| yield a larger proportion of salts, than most kinds 
and among these Mrmiwood is said to produce the largest 
__ This kind of salt never pre-exists.in the vegetable, but is alw 
_ Rerated during the burning. These salts are acrid and caustic. 
| Potassa is of extensive use in medicine, and particularly serviceable _ 
in complaints of the stomach and intestines, produced by acids. The — 
medicinal virtues of this‘salt are to attenuate the juices, resolve ob- 
structions, and promote the natural secretions. A diluted solution of - 
‘it, drank warm in bed, generally excites sweat ; if that evacuation is not 
favored, its sensible operation is by urine. When acidities abound _ 
m the first passages, this salt absorbs the acid, and unites with it into” 
a mild, aperient, neutral salt. As one of its principal effects is to _ 
render the animal fluids more thin, it is obvious that where they are _ 
already colliquated as in scurvies, and in all putrid disorders in ge- 
__ neral this medicine is improper. + : 
The common dose of this salt is from two or three grains to a scru= 
_ ple, or even toadrachm. Its acrimony must, however, be sheathed 
with some mucilage, or largely diluted with some watery liquors. 
But pearl ash is more frequently employed in a neutralized state — 
with vegetable acids. It is of late employed in calculous complaints, 
but its continued use seldom fails to injure the cons ss "ee 
Intestinal canal. - SS, 20 aa 
~ It is applied externally in solution asa lotion to a 
_ the skin when constricted in a parching hot fever ; it is also used as 
 astimulant fo the inactive state of the vessels, in certain foul ulcers. 
+ Carbonate of potash, acetite of potash, sulphate of potash, and 
other preparations from this base, generally possessmuch the same 
amas of Tartar.—Super tartrite of potash—is a concrete sa- 
line matter, which separates from wines after they have undergone 
complete fermentation ; it adheres to the top and sides of the cask, 
in red, or whitish grey crystals, according to the color of the liquor. 
‘In this state it is called crude tartar, and when purified, crystals, or 
cream of tartar. % oe 
» This salt is a mild, cooling, aperient and laxative medicine, if 
half or a whole ounce of it be taken in substance, with treacle or — 
any other vehicle, it proves an effectual purgative. Further, when 
dissolved in water, it affords, with the addition of sugar, an agreea- 
ble acidulated drink, which is of great service in ardent fevers ; and 
likewise forms a pleasant beverage during the summer. It is also to 
be regarded as a valuable diuretic, and one which is efficacious in the 
treatment of drepsy. It is given under two modes of exhibition in 
which its effects are somewhat different. When given dissolved in a 
large quantity of water, tothe extent of four or six drachms a day, 
itacts simply as a diuretic ; when given'to the same extent, gradually 
increased, in the form of an electuary, without the free use of dilu- 
ents, along with a more or less diuretic effect, it acts as a hydragogae 
athartic. The latter is the more usual, and perhaps, the more suc- 
mode of exhibition. : : oa 
