NUMBERED THE HAIRS OF THE HEAD.

New Zealand Graphic, Volume XVII, Issue XVIII, 31 October 1896, Page 567

NUMBERED THE HAIRS OF THE HEAD.

There are 334,000 hairs on the human body. Professor Charles Stewart, who deposed to this at the Royal Institution recently, has counted them, so says the London Graphic. He would not, of course, be particular to a hair or two one way or the other, but this on tbe average is the result. The skin has, therefore, a very respectable family of offsprings, for tbe biologists can show us beyond all doubt that hairs are, after all, only special parts of the skin that nature has modified in this way in order to better protect and keep warm her highly important works within. The human skin is a much more complex sort of fabric than is popularly supposed. The true skin is right underneath. Yon can make its acquaintance with tbe aid of a file or the sharp corner of a door lock. The outer skin, or cuticle, is really a continually renewed shield of horny scales, which are the cast-off dead cells of the living layer below. The under skin is the real business article, full of cunning little ‘touch nerves,’ blood vessels, lymphatics, sweat glands, fat glands, hair follicles and what not. The follicles are the pits in which the hairs are grown, something like celery, and nature has expended apparently a quite ridiculous amount of care on these structures. The hair in each cell is a direct growth of the skin. It grows at the rate of half an inch a month. The colouring matter, as we know, is apt to fade and leave us at the mercy of those who compound fluids which ‘are not dyes.’ Professor Stewart thinks it quite possible that sudden fright may blanch the pigment •in a single night,’ but how it is done, since this pigment in most cases is far away from any nervous control, he fails to see. Some people have a peculiar sparkling look about their sandy hair. The professor traces this to alterations of white and coloured growth, which he finds correspond with alternate periods of twelve hours’ normal growth. The pigment is, perhaps, not deposited during the night, but is during the day, or vice versa. * Each particular hair ’ stands up * like quills upon the fretful porcupine ’ (which, by the way, are also hairs) by virtue of an erector muscle, one end of which is fastened to tbe bulb of the hair and the other to the point near the surface of the skin. When the muscle contracts under nervous excitement the hair is pulled up vertically (it usually lies a little slantingwise). The * pull ’ on the muscle is also seen at the point of attachment to the skin, giving rise to the little pimples, which, in conjunction with the erect hair, produce the appearance known as ‘goose flesh.’ Other children of the skin, but only twenty in number, are the nails. These arise out of sharp folds in the skin, and are essentially very tough, horny material, built up from the living skin cells, much in the same way as hairs are built up. The growth is at the rate of about the thirtysecondth of an inch a week. Tbe nail is fastened to the under skin by a peculiar system of locking teeth. While talking about the skin Professor Stewart did not overlook the ‘sweat glands,’ which lie buried in the under skin, extracting from the blood some fifty ounces of watery waste products a day. These pass out through corkscrew passages in the outer skin, emerging in the shape of the myriad little pores, which we can just make out by the aid of an ordinary pocket lens. There are about 76,000 of such openings on tbe palm of one’s hand. Professor Stewart has counted them, but again he will not risk his reputation for strict veracity on the question of a single pore one way or another. It is averages he deals in, feeling, of course, that the public are not exacting in such matters.