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.