Chemical Properties. — Formula, Mg HP04, 7H20. It is made by mixing phosphate of soda with sulphate of magnesia. The crystals resulting are six-sided, needle-like. They have a cooling, sweetish taste. They are sparingly soluble in water ; 322 parts dissolving one part after standing a long time. Boil- ing decomposes it. It exists in the grains of cereals, and can be detected in considerable quantity in beer. Preparation. — The salt is triturated according to Class VII, American Homoeopathic Pharmacopoeia. Physiologico-chemical Data. — It is an earthy constituent of muscle, nerves, bone, brain, teeth and blood corpuscles. A disturbance of its molecular motion causes cramps, pains and paralysis. Schiissler says that the action of Magnes. phos. is the reverse of that of iron. By functional disturbance of the molecules of the latter the muscular fibres relax ; through the functional disturbances of the magnesium molecules they con- tract ; hence it is the remedy for cramps, convulsions and other nervous phenomena. General Action. — Diseases having their seat in the nerve- fibre cells or in the terminal bulbs of the nerves, in the muscles or in the muscular tissue itself, are cured by this remedy. Pains which are darting, spasmodic in character, boring, lightning-like, accompanied by a constrictive feeling. They MAGNESIA PHOSPHORICA. 93 are often changing in locality, and are relieved by warmth and pressure. It is purely antispasmodic, and hence is curative in cramps, spasms of the glottis, tetanus, epilepsy, spasmodic retention of the urine, paralysis agitans, etc. It is best adapted to lean, thin, emaciated persons of a highly nervous organiza- tion, and prefers light complexion and the right side of the body. Cold in general favors its action exceedingly, whereas heat and pressure interfere with it. Hence the patient is relieved by these. Attacks are often attended with great prostration and sometimes with profuse sweat. The Magnes. phos. patient is languid, tired, exhausted, unable to sit up, whether he is suffering from acute or chronic affections. Guiding Symptoms and General Characteristics. Mental Symptoms. — Illusions of the senses, forgetful, dulness and inability to think clearly, indisposition to mental effort. Sobbing with lamenting. Laments all the time about the pain, with hiccoughing. Talking to herself constantly or sitting still in moody silence. Carries things from place to place. Head and Scalp. — Brain troubles of children, with uncon- sciousness and convulsive symptoms. Headache, pains shoot- ing, darting, stabbing, shifting, intermittent, spasmodic, par- oxysmal and neuralgic, always relieved by the application of warmth. Nervous headaches with sparks before the eyes. Very acute pains in the head, more in young and strong per- sons, constant while attending school or after mental labor, or from any injurious stimulus. Pain on top and back of head extending down the spine, most severe between the shoulders. Headache from occiput, spreading over whole head with nausea and chilliness. Scalp feels rough ; much dandruff ; pustules.