Olim, Tartarum Solubile. E. TARTRAS KALI. D.
_Kali Tartarizatum._ P.L. 1787.
_Tartarum Solubile_. P.L. 1745.
QUALITIES. _Form_; this salt, although ordered to be crystallized, is
generally kept in its granular form. _Taste_, bitter and cool. CHEMICAL
COMPOSITION. It consists of one proportional of acid, and one
proportional of base. SOLUBILITY. When in its crystalline form it is
soluble in its own weight of water, but in its ordinary granular form, 4
parts are required for its solution; hence, compared with the insoluble
super-tartrate, it has justly acquired the name of _soluble_ tartar;
when long kept in solution, its acid is decomposed, and its alkali
remains in a state of a _sub-carbonate_. It is also readily soluble in
alcohol. INCOMPATIBLE SUBSTANCES. _Magnesia_, _baryta_, and _lime_;
_acetate_ and _sub-acetate of lead_, and _nitrate of silver_ decompose
it. All acids, even the _carbonic_,[616] and _acidulous salts_,
_tamarinds_, and other _sub-acid vegetables_, by neutralizing a
proportion of the base, convert it into the state of super-tartrate;
this fact offers another illustration of the chemical law of affinity,
explained under the head of _sulphate of potass_. The practitioner
should bear this in his recollection, for I have frequently seen a dose
of _soluble tartar_ directed in the acidulated _infusion of roses_; the
result was of course very different from that which the author of the
prescription intended to produce. MED. USES. It is a mild and efficient
purgative, and forms a very valuable adjunct to resinous purgatives or
to senna, the griping properties of which it corrects by accelerating
their operation. _Form. 70._ DOSE, ʒj to ℥j, in solution.