Page:Popular Science Monthly Volume 41.djvu/355

 in its inception can properly bear no wider designation than the "dressing of skins."

Leather, in the broad application of the term, is a combination of gelatin and mineral salts, oil or tannic acid. The hide or skin of an animal consists of two layers—the outer (epidermis), a hard cellular plate into which neither nerves nor blood-vessels penetrate; and the inner, or true skin (dermis), a dense membrane composed of fibers interlacing in a curiously complex manner. These connecting fibers consist almost wholly of gelatigenous tissues. They will dissolve in boiling water, thus forming gelatin, will enter into solution with concentrated acids and alkalies, and will combine with oil and tannin. As such this tissue forms the basis of all leather, and the labor of the tanner becomes one of bringing it into chemical or mechanical combination with these other components.

The original process of curing skins was probably the simple one of cleaning and drying them. Removal of the hair by maceration in water seems to have been common among the very early tribes, and one writer has suggested that the idea was obtained from the natural process of depilation. They must certainly have been familiar with it in the case of drowned animals, where maceration can be plainly observed. Following this, smoke, sour milk, oil, and the brains of the animals themselves were found efficacious. Many of these primitive methods are employed at the present time, thus bringing into novel conjunction the days of the roving Massagetæ and those of the thrifty American. An acquaintance of the writer, a Massachusetts tanner, traveling recently through the province of Winnipeg, chanced upon a small Indian village. The place was in no way interesting except in the employment of the squaws. They were all busily engaged in removing the hair and muscles from the skins, largely those of deer and moose, which the bucks had taken in the chase. This they did by means of sharpened bones which they plied in a vigorous manner, rubbing away both flesh and hair. The skins, it seemed, had been taken from the animals some time before, and together with the brains partially dried in the sun. After the squaws had completed this scraping process, the skins were steeped in a lather-like mixture made from water and dried brains, and were then reduced to a soft texture by frequent