—The nails are a peculiar modification of the epidermis and have the same cellular structure as that of the epidermis. The nails are found on the dorsal surface of the fingers and toes and act as a protection, and enable one to pick up small objects, or to grasp more firmly any object. Were it not for the nails it would be impossible for one to pick up a needle from off the floor.
Each nail is convex on its outer surface, and its chief mass which is called the body lies upon the nail bed, or true skin; the free end projects out over the surface of the finger, and is that part which is not attached below, and since it is the continuation of the epidermis, it likewise will have no nerve or blood supply and therefore can be trimmed without pain to the individual.
The root is implanted in a groove in the skin and is composed of cells which have not become horny. The root is white in color and is the little half moon which you can see next to the skin.
The matrix is that part of the true skin beneath the body and the root of the nail, and is so called, because, it is that part from which the nail is produced and so long as the matrix at the root of the nail is uninjured, the nail will be reproduced after an accident.
After death the nail turns black, due to the infiltration of blood into the matrix.
Treatment by the Embalmer.—The blackened condition of the nail due to the infiltration of blood into the matrix can in many cases be overcome by carefully rubbing the nail at the time the body is being injected. After the discoloration is removed the fingers should be kept elevated so that the blood will not settle there again.
The Hair.
—The hair, like the nails, is a peculiar modification of the epidermis and consists of practically the same cellular structure as the epidermis. Hair is found on nearly every part of the body excepting the palms of the hands and the soles of the feet, the borders of the lips, etc. It varies much in length, thickness and in the different races of mankind. In the eyelids it is short, on the scalp it is of considerable length. In other parts as the eye-lashes, the hair of the pubis region, the whiskers and beard the thickness is remarkable.
A hair consists of the root and the shaft. The root of the hair or that part implanted in the skin presents at its extremity a bulbous enlargement, called the hair bulb. Into this bulb we find the small arterial capillary circulating and at its termination the beginning of the venous capillary. In this way the hair is nourished in life. We also find a small nerve going to the hair bulb. The shaft is the remaining part or that part coming out from the skin.
The hair grows from its roots and as it grows it pushes itself out from the skin and owes its growth to the small capillary circulation, carrying pure arterial blood to each and every hair, and for this reason you can understand for yourself the erroneous idea of what is termed the “post-mortem growth of hair.” Only a few weeks ago one of the students declared that he had actually seen a subject shaved and the body at the time of the funeral was placed in a vault to await the arrival of a close relative who had to come from Europe.