Synonyms. — Silica. Silicea Tera. Silex. Decarbonized white pebble. Acidium Silicicum. The proper name is Silicic Oxide. Common Names. — Pure Flint or Quartz. Silicious Earth> Chemical Properties. — Formula, Si02. Prepared by fusing silica and carbonate of sodium ; dissolving residue filtered and precipitated by hydrochloric acid. It is a white powder, hav- ing neither taste nor smell. Preparation. — Pure Silicea is triturated according to Class VII, American Homoeopathic Pharmacopoeia. Dr. P. Wilde uses preferably the silicate of soda known as " liquid glass," which is freely soluble in water. (See "Administration.") Physiologico-chemical Data. — Although this inorganic salt is found very abundantly throughout the vegetable kingdom, especially in grasses, grain, palms, etc., it is found compara- tively little in the animal kingdom, notably so in the higher orders, the vertebrae. Traces of Silicea, however, are found in the ashes of blood, bile or urine, and larger quantities (7 per cent.) in the white of egg, and even more in the ashes of the epidermis, hair and nails. It is also found in the connec- tive tissue, and hence its action on the spinal cord, brain and nerves must be referred to the investing membrane, the con- nective tissue, of the nerve-fibres. Disturbance of the func- tion of the Silicea molecules causes a turgescence of the cells of the connective tissues involved. This swelling may re- main stationary for a time, then disappear or occasion sup- puration. General Action. — Silicea acts more upon the organic sub- stances of the body, involving prominently bones, joints, glands, skin and mucous surfaces, producing malnutrition 130 THE TWELVE TISSUE REMEDIES. and corresponding to the scrofulous diathesis. Its action is deep and long-lasting. It is especially suited to imperfectly nourished constitutions, owing to deficient assimilation. It is the remedy for ailments attended with pus-formation, and is closely related to all fistulous burrowings. Wherever pus is formed in an inflamed part of connective tissue or skin, Silicea may be used. Deeply-seated scrofulous cachexia and some forms of septic infections (vaccine) find in it a valuable general remedy. Like Calc. sulph., Silicea corresponds to the process of suppuration, with the following distinguishing fea- tures : Silicea ripens abscess, since it promotes suppuration. Calc. sulph., by restraining: the suppurative process, heals sup- purating wounds. As long as infiltration, which can only dis- appear by suppuration, lasts, Silicea is the remedy, and should be continued until all the infiltrated parts have disappeared. If then the wound fails to heal, give Calc. stdph. Ailments affecting the periosteum. Deep-seated suppurations, pus thick and yellow ; also in certain reflex affections connected with the nerves. After suppuration has ceased to be active, but the process lingers and the pus forms chronic depots, small or large, fistulous or otherwise ; also, where the general organism is both irritable and weak, and the nervous system is easily aroused to exhausting agitation (as Dunham says, it is contra- indicated by general nerve torpor), this is a specific remedy. In localized exhaustion, when the symptoms resemble paraly- sis— e. £-., rectal distention, dilated and irritable heart, great general debility, as after lying-in — it should always be thought of. In general hypersesthesia and exaggerated reflexes. Silicea has also the power to reabsorb a bloody or sero- albuminous exudate, existing within the tissues by means of the lymphatics. Here it often follows Calc. phos. Silicea cures chronic gouty rheumatic affections by means of its stimulating effects of the involved connective tissue cells, compelling these to throw off the accumulated urates through the lymphatics. Silicea can restore suppressed foot-sweats, and in this way be an indirect remedy for diseases resulting from suppression SIUCEA. 131 of foot-sweat, for instance : Amblyopia, cataract, paralyses, etc. If the cells of any part of the connective tissue show a lack of Silicea molecules, they atrophy in consequence. Guiding Symptoms and Characteristic Indications. Mental Symptoms — Thought difficult, attention difficult to fix, can be aroused but tires easily, stronger mentally than physi- cally ; he has grit. Desponding, peevish, disgust of life. Oversensitive to noise, etc., and with anxiety. Great irrita- bility. A peculiar mental abstraction, marked by a propensity to toy by the hour with pins and needles. Brain-fag, school girls become confused during recitations because they cannot concentrate their thoughts ; want to think but are unable to do so. Head and Scalp. — Vertigo, patient inclines to fall forward or to the left. Labyrinthine vertigo. Headaches with vertigo, with small nodules on scalp, from hunger, from abdominal ir- ritation, from overstudy, from nervous exhaustion. Headache is throbbing, beating, pressing asunder and coldness of head, with constant need for wrapping it up. Headache from nape to vertex, more on right side, aggravated by noise, exertion, light, study, and relieved by warmth. Pressive headache from above downward, with intermittent itching of vulva. Cerebral apo- plexy, preceded by deep-seated stitches in the right parietal region and dull, heavy, crampy pain in arms. Scalp very sen- sitive and sore ; itching. Painful pustules. Suppurating wounds. Sweat on head of children, like to keep the head wrapped up warm ; large, open fontanelles. Offensive erup- tion on occiput. Hair falls out. Cephalaematoma. Nodules on scalp.