118 MAMMALIA. 



The pigment is best examined in hairs moistened 

 with a little spirit of wine, which displaces the air 

 from the cells of the pith, and renders the hair trans- 

 parent ; a little water should be subsequently added. 

 The cuticular scales are also well shown by this pro- 

 ceeding. Towards the root of the hairs in the mouse, 

 they project beyond the margin, giving it a toothed 

 or dentate appearance; in the hair of the mole, 

 the bat (fig. 5), or the wolf, this dentation may 

 also be seen. In the hairs of some of the foreign 

 bats, the scales are whorled, forming very beautiful 

 objects. 



The cells of the pith (PI. IX. fig. 7) also present 

 interesting varieties, being sometimes arranged in a 

 single row, at others in two or more rows (fig. 6). 

 These are best seen in hairs recently immersed in 

 spirit or in oil of turpentine ; for if the hair be too 

 long soaked in these liquids, the air will be entirely 

 displaced by them. The cells of the pith appear black 

 by transmitted and white by reflected light, in the 

 dry hairs, from the presence of air. They may be 

 well examined in the hair of the mouse (figs. 6 & 7), 

 or in that of the mole. Wool, which is the hair of the 

 sheep, consists of curled fibres (PL IX. fig. 10), in 

 which the imbricated arrangement of the surface- 

 scales is very distinctly seen. 



In PL IX. figs. 10-13 the fibres of wool, flax or 

 woody fibre, cotton, and silk are represented together, 

 to allow of comparison ; for the microscope is of great 

 assistance in discriminating these substances when 

 existing in textile fabrics. The fibres of wool (fig. 10) 

 are distinguished by their solidity, wavyness, and 

 the imbricated scales ; those of flax (fig. 11) by their 

 thick walls, great length, acute ends, and their knotty 

 appearance at intervals. The fibres of cotton (fig. 12) 

 are soft, flaccid, flattened, and often twisted; and 

 those of silk (fig. 13) are solid and very slender. By 

 a little chemical testing, the discrimination is made 



