

MICROSCOPE IN-DOOU3. g^ 



scope, the pulpy portions will present a dark ap- 

 pearance in the centre, as seen at a. The hairs of 

 animals offer a great variety in the disposition of 

 the cells of which they are composed. The hairs 

 of the mouse present a series of dark partitions 

 running across the hair between the cells. In the 

 younger hairs, these partitions are single, as repre- 

 sented at a in figure 185, plate 7 ; whilst in the 

 older ones they appear double, as seen at b. The 

 hairs from the ear of the mouse present these dark 

 partitions very distinctly, shown at d. Such hairs 

 stand intermediate between true hair, a section of 

 which is seen at c, and wool. A piece of flannel or 

 blanket will afford a good illustration of the latter. 

 This is figured at 235 in the 8th plate. In this 

 case it will be seen that the scales, or cells, of the 

 cortical part, project beyond the surface, and render 

 the wool rough. This roughness of the outside is 

 supposed to render such hairs fitted to be used in 

 the process of felting ; the rough sides of the hairs 

 adhering together. The chemical composition of 

 the hair has also something to do with this pro- 

 cess. Human and other smooth hairs, will not 

 felt. 



The fibres of plants used in weaving may be 

 conveniently compared with hairs derived from the 

 animal kingdom. The woody fibre of the flax may 

 be obtained from a linen handkerchief. A linen 

 fibre is represented at b in figure 234, plate 8. 

 The apparent knots in the fibre arise from injury 

 in the uses to which the fabric has been applied. 

 The original fibres have no such fractures, as shown 

 at a, and are perfectly smooth. So are the fibres 

 of silk, represented at figure 236. Cotton-wool is 

 produced from the inner surface of the pod, or fruit 

 of the cotton-plant, and is figured at figure 237. It 

 becomes twisted during its growth, and although 

 a 



