Silicon

Silicon (Silicium), chem. symbol Si, atomic number 14; metalloid of the carbon group, atomic weight 28.06. Obtained in crystalline form in the form of black needles with melting point 1,451°, as well as in an amorphous (more active) state; dissolves in hot alkalis and in a mixture of hydrofluoric and nitric acids. In free state is not found in nature; in the form of various compounds it is one of the main components of the earth's crust (natural silicates-minerals). Silica SiO₂ (silicon anhydride, silicon dioxide) is very widespread, entering into the composition of many rocks (quartz, tridymite, cristobalite, amorphous silica). In small amounts silica is widely distributed in animal tissues and fluids, in epithelial formations, glands, connective tissues, muscles, blood, milk, urine (more in herbivores' urine), urinary stones, etc. The shells of some lower animals (bacilli, infusoria) consist of silica. Silica forms the skeleton of sponges, the shells of diatoms (which make up diatomaceous earth), is contained in the hard parts of straw, in some species of horsetails, bamboo. Silica is a white powder, soluble only in hydrofluoric acid. By fusing silica with salts of Na and potassium, sodium and potassium silicate are obtained. Solutions of these salts are called water glass. In technology water glass is used in putty for metal objects as an adhesive for joining glass and stone, for impregnating fabrics, making them fire-resistant, in soap-making-as a filler for soap. The use of silicic acid H₂SiO₃ and its salts has also become widespread in therapy. Silicates-glass and clay-are of great importance. Observations (Kunkel u. Kail) established a dependence between the function of the pancreas and silicon metabolism; tubercular and cancerous patients excrete less silicic acid with urine than healthy ones. The silica content in the pancreas is decreased in acute tuberculosis, while in cases of cured tuberculosis it is increased. The introduction of silicon compounds into the body causes leukocytosis, accelerates scar formation, improves subjective symptoms: appetite, well-being, lowers temperature (in tuberculosis), reduces itching (pruritus senilis), has a beneficial effect on angina pectoris attacks. These results of the action of silicon compounds served as the reason for the use of silicon in tuberculosis of the lungs, arteriosclerosis, skin diseases, etc. Other authors deny both the specific action of silicon and the favorable results of its use, or consider it as a means of causing irritation of the protoplasm (Reiztherapie). Preparations of silica: 1. Amorphous silicic acid--Acidum silicicum amorphum; dose 0.06 twice a day in tablets, preferably with calcium phosphate, in delayed ossification of cartilage. 2. Liquid sodium glass-Liquor natrii silicici-natrium silicicum liquidum-is used for rigid surgical dressings made of cardboard, gauze, etc. 3. Natrium silicicum purissimum siccum - internally: in pills for uric acid diathesis, dose-0.1-0.25 per day. For tuberculosis, arteriosclerosis, disfiguring arthritis-0.05 three times a day. For pemphigus-0.1-up to 10 times a day. Intravenously: 0.01 in a 1% solution-once a week for tuberculosis, arteriosclerosis, bronchial asthma. 4. Silicol - Silicol - silicic, metaphosphoric casein-preparation, containing 0.1 g of colloidal silica per tablet, 2-3 times a day for tuberculosis and skin diseases. 5. Silistren-tetraglycolic ester of orthosilicic acid with 18% SiO₂; syrupy, hygroscopic liquid. Used for pulmonary tuberculosis and for treating non-healing wounds; adults-25-30 drops 3 times a day after meals, children-10-15 drops 2 times a day. 6. Siliquid-colloidal preparation of silica, not containing protein as a protective colloid, contains 0.3% SiO₂. Causes leukocytosis and is used intravenously in 0.5-1.0 cm³ doses for infectious diseases (typhoid fever), septicemia, etc. Side effects when using silica preparations: intensification of the process in the lungs in deeply cavitated cases, local tissue irritation when subcutaneous and intramuscular administration of colloidal silica preparations, when intravenous administration-sometimes chills. To reduce the alkalinity of the solution of Natr. silicici purissimi sicci when administered intravenously, minimal amounts of iodine are added. Contraindications to the use of silicon preparations are kidney diseases.