66 
DE. STENHOUSE ON LAEIXINIC ACID. 
it is decomposed by carbonic acid. It contained a considerable quantity of potash ; but 
I have not been able to obtain it of a constant composition. 
A solution of laiixinic acid gives no precipitate, either with lime-water or with 
saccharate of lime. The behaviour of larixinic acid with baryta is extremely singular 
and characteristic. When a solution of caustic baryta is added to a concentrated 
aqueous solution of larixinic acid, the latter being in excess, a bulky, semitransparent, 
gelatinous precipitate immediately falls, and if the solutions are concentrated fills the 
whole vessel. This precipitate, which considerably resembles hydrated alumina, is but 
slightly soluble in cold water; but it dissolves very readily in boiling water, from 
which it is again deposited on the cooling of the liquid. This baryta compound is 
readily decomposed by carbonic acid. When thrown on a filter and washed, the air 
beuig carefully excluded, it was dried in vacuo over sulphuric acid, and was then found 
to contain, as the mean of two experiments, 34’ 92 per cent, of baryta. 
A solution of larixinic acid yields no precipitate with either basic or neutral acetate 
of lead, neither is it precipitated by nitrate or ammonio-nitrate of silver ; but when its 
solution m the latter salt is boiled, the silver is reduced in a pulverulent state, Larixinic 
acid forms no precipitate -svith perchloride of platinum, even on the application of heat. 
It does not contam any nitrogen. It does not reduce oxide of copper when tried by 
Tkommee’s test. It dissolves in concentrated sulphuric acid, but no conjugate combina- 
tion is produced, as was ascertained by neutralizing with carbonate of baryta, larixinic 
acid bemg obtained nnchanged. When larixinic acid is boiled with a mixture of 
hych’ochloric acid and chlorate of potassa, it is decomposed, but without the formation 
of chloranile. When it is boiled with a solution of hypochlorite of lime, no coloration 
is produced. It is readily attacked by nitric acid, especially when assisted by heat ; 
nitrous fumes are given off, and oxalic acid is the only fixed product. It is also readily 
attacked by bromine, especially when assisted by heat. Abundant vapours of hydro- 
bromic acid are given off, the larixinic acid being entirely destroyed and converted into 
an unciystallizable resin. The salts of copper produce an emerald-green colour in solu- 
tions of larixinic acid, but no precipitate. Chloride of manganese produces neither 
coloration nor precipitation. Protosulphate of iron strikes a brownish-red colour with 
solutions of larixinic acid, which acquire a brighter red colour on standing, resem- 
bling meconate of iron, Perchloride and persulphate of iron produce a beautiful 
pm-ple dahlia-colour, which is very persistent, and stands dilution well. Its reactions 
with salts of hon are very characteristic of larixinic acid, which forms an excellent 
reagent for the detection of salts of iron, even in very minute quantity. In this way 
the presence of hon, in tolerably pure sulphate of copper, can readily be detected by the 
purple coloration produced. Larixinic acid does not affect neutral protonitrate of mer- 
cury in the cold ; and on the application of heat no mercury is reduced. 
Larixinic acid appears to be peculiar to the larch tree ; at least I have not been able 
to find a trace of it in the bark of the spruce fir [Abies excelsa), or in that of the Scotch 
fir [Pinus sylvestris). Larixinic acid evidently belongs to that small group of substances 
