Author(s): Thomas A, Rutherford, Hawk PB
Apparently the first authentic observations upon the chemical composition of hair were made by Vauquelin’ and reported in 1806. He found that upon dissolving the hair in superheated steam or in mineral acids a transparent solution resulted which could be precipitated by an infusion of nut galls and which possessed the further property of blackening silver salts. He concluded that hair contained silica, carbonates, iron, manganese, calcium phosphate, and finally a considerable quantity of sulphur. Vauquelin found a lower percentage of sulphur in black hair than was present in white, blond, or red hair. The investigations of v. Laer’ upon the chemical composition of human hair are widely quoted. He could detect no carbonate or manganese in the hair but, like Vauquelin, he found a high sulphur content. v. Laer found the percentage of sulphur in the hair of adult males to vary from 4.63 to 5.44. Kiihne and Chittendenz claim that neurokeratin has a higher content of carbon and hydrogen and a lower content of nitrogen and sulphur than the keratin prepared from the hair of the white rabbit. v. Bibra3 found only 3.83 per cent of sulphur in the hair of a boy ten years old whereas the red hair of a man of thirty contained 8.23 per cent. The same investigator found the average sulphur content of fifteen samples of human hair to be 4.62 per cent. He further found 3.7 per cent of sulphur in the hair of a Peruvian interred four hundred years and 4.4 per cent in the hair of a Bolivian interred one thousand years. As a result of a series of analyses of the hair of different animals v. Bibra determined that 4.25 per cent was the average sulphur content. Mohr4 found the hair of adult females to contain 4.95 per cent of sulphur whereas that of a girl nine years of age contained 5.34 per cent. In the hair of a boy four years old Mohr found 4.9% per cent of sulphur, while the red hair of a boy six years of age contained 5.32 per cent.