These rashes or eruptions are not dangerous in themselves, though often very uncomfortable, but help us to recognize the disease; they probably show us the sort of thing that is going on in the deeper parts of the body. If you imagine that your throat and bronchial tubes and lungs are peppered as full of the disease spots as your skin is, in measles and in scarlet fever, you will readily understand why your throat is so sore and why you have so much tickling and coughing.

The Health of the Scalp and Hair. The scalp, being covered by hair, does not perspire so freely as the rest of the skin of the body; but a considerable amount of oily waste matter is poured out on it, and the surface of its skin scales off in exactly the same way as does the rest of the body. If this accumulation of tiny scales and grease is not properly brushed out, it forms an excellent seed-bed for some of the milder kinds of germs that attack the skin; and a scurfy, itchy condition of the scalp is set up, known as dandruff.

The best way to keep the scalp clean of these accumulations of greasy scales is by vigorous and regular brushing with a moderately stiff, but flexible, bristle brush. Wire brushes should not be used, as the wires scratch and irritate the delicate scalp and do more harm than good. If you watch a groom brushing and currying the coat of a thoroughbred horse, you will get a fair idea of hew you ought to treat your own scalp at least twice a day, night and morning.

If this currying of the hair be thoroughly done, and the head washed with soap and hot water about once a week for short hair and twice a month for long hair, most of the dangers of dandruff and of other infections of the scalp will be avoided. One thing to be remembered is, don't brush too hard or too deep. There is an old saying and a good one, "You can't brush the scalp too little, or the hair too much."

Wetting the hair for the purpose of "slicking" it or combing it, is about as bad a thing as could be done; for the moisture sets up a sort of rancid fermentation in the natural oil of the scalp, giving the well-known sour smell to hair that is combed instead of brushed, and furnishing a splendid soil for germs and bugs of all sorts to breed in. There is no objection to boys' and men's wetting their hair in cold water as often as they wish, provided that they rub it thoroughly dry afterward and give it a brisk currying with the brush.

Hair oils and greases of all sorts are sanitary nuisances, and mere half-civilized and lazy substitutes for proper brushing and washing. There is no drug known to medicine which will cause hair to grow, or make it thicker or curlier. All "hair tonics" claiming to do this are frauds.

Corns, Calluses, and Warts. Our skin not only made our hair, teeth, and nails, but still retains in every part a trace of its nail-making powers, so that under pressure or irritation, it can thicken up into a heavy leather-like substance which we call callus. This is naturally and healthfully present in the soles of the feet and the palms of the hands. Savage, or barbarous, races who wear no shoes get the skin of their soles thickened into a regular human leather, almost half an inch thick, and as tough as rawhide. A somewhat similar condition develops in the palms of the hands of those who work hard with spades, axes, or other tools.

Any good process carried to excess becomes bad, and this is true of this power of callus formation in the skin; for parts of it which are under constant pressure, like the surface of the toes inside the shoe, and particularly of the outside toes, the little and the big toe, develop under that pressure patches of thickened, horny skin, which we call corns. These patches start to grow into cone-shaped projections or buttons; but being prevented from growing outward by the pressure of the shoe, they turn upon themselves and burrow into the skin itself, and we get the well-known ingrowing corn.

If there is anything in the human body which we ought to be thoroughly ashamed of, it is corns; for they are caused by our own vanity, and nothing else, in cramping our feet into shoes one or two sizes too small for them. There are a number of things that can be done to relieve the discomfort of the corn, but the only sure way is to remove its cause, namely, the tight shoe.

Under other kinds of irritation, the skin has the power of growing curious little button-like buds, or projections, which we call warts. These are commonest in childhood, and generally disappear at about twelve or fifteen years of age, when we no longer delight in dirt, and glory in mud pies.