322
ELEMENTS OF MATEKIA MEDICA.
(
Composition. —Some difference of opinion exists as to the atomic iconstitution of this salt, as is obvious from the following table:—
Brande and Phillips.
Eq. Eq.Wt. PerCt.
Soda. 1.... 32.... 18*2
Graham and Turner.
F.q.
Eq.Wt.
PerCent.
2 ..
.... 62-6...
... 17*20
. 1 ..
.... 71-4...
.... 19*94
.25..
....225-0...
.... 62-84
Berzelims.
(E'tperimient.)
-177*67
_20-33
.612-00
Crystallized Phosphate Soda 1_176.... 100*0
1.359*0. 99*98
100-00
According to Mr. Graham, one of the twenty-five equivalents of'waterperforms the function of a base to the acid.
Physiological Effects. —In doses of an ounce, or an ounce and ahalf, it acts as a mild antiphlogistic purgative, like sulphate of soda. Insmall and continued doses it has been used with the view of altering thecomposition of the blood, and of promoting the deposit of phosphate oflime in the bones.
Uses. —As a purgative it is employed in the diseases of children anddelicate persons, in preference to other saline substances, on accountof its slight taste and mild action on the stomach. It is well adapted forfebrile and inflammatory disorders.
It is one of the substances which have been employed in cholera, torestore to the blood its deficient saline matters (I)r. O’Shauglmessy, Meporton the Chemical Pathology of the Malignant Cholera, p. 54). On account,of the phosphoric acid which it contains it has been supposed to be iparticularly applicable in those diseases in which there is a deficiency ofphosphate of lime in the bones. It has also been administered indiabetes. j
Administration. —As a purgative it is given in doses of from six to jtwelve drachms. It is best taken in broth or soup. As an alterative the]dose is one or two scruples three or four times a day.
So'dee Car'bonas. — Car'donate of So'da.
History. —This salt, as well as the sesquicarbonate of soda, was pro-bably known to the ancients under the term of virpov, or nitrum (videPotassce Nitras, p. 292; also Soda Sesquicarbonas). The salt-alkali, or>;sagimen vitri of Geber ( Invent. of Verity, ch. iv., and Search of Perfec-tion, ch. iii.) was a carbonate of soda: the word sagimen is a corruption;of the Hindee term sajjiloon, (Dr. Royle, Essay on Hindoo Medicine,\p. 41). In modem times this salt has had various appellations, such as;mild mineral or fossil alkali, aerated mineral alkali, subcarbonate of soda,and natrum carbonicum.
Natural History.— It is found in crystals, or in the form of an efflo-rescent powder, in several parts of the world. According to Klaproth (quoted by Dr. Thomson, in his Outlines of Mineralogy, vol . i. p. 96),.jit occurs at Debrezin, in Hungary , and Montenuovo, near Naples.Beudant (quoted by Necker in his Regne Mineral, t . 2 rac . p.667) lias;analyzed three native carbonates of soda: one from Lac Blanc, in Hun 'gary; a second from Egypt; and a third from Vesuvius . Carbonate soda ]is a constituent of some mineral waters, which are, in consequence, itermed alkaline, or, when they also contain a large excess of carbonic jacid, acidulo-alkaline (see p. 148). i
Preparation. —It may be procured from barilla, from kelp, or from jsulphate of soda. j