AKD PHARMACOrCEIA. 527 



broken in pieces, and boiled in water, so as to make a strono- 

 decoction. This decoction proves very serviceable in irritability 

 of the bladder, if used as a glyster, the bowels having been pre- 

 viously emptied : for this purpose the decoction should be made 

 stronger, by boiling it for some time. Although the capsules of 

 the red poppy contain opium, yet it is in such small quantity, 

 that they are rarely, if ever, used as an anodyne. 



It seems very probable that the good eifect of this decoction 

 depends in a great measure upon the opium which is extracted 

 from the poppy heads : it may be better, therefore, to dissolve in 

 gruel a proper dose of opium, when an anodyne glyster is re- 

 quired, as we cannot be accurate in respect to quantity when 

 the decoction of poppies is employed. It has been ascertained 

 that the anodyne or narcotic qualities of opium are diminished 

 by long boiling, and that the extract of poppies, however care- 

 fully prepared, is very inferior in every respect to opium. No 

 hesitation, therefore, should be felt in preferring opium to the 

 extract or decoction of wdiite poppy heads, whether it be wanted 

 for a clyster, a drench, or a fomentation. 



POTASH. — Potassa. (New name. Protoxide of Potas- 

 sium.) There is a great variety of preparations of potassa used 

 in medicine, as the liquor potassce, or solution of potassa, which 

 is diuretic and antacid ; the poiasscB fusa, or fused potassa, a 

 caustic deliquescent salt ; the potassa cum calce, or potassa with 

 lime, a milder caustic ; the potassce hitartras, or bitartrate of 

 potassa. With sulphuric acid it forms vitriolated tartar, or sal 

 polychrest (Sulphate of Potash); with nitrous acid, that very 

 useful medicine termed nitre (Nitrate of Potash), which, contrary 

 to what we have just observed, is a diuretic in a moderate dose 

 (see Nitre); and with vinegar, or acetous acid, it makes so- 

 luble tartar ( Tartarised Potash), The pearlash of commerce is 

 the carbonate of potash, and is in a very impui-e state, and not 

 applicable to chemical or medical purposes. When sufficiently 

 purified, it is joined with diuretics, purgatives, and tonics, with 

 advantage. In those cases which require the use of tonics there 

 is sometimes an acidity in the stomach, which potash corrects; 

 and it renders purgative medicines more easy of solution. 

 Given alone it acts as a diuretic. When neutralised with acids 

 it has a laxative property, but requires to be given in large 

 doses. The purified potash is named in the shops Sub-carbonate 

 of Potash ; formerly called Salt of Tartar, or Prepared Kali, or 

 Salt of Wormwood. When potash is deprived of the carbonic 

 acid with which it is naturally combined, it becomes a strong 

 caustic ; and when diluted is sometimes employed as a wash for 

 the mange. In this state it is termed Pure Potash, or Kali, and 

 is seldom used internally. (See Alkalies.) With carbonic 

 acid it is named Carbonate of Potash. 



u. 



