264 THE SOLIDS. 



Henle * makes the interesting statement, that the curling 

 of hair depends upon its form, and that the flatter the hair, 

 the more it curls, the flat sides being directed exactly 

 towards the curve described. From this it follows, that the 

 hair of Negroes would exhibit in a very marked manner this 

 flattened form. 



SIZE OF HAIRS. 



Hairs differ remarkably in size, both as regards length 

 and breadth : they differ not merely in different individuals, 

 in different localities in the same person, but also in any one 

 given situation, as the scalp or pubis. 



The hairs of the scalp are the longest ; those of the scalp 

 of women are many times longer than those of the same part 

 in man, and according to the measurements of Mr. Wilson, 

 they are also thicker. Next in length come the hairs of the 

 chin of man. Amongst women, instances have been known 

 of the hair extending from the scalp to below the feet, and 

 the beard of man not unfrequently reaches to the waist. 



The shortest and smallest hairs are those covering the 

 general surface of the body, and which are reduced to 

 mere down (lanugo). 



The thickest hairs of the body are those of the whiskers, 

 chin, pubis, and axillae, the finest those distributed over the 

 general surface; the hairs of the scalp are of intermediate 

 diameter. 



The hairs of children are finer than those of adults, and 

 those of the head of men than those of women. 



It cannot be doubted but that frequent cutting and 

 shaving of the hair tends to increase its thickness. 



STRUCTURE OF HAIR. 



Each hair admits of division into two parts, the root and 

 stem, and each of these, again, allows of still further sub- 



* Anat. Gen., vol. vi. p. 314. 



