Although the health, vigour, and beauty of the hair depend largely upon careful and constant attention to its needs, its physiology has, until recently, been very imperfectly understood.
The growth and structure of the hair form a most interesting study. Each hair consists of a root and shaft. The former is situated in the skin, the latter projects from it. The hair-sac, or depression in the skin from which the hair grows, consists of two layers, the inner layer being cellular and epidermic, and the outer layer fibrous.
Within this sac the hair takes root, forming at its lower end a bulb. At the bottom of the hair-sac, or follicle, there is a little projection called the papilla, supplied with blood-vessels and nerves, which enters the hair-bulb and forms, really, the germ of the hair.
The hair therefore grows entirely from the root, from this minute papilla. The hair itself is of fibrous substance. Outside it has a thin, scaly surface (termed the hair-cuticle), and in the centre is the core, or medulla. The outside surface consists of minute flat scales, which overlap each other somewhat after the manner of roof-tiles. This explains the well-known phenomenon of the hair feeling rough when drawn between the fingers in one direction, and smooth when drawn in the opposite direction. The medullary substance of the hair is a kind of pith composed of loosely formed cells and air-spaces. These air-spaces, however, though numerous in white hairs, are almost entirely absent in black hairs.
Nutriment, gloss, and pliancy are furnished to each hair by means of sebaceous oil-glands situated on each side of the hair-bulb, which secrete a greasy fluid. The oily matter which is formed in the sebaceous gland is discharged into the hair-follicle, and thus upon the surface of the hair. Some of the secretion extends over the skin, making it soft, and thus preventing it from becoming hard and dry.
Another interesting fact may be noted in connection with the structure of the hair. Minute muscles, consisting of slender bands of contractile tissue, are fastened to the lower part of the hair-sac, and extend obliquely upwards. The muscle is arranged at an acute angle, so that when it contracts it pulls on the base of the hair-sac. These muscles are not controlled by the will, but are brought into play by various emotions, such as fear or horror, or by shock caused by sudden cold. This explains the condition known as " goose skin " and sudden erection of the hair. In animals these muscles are more active than in human beings.
B. Bulb of hair C Shaft of hair
F. Globular bulbs of perspiratory apparatus
G. Openings of these tubes on the skin called pores
It is not, however, suggested that, in order to maintain cleanliness, the head should be constantly washed. Too frequent washing of the head is not advisable, as too much of the natural oil is thus removed, and, under the constant action of water, the bulb which is at the extremity of the hair-root swells, and the hair becomes lifeless, dry, easily broken, and falls out.
Once a month, therefore, is often enough to wash the head. In the meantime, both scalp and hair can be kept clean and healthy by the daily action of the brush. This should not be too hard, and should have moderately long bristles. The brush will have a stimulating tonic action upon the skin, and a cleansing effect not only upon the scalp, but upon the hair itself, because it will help to free it from the dust and dirt of the atmosphere. The hair, therefore, should be well brushed night and morning, and, if possible, once during the day.
Strong soaps, soda, or cheap shampoo •powders, containing injurious substances, should not be used for washing the head. All these things have an irritating effect upon the scalp. They certainly cleanse the hair for the time being, leaving it very dry and generally fluffy in appearance for three or four days. A strong reaction of the skin then sets in, and the hair frequently becomes exceedingly greasy, moist, and lax. Gradually the hair loses its vitality, and begins to fall.
The best shampoo that can be used for cleansing the scalp and keeping the hair in good condition is the yolk of an egg. When the hair is thick, more than one yolk of egg will be required. The yolks of two eggs should be beaten up with a little hot water and a few drops of liquid ammonia may then be added.
After wetting the head thoroughly with hot, soft water, the yolk-of-egg mixture may be rubbed well into the scalp.
Finally rinse the hair again and again with clear, tepid, soft water until all trace of the egg shampoo has disappeared; dry thoroughly, and brush for ten minutes with a perfectly clean brush.
One of the secrets of keeping the hair in a healthy condition is to make a point of perfect cleanliness with regard to the hair brush. This should be washed at least once a week, and never with hot water or soap, or the bristles will become very soft and yellow.
After freeing the brush from hair, dip the bristles up and down in the ammonia solution, taking care not to immerse the back of the brush in the process, and continue until the bristles look perfectly clean and white. Then proceed in the same way with the brush in the pan of clear water, so that the ammonia is rinsed away. Shake the brush well, and set it on a rack to dry.
Hair oils and pomatums have gone out of fashion, and it is certainly a good thing that they have been discouraged, as the continual application of them has the effect of choking up the pores, and leaving an unpleasant resinous substance on the scalp, which may become rancid, and which is uncleanly and irritating. When the scalp, however, is of an unusually dry nature, and the hair exceedingly brittle, the occasional use of an emollient preparation is sometimes advisable.
Curling and crimping the hair by means of hot irons should be discouraged. The intense heat is exceedingly harmful to the hair, and the irons also pull and break it. The heat abstracts the natural moisture, and causes the hair to become brittle, dry, and to break off.
There are so many methods of curling the hair other than by the use of hot irons, that the employment of curling-tongs is by no means a necessity, even when the fashion demands waves, curls, puffs, or ringlets.
The following are good firms for supplying materials mentioned in thi5 section: The Misses Allen Brown, F.r.h.s. (Scented Baskets); Messrs. Thomas Belvoir & Co. (Toilet Preparations); Edwards Harlene Co. (Hair Tonic); Icilma Co., Ltd. (Toilet Preparations); Oatine Co. (Toilet Preparations); A. & F. Pears, Ltd. (Soap); Potter & Clarke (Asthma Cure); Mrs. Pomeroy, Ltd. (Beauty Specialist); Messrs. The Royal Worcester Corset Co. (Kidfitting Corsets); Whelpton & Son (Pills); Wright, Layman & Umney, Ltd. (Coal Tar Soap).
Pith of human hair, showing its composition of cells
Highly magnified hair, showing the cells overlapping each other