Potassium

(po-tas' '-e-um). K 39; quantivalence I; sp. gr. 0.865. A metallic element, of silvery luster, and characterized by intense affinity for oxygen. See Elements, Table of. Its peculiar reactions are: its precipitation when converted into the acid tartrate; its precipitation by platinum per chlorid; the violet color it imparts to the flame. Physiologically, salts of pota ium are protoplasmic poisons when applied locally in sufficient concentration. They dialyze more readily than sodium salts. In the body they occur especially in the solid structures, while sodium salts predominate in the fluids. In large doses, by the mouth, pota ium salts act as irritants to the gastrointestinal tract. The circulation is generally depre ed by pota ium salts after small Kes the primary depre ion of the pulse-rate and xterial pre ure is followed by. a rise of both; large doses cause a rapid fall of pre ure and pulse-rate. Injected into a vein, salts of pota ium cause paralysis of the heart. Pota ium salts are obtained from the ash of plants, from saltpeter, from the pota ium bitartrate deposited from urine in the proce of fer from various the washings of sheeps' The action mentation, of and the salts is given under wool. their proper heading. P. acetas, an easily soluble salt having marked diuretic properties. Dose gr. v— gj. Purgative doses jij-iv. P. Amalgam, a mixture, in various proportions, of pota ium and mercury. The compound may be a liquid, or an amorphous or crystalline solid. P. arsenitis, Liquor, Fowler's solution. See under Arsenic. P. bicarb on as, KHCOs, a salt with properties like the carbonate, to which it is preferable. Dose gr. Liq. pot as. efferves. (B. P.) Dose jv-x. P. bichromas, a substance occurring in large, irregular, yellow crystals. It is used in the preparation of hardening fluids, and has been applied externally in syphilis. P. bitartras, See P. tartras. Dose gr. xx . Pulvis effervescens comp., compound effervescing powder, " Seidlitz powder," contains of the preceding gr. 120, mixed with sodium bicarb, gr. 40, in the blue paper; and tartaric acid gr. 35 in the white paper. P.-blue, the blue color resulting when pota ium cyanid and a ferric salt are mixed. It is used in dyeing. P. bromas, KBr, a colorle , crystalline, bitter salt, readily soluble in water. It is extensively employed as a sedative in nervous excitement, and is one of the best drugs in epilepsy.