August 26, 1871.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
1G3 
per cent, of nitrogen; tlie difference in nitrogen, 
namely 2T4 per cent, is, according to Teligot, part 
of caseine, and corresponds to 13‘7 per cent, of 
caseine, a quantity sufficiently large to play an im¬ 
portant part in tlie process of nutrition. 
Lithle Citras. —Citric acid neutralized by the 
addition of carbonate of litliia and the resulting salt 
dried. A white deliquescent salt, blackening when 
heated, and when calcined with free exposure to air 
leaving a white residue of carbonate. 20 grains thus 
incinerated leave 10 - 57 grains. 
for Sfuknts. 
CHEMICAL NOTES TO THE PHARMACOPOEIA. 
BY WILLIAM A. TILDEN, D.SC. LOND. 
DEMONSTRATOR OF PRACTICAL CHEMISTRY TO THE 
PHARMACEUTICAL SOCIETY. 
Liquor Sodas Chlorat.e. 
A solution of chloride, hypochlorite, and bicarbo¬ 
nate of sodium, obtained by passing clilorine gas into 
a cold solution of carbonate of soda. 
Na 2 C0 3 + Cl 2 + H 2 0 + Na 2 C0 3 
= NaCl + NaCIO + 2 (NaHCO,). 
Properties and reactions similar to those of calx 
clilorata. 
Liquor Zixci Chloridi. —Granulated zinc is dis¬ 
solved in hydrochloric acid, and the iron and lead, 
which are usually present, removed by addition of 
clilorine water, and digestion of the solution upon 
excess of carbonate of zinc. The foreign metals are 
in this way thrown out of solution as hydrated 
oxides:— 
2 (Fe C1 2 ).C1 2 + 3 Zn O. C 0 2 + aH 2 0 
— Fe 2 0 3 a;H 2 0 -j- 3ZnCL -|- 3C0 2 , 
and 
PbCl 2 .Cl 2 + 2Zn0C0 2 
= Pb0 2 + 2ZnCl 2 + 2 C O,. 
After filtration the liquid is evaporated to the 
proper bulk. 
The solution contains 175 grains of zinc, or 3G6 
grains of chloride of zinc, in a fluid ounce. 
Lithle Carboxas. — The minerals from which 
lithium is obtained, are silicates of aluminium and 
one or several of the alkali metals, part of the 
sodium or potassium being replaced by a chemically 
equivalent quantity of lithium. One of the best 
methods of treating these minerals consists in heat¬ 
ing the finely powdered material with quicklime and 
a little chloride of calcium. The alkali is thus 
rendered soluble in the form of chloride, and can 
easily be converted into any compound that may be 
required. 
[§ In white powder or in minute crystalline 
grains, alkaline in reaction, soluble in 100 parts of 
cold water, insoluble in alcohol. It dissolves with 
effervescence in hydrochloric acid; and the solution 
evaporated to dryness leaves a residue of chloride of 
lithium, wliich communicates a red colour to the 
flame of a spirit-lamp, and, redissolved in water, 
yields a precipitate with phosphate of soda.] * Car¬ 
bonate of litliia thus differs from the potassium or 
sodium carbonate in being but slightly soluble in 
water ; it is also partially decomposed by long igni¬ 
tion, becoming converted into oxide. 
Lithium salts are also distinguished from those of 
potassium and sodium by the sparing solubility of 
the phosphate and by the easy solubility of the pla- 
tino-cliloride. 
Magnesia. —Carbonate of magnesia is heated to 
redness, till a portion taken from the middle of the 
crucible and allowed to cool, no longer effervesces 
with a dilute acid :— 
(MgC0 3 \Mg(H0) 2 4H 2 0 = 382, leaves 
4MgO = 160. 
4 ounces, therefore, leave PG7 or nearly If 
ounces. 
[§ Dissolved in nitric acid and neutralized with a 
mixture of ammonia and chloride of ammonium, it 
does not give any precipitate with oxalate of am¬ 
monia or chloride of barium.] 
The absence of lime and sulphate of magnesium or 
sodium is thus indicated. 
Magnesia Levis. — [§ A bulky white powder, 
differing from the preceding preparation only in its 
greater levity, the volumes corresponding to the 
same weight being to each other in the ratio of 
three and a half to one.] 
Magnesle Carbonas. —Boiling solutions of sul¬ 
phate of magnesia and carbonate of soda are mixed 
and evaporated to dryness. The residue, after 
thorough washing with boiling water to remove sul¬ 
phate and excess of carbonate of sodium, is the salt 
required:— 
3 Mg S 0 4 + 3Na,C0 3 1 
MgS0 4 + Na 2 C0 3 + 5H 2 0| 
3 Mg C 0 3 3 Na 2 S0 4 
Mg O . 5 H 2 0 Na 2 S0 4 -f CO,. 
The official carbonate is, therefore, not a simple 
carbonate, but a hydrate carbonate. A similar con¬ 
stitution belongs to all the precipitated carbonates, 
except those of barium, strontium and calcium. 
A normal carbonate containing 3 mols. of water 
of crystallization, MgC0 3 .3H,0 is deposited in 
crystals by exposure of liq. mag. carb. to the air. 
The only probable impurities are calcic carbonate 
and sulphate of sodium or basic magnesium sulphate. 
These are easily detected by dissolving in hydro¬ 
chloric acid and then adding excess of ammonia and 
some oxalate for the first, or chloride of barium for 
the second. 
Magnesle Carbonas Levis. —Both this and the 
heavy carbonate possess the same composition and 
are partly crystalline. 
THE ETYMOLOGY OF THE WORD OPODELDOC. 
BY J. BORLAND. 
A short time ago, as I was perusing some of the older 
volumes of the Pharmaceutical Journal, my attention 
was arrested by a reply which appears in notices to cor¬ 
respondents, Yol. VII. page 248, 1865. 
The editor who then was there states, “We arc unable 
to give the derivation of the term Opodeldoc.” 
Now, although I have read the Journal for many 
years, and always with that amount of careful attention 
which it merits, as the representative organ of pharma¬ 
ceutical learning in all its phases, I had not previously 
observed this remark ; and when I read it I felt a little 
