THE HAIE. 81 



years of age/ says Kobinson, in his Essays on Natural Econo- 

 my, 'supported a weight of 7812 grains; one from a man 

 aged twenty-two, 14,285 grains; and the hair of a man of 

 fifty-seven, 22,222 grains. Muschenbroeck found that a 

 human hair, fifty-seven times thicker than a silk-worm's 

 thread, would support a weight of 2069 grains, and a horse- 

 hair, seven times thicker, 7970 grains ; a part of this extra- 

 ordinary strength is undoubtedly due to the high degree of 

 elasticity which it possesses. Weber found a hair ten inches 

 long stretch to thirteen inches ; and a hair stretched one-fifth 

 returns to one-seventeenth of its original length.'" 



The hair is found occasionally to change or lose colour 

 with great rapidity, and the cause of this has always remained 

 a matter of mystery. Mr Erasmus Wilson says, "I am 

 little disposed to speculate on the modus operandi of this 

 change of colour of the hair, but am content, for the present, 

 to give a fitting place to the fact as it stands. The pheno- 

 menon may be the result of electrical action; it may be the 

 consequence of a chemical alteration wrought in the very 

 blood itself; or it may be a conversion for which the tissue 

 of the hair is chiefly responsible. In any case, the following 

 explanation, offered by an eminent French chemist, Vauque- 

 lin, I should feel inclined to discard, as partaking too largely 

 of the coarser operations of the laboratory. ' We must sup- 

 pose/ says the author in question, ' to explain the sudden 

 change of the hair, that at the critical moment when Nature 

 is in revolution, and when, consequently, the natural func- 

 tions are suspended or changed in nature, that an agent is 

 developed in the animal economy, and passing into the hair, 

 decomposes the colouring matter. This agent must be an 

 acid/ 



"The rapid blanching of the hair derives an important 

 illustration from the animal kingdom. Several of the ani- 



VOL II. 2 Z 



