72 COSMETICS. 



ever, has not been demonstrated. The diverse colour of vari- 

 ous heads of hair is referable, as we have seen, to the presence 

 of special colouring matters. Hence it follows that if such 

 colouring-matters be absent, the remaining hair is white. 

 Narrations abound of the hair having turned white suddenly 

 after some shock, or fright, or other violent mental emotion. 

 No satisfactory explanation of this has ever been offered, and 

 some physiologists deny the fact wholly. Among the number 

 of these must be mentioned Dr. Davy, who, some years ago 

 (1861), read a paper on the subject at the British Association. 

 It is his opinion that hair never turns gray save under the 

 influence of impaired health, or of age. Much study is popu- 

 larly considered to turn the hair gray, and long-continued 

 anxiety. The imputation is doubtless true; but then the 

 immediate cause of grayness may still be impaired health. 



Haller, in his Elementa Pliysiologice, discusses the evid- 

 ence for and against the sudden change of hair to gray exhaus- 

 tively. He refers to eight authorities for proof of such change, 

 but, finally summing up the evidence on behalf of himself, he 

 comes to the same conclusion as Dr. Davy. Those who adopt 

 the popular opinion fortify their argument by referring to 

 the colour-mutations certain animals and birds undergo with 

 change of season. Mountain-hares and ermines, ex. gr., ac- 

 quire white fur towards winter. In like manner so do lem- 

 mings. Mr. Blyth the naturalist examined a lemming that 

 was just undergoing this change, and satisfied himself that 

 the whiteness was referable to special new hairs, not to defect 

 in colouring-matter of the hairs previously growing. For my 

 own part, I confess to a leaning towards the popular belief. 

 If the sudden change of hair from dark to gray be not a fact, 

 I am at a loss to account for the belief to the contrary, which 

 is almost universal; finding expression in the traditions and 

 the poetry of so many nations. Of far higher value than any 

 expression of credence on my part is the testimony of the 

 celebrated skin and hair physiologist and practitioner, Mr. 



