Chemistry. — Iv 
15. Pyromucic Acid.—This acid was obtained by M. Houton 
Labillardiere by distilling saclactic or mucic acid. The matter 
that comes over is to be mixed with four times its weight of 
water, and then evaporated to the requisite degree; the new 
acid is deposited in crystals, and new crystals may be obtained 
by concentrating the mother-liquor still further. When put into 
a retort, and heated to the temperature of 266°, they melt, and 
sublime in the form of yellow crystals, which, on being redissolved 
in water and crystallized, become perfectly white and pure. 
Pyromucic acid is white, has an acid taste, but is destitute of 
smell. When heated to 266°, it melts, and sublimes, and con- 
denses into a liquid which becomes solid on cooling. It does 
not deliquesce. It reddens vegetable blues ; is more soluble in 
hot than cold water; it is more soluble in alcohol than water ; it 
neutralizes the salifiable bases, and forms salts, most of which 
crystallize. Pyromucate of barytes is composed of 
eo Na oe pee nat Ot A ais Mins eat 13-331 
LoL eile eS iS Bo ea an se Sha 9-750 
99-9: 
When analyzed, by means of peroxide of copper, its consti- 
tuents were found to be: 
Cason itis Oat bie no ydan Te 5-118 
Peper nen cana ns fete r ese Cars sae 45°806 
SOOO RS Oe roca th tas See a cc ne es, carey 
100-035 
The number of atoms coming nearest to these proportions, and 
to the weight of the equivalent number for the acid, as indicated 
by the composition of pyromucate of barytes, is as follows : 
9 atoms carbon. .... Se PEF dee 50°94 
6 atoms oxygen .... = 6°00 ...... 45°28 
4 atoms hydrogen... = 0°50 ...... 3°78 
13°25 100-00 
(See Ann. de Chim. et de Phys. ix, 365.)— 
16. Rheumic and Zumic Acids—The existence of these two 
acids as peculiar bodies has been destroyed. M. Lassaigne has 
shown that the acid in the juice of the rheum ponticum is nothing 
else than oxalic acid.—(Annals of Philosophy, xiii, 71.) 
Vogel has shown that the zumic acid possesses the characters 
of the lactic acid? If this statement he correct, the lactic acid 
is a product of the vegetable kingdom, or at least formed 
by the fermentation of vegetable bodies (Ibid. xii. 391). 
It is curious that this acid, to which Braconnot had given the 
"name of nanceic acid, was called zwmic acid both in this country 
