128 SENSE OF TOUCH. 



The colour of the hair is different in different races and individuals. 

 By some, this is considered to depend upon the fluids contained in the 

 pith. M. Vauquelin 1 analyzed the hair attentively, and found it to con- 

 sist chiefly of an animal matter, united to a portion of oil, which appeared 

 to contribute to its flexibility and cohesion. Besides this, there is another 

 substance, of an oily nature, from which he considers the colour of the 

 hair is derived. The animal matter, according to that chemist, is a 

 species of mucus; but other chemists believe it to be chiefly albumen. 

 Vauquelin found, that the colouring matter is destroyed by acids ; and 

 he suggests, that when it has suddenly changed colour and become gray, 

 in consequence of any mental agitation, this may be owing to the pro- 

 duction of an acid in the system, which acts upon the colouring matter. 

 The explanation is hypothetical, and is considered, and characterized 

 as such by Dr. Bostock; but it must be admitted, that the same objec- 

 tion applies to the view he has substituted for it. He conceives it 

 "more probable that the effect depends upon a sudden stagnation in 

 the vessels, which secrete the colouring matter; while the absorbents 

 continue to act, and remove that which already exists." There is, how- 

 ever, no more real evidence of "stagnation of vessels" than there is of 

 the formation of an acid. Our knowledge is limited to the fact, that 

 a sudden and decided change in the whole pileous system may occur 

 after great or prolonged mental agitation. 



" My hair is gray, but not with years, 

 Nor grew it white in a single night, 

 As men's have grown from sudden fears." 



Byron's "Prisoner of Chillon." 



" Danger, long travail, want and wo, 

 Soon change the form that best we know : 

 For deadly fear can time outgo, 



And blanch at once the hair. 

 Hard toil can roughen form and face, 

 And want can quench the eye's bright grace, 

 Nor does old age a wrinkle trace 



More deeply than despair." 



Scott's " Marmion. r * 



It is stated by M. Be Lamartine, 3 that such a change occurred in a 

 single night to the queen of Louis the 16th the unfortunate Marie 

 Antoinette when the royal party was arrested at Yarennes, in 1791. 



But a similar, though more gradual change, is produced by age. We 

 find some persons entirely gray at a very early period of life ; and, in 

 old age, the change happens universally. It is not then diflicult to 

 suppose, that some alteration in the nutrition of the hair may super- 

 vene, resembling that which occurs in the progress of life. Dr. Bostock 

 doubts the fact of such sudden conversions ; but the instances are too 

 numerous for us to consider them entirely fabulous. Still, it is difficult 

 to comprehend how parts, which, like the extremities of the hair, are 



1 Annales de Chimie, torn. Iviii. p. 41, Paris, 1806. 



3 For many such cases see M. E. Wilson, a Practical Treatise on Healthy Skin, p. 95. 

 London, 1845. 



3 "La reine ne dormit pas. Toutes ses passions, de femme, de mere, de reine, la colere, 

 la tevreur, la desespoir, se livrerent un tel assaut dans son ame, que ses cheveux, blonds la 

 vieille, furent blancs le lendemain." Histoire des Girondins, i. 116. Paris, 1847. 



