544 



THE MICROSCOPE. 



from dark-coloured hairs have colouring-matter deposited 

 on them in small patches. In some cases they appear to 

 terminate in a pointed process, like the quill part of but- 

 terflies' scales; and in others the free margin is serrated. 



By scraping, many of them 

 will be detached separately; 

 but in some few cases, as many 

 as four or five will be found 

 joined together : in the larger 

 hairs, the cellular structure 

 of the interior, as well as the 



Fig. 279. Transverse section of Hair fibrOUS character of the shaft, 

 c{llularstr S ucture g "* fibr US "^ ar6 better Seen after the Scales 



have been removed. 



The hair owes the greater part of its colour to pigment- 

 cells: as these decay, and become gradually divested of 

 their colouring-matter, they appear whitened, or "turn 

 grey." These hexagonal cells also give colour to the skin 

 of the negro, and are situated immediately beneath the 

 transparent coat. A small por- 



%~|W ^ ^ on * s snown i n n - ^SO, the 



^ aA ^S ^5^& vacant space denoting the situa- 

 tion of a lost hair. 



Certain parts of the skin and 

 mucous membranes are espe- 

 cially supplied with papillae, 

 which serve as organs of touch ; 

 throughout the greater part of 

 the skin there are papillae more 

 or less sensitive, but only at 

 the extremities of the fingers, 

 lips, and in a few other situa- 

 tions, are these highly de- 

 veloped, as in fig. 281. Pa- 

 pillae are either filiform or tubi- 

 form, and have entering into them nerves and blood- 

 vessels; the former supplying the sensibility of the skin, 

 and terminating in loops, as shown in fig. 283. 



The skin is the seat of two processes in particular; 

 one of which is destined to free the blood from a large 

 quantity of fluid, and the other to draw off a considerable 



Fig. 280. Pigment Cells from 

 the skin. 



