POTASSIUM. 33 



judiciously combined with iron. As an alkaliniser of the 

 plasma, although exceedingly transitory in its action, being 

 very rapidly excreted, potash is a valuable remedy in gout, where 

 it combines with the excess of uric acid in the blood and facili- 

 tates its excretion. The carbonates, citrates, and tartrates of 

 potash in various forms, and the waters of such spas as Baden- 

 Baden, Wiesbaden, Vichy, Carlsbad, and Aix-la-Chapelle, which 

 contain definite though small quantities of potassium salts, are 

 extensively used for the treatment of acute and chronic gout. 

 The salts of the vegetable acids, or the effervescing carbonates, 

 are the best preparations for prolonged use. In acute rheu- 

 matism the bicarbonate, citrate, tartrate, and acetate are suc- 

 cessfully employed to increase the alkalinity of the blood. For 

 restoration of the red corpuscles in anaemia by the increase of 

 their potash element, the carbonate is the best haematinic, 

 either as contained in the Mistura Ferri Composita, or given asi 

 a pill with sulphate of iron (Blaud's Pill). 



An indirect action of potash on the blood must here be 

 carefully noted. We shall see hereafter that citric, tartaric, 

 and acetic acids, given internally, are partially oxydised in 

 the blood. The completeness of the combustion, and of the 

 important influences which the change exerts on the blood and 

 kidneys, depends upon the combination of the vegetable acid 

 with an alkali. Citric acid, e.g., is excreted mostly unchanged 

 in the urine, but citrate of potash is entirely, or almost entirely, 

 thrown out as the carbonate. 



3. SPECIFIC ACTION AND L'SES. 



Potash depresses the muscular, nervous, and cardiac 

 tissues ; and the point of interest in this connection is, that 

 when given for other purposes it must be used with caution. 

 The danger of " potash poisoning " is, however, exaggerated, 

 for the drug passes so quickly through the system, that it 

 cannot well produce a deleterious effect on the tissues, unless 

 given for a very long time, or in disease of the excreting 

 organs, especially the kidneys. Excessive single doses are 

 generally rejected at once by vomiting. 



4. REMOTE LOCAL ACTION AND USES. 



Potash is excreted almost entirely by the kidneys ; to a 

 much less extent by the skin, respiratory passages, stomach, 

 liver, biliary passages, and bowels. Inoth.rwunls.it passes 

 out in the fluids of all the secretory surfaces, and in doing so 

 it stimulates the cells to increased activity. 



The diuretic effect of several potash salts, referable to thoir 

 influence upon the renal epithelium, is the most important of 

 D 8 



