stated 

 to be by Henle, and are spherical and simple. (See Plate 

 XXIX.) 



These fibres have a cellular origin, and are formed by the 

 elongation of the inner cells of the bulb in which their gra- 

 dual extension into perfect fibres may be traced. 



They are stated by most observers not to extend to the 

 extreme point of the hair; and the same statement is like- 

 wise made in reference to the medullary canal and cortical 

 scales. Of what, then, it may be fairly asked, is the point of 

 the hair constituted, since every structure entering into the 

 formation of the shaft is denied to it ? The assertion that 

 the fibres do not extend to and form the apex of the hair is 

 evidently erroneous. In the examination of the points of a 

 number of hairs which have not been recently cut, fibres often 



