POTASSIUM SULPHATE 181 



(Christison). It appears to act much in the same manner 

 as sulphuretted hydrogen, decomposing the haemoglobin of 

 the blood, and causing nervous and muscular paralysis. 



MEDICINAL USES. It has been used in chronic cough, 

 rheumatism, and skin diseases, in doses of 3*- *o 3ii]-> f r 

 horses and cattle, and grs. ij. to grs. x. for dogs. Once a 

 panacea for all kinds of poisoning, it is now used only in 

 poisoning by lead, which it converts into a black, insoluble, 

 and almost inert sulphide. 



POTASSIUM SULPHATE. Potassii Sulphas. Sulphate of 



Potash. K 2 S0 4 . 

 POTASSIUM BISULPHATE. Bisulphate of Potash. KHS0 4 . 



Potassium sulphate is got from certain salt mines, and 

 from the mineral kainite, which is a double sulphate of 

 potassium and magnesium. It occurs in transparent, colour- 

 less, rhombic prisms, which have a sharp, saline, bitter taste, 

 are hard and difficult to powder, and dissolve in ten parts of 

 cold water, and in four parts of boiling water. 



The bisulphate is the residue in the preparation of nitric 

 acid from nitre and sulphuric acid. It is colourless, crystal- 

 line, and soluble, with an acid taste, and an acid reaction. 

 It is distinguished from the neutral sulphate by its small 

 flat prisms, its greater fusibility and solubility in water, its 

 acid taste and reaction, and its decomposing carbonates with 

 effervescence a property which has led to its being occa- 

 sionally substituted for tartaric acid in making effervescent 

 powders. 



ACTIONS AND USES. They are cathartic, cholagogue, and 

 diuretic. As cathartics they cause both hydragogue and 

 peristaltic actions, while as diuretics they are less certain 

 than the nitrate or acetate. On account of its hardness and 

 inaptness to absorb moisture, potassium sulphate is used 

 for facilitating trituration of such tough vegetable substances 

 as opium, ipecacuanha, and jalap. 



POTASSIUM IODIDE. Potassii lodidum KI. (See Iodine 

 and Iodides.) 



POTASSIUM BROMIDE. Potassii Bromidum. KBr. (See 

 Bromine and Bromides.) 



