Hay Fever.--A most effective preventive and cure for this is the inhaling through the nostrils the vapour of strong acetic acid. The acid may be on a sponge enclosed in a smelling bottle, and its vapour may be freely inhaled. Sponge all over each night with hot acid and water. The head also may be wet with pretty strong acid, and tied up so as to keep in the vapour. Do not, however, use a waterproof covering. Headache.--There is a vast variety of ailments associated with what is called headache. In itself, it is just more or less _pain_ in the head. When there is such pain, it means that some of the nerves in the head are in a wrong state, probably in nearly all cases a state of more or less _pressure_. This pressure hinders the free flow of vital action along the nerve, and this hindrance we feel as pain. To remove the pressure is, then, to relieve the pain. Pressure from overwork often causes headache on week-days, which goes off on Sabbath. The _rest_ here removes the pressure, and so the pain. The pressure results from a failure of energy in some part of the head, slight swelling then taking place. To increase the energy is to effect a cure. This may be done by first, at bedtime, soaping the back with warm water and SOAP (_see_). Then dry, and rub firmly yet gently with hot olive oil, until the whole back glows with warmth. This may take perhaps fifteen minutes. Then give three minutes of warm water pouring over the back. Dry again, and oil with hot oil, and put the patient to bed. Avoid much tea. Avoid altogether tobacco and alcoholic liquors, which of themselves will often cause the trouble. This treatment applies to all that numerous class of headaches which arise from overwork and fag. A cure may often be had by its means, without taking a holiday. But where this can be done, it is well to take it. The headache, however, may be caused indirectly by the failure of some of the organs to do their duty, when other methods must be adopted. The use of tobacco so injuriously affects the whole system that headache often results, and refuses to be cured unless the tobacco be given up. It is hard to do this, but the difficulty must be faced. Cold, damp feet are a common cause of headaches. Let these be well bathed (_see_ Bathing Feet) for some days, even twice or three times a day, and many kinds of headaches will be cured. Constipation, or sluggish action of the bowels, frequently causes headache. The cure is obvious (_see_ Constipation). Imperfect action of the kidneys also causes it. In such a case apply a large, warm bran poultice (_see_) across the back behind the kidneys. Oil the skin before and after poulticing. Do this once a day at bedtime for a week, if necessary, but not longer than a week at a time. Take half a teacupful of water before each meal. Use freely the lemon drink described in Drinks, Refreshing.