POSTZYGAPOPHYSIAL 



1169 



POTASSIUM 



Postzygapophysial ( post-zi-gap-off-iz'-e-al) [post, be- 

 hind ve; axoowjtc, apophysis]. Pertaining 

 to the postzygapophysis. 



Postzygapophysis (post-zi-gap-off'-is-is) [post, be- 

 hind; -', "• yoke; a-6ovoic, apophysis]. An ar- 

 ticular process proceeding from the posterior face 

 of the neural arch of a vertebra. 



Pot [ME., pot, a pot]. A urinal. P. -bellied, having 

 a prominent belly. P.-belly, a protuberant belly. 

 P. -gutted, pot-bellied. 



Potable (po'-ta-bl) [potare, to drink]. Fit or whole- 

 le to drink — applied to waters for drinking in dis- 

 :ion to those for medicinal use. 



Potain's Solution. A solution for diluting the blood in 

 counting the red corpuscles. It consists of three 

 solutions — one of gum arabic, one of sodium sul- 

 phate, and one of sodium chlorid, each of a specific 

 gravity of 1020. These liquids are mixed in equal 

 proportions. 



Potamopyra ( pot-am-ot/ -ir-ah ) [-oraftoc , river ; Tip, 

 heat, lire]. Malarial fever. 



Potash (pot'-ash) [potassa, potash]. I. Potassium 

 carbonate prepared by boiling wood-ashes with water 

 and evaporating the solution. It is also obtained 

 from potassium chlorid and potassium sulphate found 

 in the Stassfurt salt-beds. The residue left behind in 

 the manufacture of beet-root sugar also yields potash . 

 Finally, from the wash-water of sheep's wool, con- 

 siderable quantities of potash are obtained. 2. 

 Caustic potash, potassium hydroxid. 



Potassa | po-tas'-ah) [L.]. I. See Potash. 2. Potas- 

 sium hydroxid. P. cum calce, Vienna paste, made 

 by rubbing together equal parts of caustic potash and 

 quick-lime. It is used as a caustic. Potassae, Liquor, 

 " solution of potassa,'' consists of hydrate 56, distilled 

 water 944 parts; combined with bitter tonics it is 

 useful in atonic dyspepsia. Locally, it is used as a 

 wash in scaly skin-diseases. Dose n^v-^ss, diluted. 



Potassamid {po - las' - am- id) [potassa, potassium; 

 amid~\, NH.,K. A substitution-compound of ammo- 

 nia; a yellowish-brown, inflammable substance, pro- 

 duced by heating metallic potassium in ammoniacal 

 gas. 



Potassic [po-tas'-ik) [potassa, potash]. Containing 

 Potassium. 



Potassiferous {po-tasif'-er-us) [potassa, potash ; ferre, 

 to bear]. Containing or yielding potassic salts. 



Potassinum \po-tas'-in-um). Synonym of Potassium. 



Potassio-ferric {po-tas' -e-o-fer' -ik) [potassa, potas- 

 sium ; fa-rum, iron]. Combined with iron and potas- 

 sium. 



Potassio-mercuric (po-tas'-e-o-mer-ku'-rik) [potassa, 

 potassium ; Mercury, a Grecian god]. Combined with 

 potassium and mercury. 



Potassium {po-tas' '-e-um) [potassa, potash]. K = 

 39; quantivalence I ; sp. gr. 0.865. A metallic ele- 

 ment, of silvery luster, and characterized by intense 

 affinity for oxygen. See Elements, Table of. Its pecu- 

 liar reactions are : its precipitation when converted 

 into the acid tartrate ; its precipitation by platinum 

 perchlorid ; the violet color it imparts to the flame. 

 Physiologically, salts of potassium are protoplasmic 

 poisons when applied locally in sufficient concentra- 

 tion. They dialyze more readily than sodium salts. 

 In the body they occur especially in the solid struc- 

 tures, while sodium salts predominate in the fluids. 

 In large doses, by the mouth, potassium salts act as 

 irritants to the gastrointestinal tract. The circulation 

 is generally depressed by potassium salts — after small 

 Kes the primary depression of the pulse-rate and 

 xterial pressure is followed by. a rise of both ; large 

 doses cause a rapid fall of pressure and pulse-rate. 

 74 





Injected into a vein, salts of potassium cause paralysis 

 of the heart. Potassium salts are obtained from the 

 ash of plants, from saltpeter, from the potassium 

 bitartrate deposited from urine in the process of fer- 

 mentation, and from the washings of sheeps' wool. 

 The action of the various salts is given under their 

 proper heading. P. acetas, KC.,H 3 (J 2 , an easily solu- 

 ble salt having marked diuretic properties. Dose 

 gr. v— gj. Purgative doses jij-iv. P. Amalgam, 

 a mixture, in various proportions, of potassium and 

 mercury. The compound may be a liquid, or an 

 amorphous or crystalline solid. P. arsenitis, Liquor, 

 Fowler's solution. See under Arsenic. P. bicar- 

 bonas, KHCO s , a salt with properties like the carbon- 

 ate, to which it is preferable. Dose gr. v-xxx. Liq. 

 potas. efferves. (B. P.) Dose jv-x. P. bichro- 

 mas, K 2 Cr 2 7 , a substance occurring in large, irregu- 

 lar, yellow crystals. It is used in the preparation of 

 hardening fluids, and has been applied externally in 

 syphilis. P. bitartras, KHC 4 H 4 2 . See P. tartras. 

 Dose gr. xx- ^ ss. Pulvis effervescens comp. , com- 

 pound effervescing powder, " Seidlitz powder," con- 

 tains 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 result- 

 ing when potassium cyanid and a ferric salt are mixed. 

 It is used in dyeing. P. bromas, KBr, a colorless, 

 crystalline, bitter salt, readily soluble in water. It is 

 extensively employed as a sedative in nervous excite- 

 ment, and is one of the best drugs in epilepsy. Its 

 prolonged use causes the condition known as Bromism, 

 q. v. P. carbonas, (K,C0 3 )j.3rL,0, useful locally 

 in acne and acute eczema, internally in rheumatism, 

 in the uric-acid diathesis, and in jaundice. Dose gr. 

 ij-xx. P., Caustic, potassium hydroxid, q. v. P. 

 chloras, KC10 3 , a crystalline compound, with a saline, 

 cooling taste. It is soluble in 15 or 16 parts of 

 cold, and readily soluble in boiling water. It is used 

 as a gargle in diseases of the mouth and throat, in 

 mercurial stomatitis, etc. Dose gr. v-xx. In toxic 

 doses it causes disorganization of the blood (convert- 

 ing the hemoglobin into methemoglobin) and intense 

 irritation of the kidneys, with hematuria and blood- 

 casts. Sir James Y. Simpson recommended it in 

 doses of 20 grains thrice daily, in threatened abortion 

 from fatty degeneration of the placenta. P. chloratis, 

 Troch., each containing gr. v. of the salt. Dose j-iij. 

 P. chlorid., KC1, a colorless, crystalline substance, 

 of bitter taste. P. citras, K 3 C 6 H 5 0-.H..O, is used 

 in solution as a febrifuge, a diuretic, and to alkalin- 

 ize the urine. Dose gr. x-xxx. P. citratis, Liq., 

 citric acid 6, potas. bicarb. 8 ; filter and add dis- 

 tilled water ad 50 parts. Dose ^ss-j. P. citratis, 

 Mist., "neutral mixture" — lemon-juice 100, potas. 

 bicarb, q. s. ad saturationem. Dose Jss-j. P. 

 cobalto-nitrite, unof. , has been used successfully 

 in angina pectoris and asthma. Dose gr. ss-j. P. 

 cyanid., KCX, made from potassium ferrocyanid 

 by the action of heat, sometimes with (also without) 

 the addition of potassium carbonate and charcoal. It 

 is very soluble in water, has active reducing powers, 

 and is very poisonous. It has the sedative and anti- 

 spasmodic action of hydrocyanic acid, and, like it, 

 is used in gastric irritability and cough. Dose ^ 

 grain. P. dichromas. Synonym of P. bichromas. 

 P. ethylas, C 2 H 5 OK, a crystalline substance, de- 

 composing in the presence of organic matter into 

 metallic potassium and ethyl alcohol. The potassium 

 abstracts oxygen from the tissues, and thus is caustic ; 

 the ethyl alcohol is antiseptic. P. et sodii tartras, 

 KXaC 4 H 4 6 .4H 2 0, " Rochelle salt," laxative. Dose 

 ^ ss-j. P. ferricyanid, K 3 FeC 6 X 6 , red prussiate 



