The year 1888 may be considered the beginning of a new era in the history of fur dyeing; the commencement of a period which was to see the time-honored, traditional methods of the masters of the art give way to newer methods of an entirely different character; and moreover, the initiation of an age when science with its basis of fact and logic, was to undertake the rationalization of an industry which had hitherto worked upon a more or less irrational, empirical and uncertain comprehension of the fundamental principles involved. It was not the work of a single day, or even of a year which brought about the virtual revolution in the dyeing of furs, but the result of long, patient, systematic effort. About this time, the German coal tar industry was attaining its real stride along the path of progress and achievement, and had already succeeded in reaching, to an appreciable degree at any rate, most users of coloring matters, with the consequence that the natural dyes, with their time and labor-consuming processes of application were gradually being superseded by the new synthetic dyestuffs which could be simply and quickly applied. It was now the turn of the fur dyeing industry to receive the attention of the scientists and technologists responsible for the growth of the coal tar dye industry, and so there appeared in the above-mentioned year, the following patents, taken out by a German chemist named Erdmann: D. R. P. 47349 A Process for Dyeing Hair and Feathers If white hair or feathers are soaked in an aqueous or alcoholic solution of para-phenylene-diamine, and then exposed to the slow oxidation of the air, or are treated in a second solution with some oxidizing agent, then the hair or feathers will be dyed. According to the oxidizing agent chosen, and the concentration of the solution used, the color obtained will be light or dark, varying from the palest blond to the deepest blue-black. Particularly suitable as oxidizing substances are ferric chloride, permanganates, chlorates, hypochlorites, bichromates, and hydrogen peroxide. The dyeings are fast, that is, they do not come off, and the color cannot be removed by washing. Following examples may serve to make the process clear: 20 grams pure para-phenylene-diamine and 14 grams caustic soda are dissolved in a liter of water. The hair, previously degreased, is soaked thoroughly in this solution, and while moist is entered into a three per cent solution of peroxide of hydrogen. The action is not instantaneous, but after a day, the hair is dyed a dark shade; by repetition of these operations a blue-black is obtained.