Comparative Analysis of the Gum Resins. 357 
gum gave nearly the same results with frankincense : 7. e. a 
great quantity of mucous acid, oxalic acid, and very little 
malic acid. 
D. The alcoholic solution A when inspissated to dryness 
furnished 17-5 grammes of a resin, which exhibited the 
following characters: 
1. It is of a reddish-yellow, transparent, and brittle like 
wax at a cold temperature, having an tindulating and glossy 
fracture, slightly receiving the impression of the nail, and 
easily becoming soft in the mouth or “between the fingers. 
It has no remarkable taste. | Tt smells like gum ammonia. 
It does not become idio+electrical. wore 
2. Like wax, this resin welts at a temperature of 43° of 
the thermometer. “At a higher temperature it swells con- 
siderably, gives out a particular'smell, and leaves.a spongy 
light charcoal occupying’ a/eood dealof room. 
3. This resi udites easily avith the alkalisy even when 
cold, and soapy solutions of considerable: bittertiéss are pro- 
duced #j1it .o3istoqevs modw & rostuloe 2uooups 31 
4, The sulphuric acid dissolves with fadility the resin of 
gum ammonia, particularly ata gentle heat. Water de- 
composes this soliition:’ if! we Heat it'more, there results a 
hydrogenated charcoal; ‘which after having been washed was 
dissolved in the nitric acid, and furnished’ by evaporation 
an astringent substante Which precipitates glue in brown. 
5. The nitric acid when heated on the resin of gum am- 
monia, at first only gave some white vapours; but suddenly 
these nitric vapours appeared with great’ vehemence, and 
there was produced'a yellow resiniform substatice, which 
was dissolved during the operation. cOn inSpissating the 
liquor I obtained.a résinous-bitter substance of! a very pure 
yellow, fusible at a gentle heat, uniting with’ the alkalis, so- 
luble in alcoho! and in boiling water, and depositing’ a little 
therefrom upon cooling ; partly'soluble also in a great quan- 
tity of cold water, and commanicating to its solutions a 
very beautiful yellow, which athheres very strongly to the 
fingers, and may be fixed with’ gteat. facility to silk and 
woollen, giving them a superb ‘Justre, unalterable by the 
oxygenated muriatic acid, and even by the weak alkalis: 
in solidity therefore it seems to he far superior to any dye- 
stuff we are acquainted with. 1 miay even add, that so far 
#3 economy is concerned, this fine colour seems to merit 4 
* The soap of pitch-resin is also very bitter to the taste ; which seems to 
- bespeak very energetic properties as existing in these resins, which ought 
therefore to fix the attention of medical practitioners. 
“G3 pre- 
