“The skins of the animals are composed of two chief parts: the corium or cutis, and the cuticle or epidermis. The former, which is the true skin, is a tissue of delicate fibres, crossing each other in all directions, more thickly interwoven toward the surface, than in the deeper parts of the skin. It is pervaded by a great number of conical channels, the small extremities of which terminate at the external surface of the skin. These channels, which are placed obliquely, contain nerves, secretory vessels, and cellular membranes. “The cuticle or exterior covering is an insensible horny membrane, composed of several layers of cells, devoid of blood-vessels. “The process of tanning consists in the combination of the gelatinous substance of which the skin is principally composed, and the tonic acid, or tannin. The gelatinous substance in skins, and the tannic acid, having a strong chymical affinity for each other, the hide or skin is converted into leather whenever tannin is brought into contact with the gelatinous tissue or fibre. “The slowness of the process in tanning leather, and the imperfect manner in which it has hitherto been accomplished, arise from the difficulty in bringing the tannin or tannic acid into contact with the gelatinous tissue, or fibre of the skins; and although, of late years, considerable modifications of the old method of tanning have been introduced, chiefly consisting in the employment of new materials, and the application of hydrostatic pressure, yet the result, upon the whole, has been merely to effect a saving of the time consumed in tanning, and a consequent reduction of the price, without any improvement in the quality of the leather, but rather the reverse. This has given rise to a strong prejudice in the minds of persons connected with the leather trade, against leather tanned by any quick process. The difficulty of bringing the tannin, or tannic acid, immediately and effectually into contact with the gelatinous fibre of the skin, arises from several causes, which it may be useful to enumerate. “In preparing the skins and hides for the tanpit, they are steeped for a considerable time in a solution of lime, to remove the hair and epidermis. In this process, the skin imbibes a considerable quantity of lime, which has the effect of either removing from the hide or skin, a portion of the gelatinous substance, in the form of soluble gelatine, or, of altering the gelatinous fibre, so as to render it incapable of speedily and effectually combining with the tannin or tannic acid, and the pores of the skin are so impregnated with lime, as to prevent the tanning principle from operating freely, or reaching the heart of the skins.