AND PHYSIOLOGY. 



303 



contents into the same pore in 

 which the hair itself is lo- 

 cated. This secretion is an oil 

 which keeps the hair in a 

 smooth and moist state. 



530. Their Number.— The 

 number of the hairs varies 

 with the color and portion of 

 the tody. In one case there 

 were found on the same sur- 

 face 147 black hairs, 162 

 brown, and 182 blonde. On 

 a surface one fourth of an 

 inch square the same author 

 found on the scalp 293 hairs 

 and on the chin 39. 



Layer from Scalp, a, Oil Glands. I> % 



531. Their Distribution Hair c » Follic ^ 

 and Direction— They are 



implanted either singly or in twos or threes, or even four 

 or five together, and their direction is rarely perpendicular 

 to the skin, being, in a natural state, downwards. They may, 

 however, be changed in their direction by persevering efforts, 

 as is sometimes seen by the brushing of the hair away from 

 the forehead. 



532. Chemical Composition — Durability —They differ 

 from most tissues of the body by containing ten per cent, of 

 sulphur. This, together with the fact that they contain a 

 large per cent, of nitrogen, accounts for the unpleasant odor 

 given off while burning. They resist decomposition better 

 than most of the tissues. Those of Egyptian mummies re- 

 main quite unchanged. And it is owing to their durability 

 that they are used as relics of departed friends. 



Fig. 295. 



530. What is said of the number of hairs on the horly ? 531. How are they distributed, 

 and what direction do they take? 532. How do they differ from most other tissues in 

 chemical composition ? How durable is hair ? 



