The undertakers' manual

by Auguste Renouard

Saline, and Extractive Constituents of the Tissues.—We find in all the animal tissues small quantities of a great variety of salts, the same as those which will be hereafter noticed as existing in the blood, to the presence of which in the substance of the tissues they are probably due. In the tissue of the bones and teeth, however, these saline matters are deposited in much greater quantities, and in disease and old age bony deposits occur in all those tissues, which yield true gelatine on boiling. The composition of the bones will be hereafter noticed.

Of the Composition of the Tissues and of the Secretions in Health and Disease.—Having described thus individually the constituents of the tissues, we shall now present such results as have been hitherto obtained as to the quantitative composition of the organized tissues formed by their reunion, their secretory products and morbid alterations.

The skin of animals is a congeries of finely constructed organs, sensitive and secretory, imbedded in a peculiar tissue, which is one of those most yielding gelatine, whence the process of tanning skins. On the surface of the skin there is secreted a substance, which, though varying in anatomical structure and appearance exceedingly, as it forms the fine epidermis, the nails, the hair, etc., is yet throughout all their shapes identical in chemical character, and may be described as the same substance. The principal mass of hair is composed of the same substance as horn, but the color is due to an oil which may be extracted by ether. If by virtue of the sulphur contained in hair a solution of litharge in some limestone water blackens it, a solution of nitrate of silver will also blacken the hair, but by a deposition of the metal.

The perspiration from the skin varies in nature according to the part of the body; it is generally acid, contains traces of albumen, fatty matter and the salts of the blood; it often contains, also, an odoriferous, volatile principle, characteristic of the animal by which it is secreted.

Cellular and Serous Tissues.—These tissues are constituted of gelatinous materials similar to that in the skin, and hence dissolve by boiling water, being converted into gelatine. In the natural condition of these membranes their surface is moistened by a watery liquid, which, accumulating in excessive quantity, gives rise to the dropsies of the cavities, or of the cellular tissues. This serum of the cavities is clear and colorless. The cells of the cellular tissues, in which fat is usually deposited, are often filled up by an albuminous material having considerable analogy with casein; it is thus that the diffused hardening of the cellular tissue and the local white tumors have their origin.

Of the Muscular Tissue.—From what has been already said of fibrine, it is evidently the essential element of the muscular tissues, and forms with water almost the whole of their parts.

Of the Bones.—In vertebrated animals with osseous skeletons the earthy material, in all cases, consists principally of phosphate of lime, with phosphate of magnesia, carbonate of lime and soda. By digesting a bone in dilute muriatic acid, all of these inorganic salts are removed, and the cartilage remains, preserving perfectly the form of the bone.

The teeth present, in their combinations, the greatest analogy to bone; the principal and organized substance of the teeth is indeed true bone, containing indeed less cartilage and more phosphate of lime than other bones. The enamel, which is an inorganic secretion from the surface of the long tooth, is almost destitute of any animal matter.

Of the Composition of the Blood.—Blood is, in the higher classes of animals, an opaque, thick, red fluid; it has a salty and nauseous taste, and a peculiar smell, resembling that of the animal whence it has been derived.

When the blood of any red blooded animal is allowed to rest, it gradually forms a soft jelly, from which, after some time, a thin yellowish fluid (serum) separates, while the red jelly or coagulum contracts in volume and acquires great consistence. If this coagulation of the blood takes place slowly, the upper portion of the coagulum becomes white or pale yellow; forming thus, the buffy coat. There is no doubt that the blood, while in connection with the animal, participates in its life, and the phenomena of coagulation are to be referred to a new arrangement of its materials consequent on the loss of that vitality.