34 
ItESIN OF JALAP. 
The liquors of these decoctions are rejected as useless ; 
hut they might he used for preparing an aqueous extract of 
jalap. 
After these three treatments, the water runs out quite co- 
lorless, and there remains only pure resin fixed in t"he ligne- 
ous matter. It is then heated by alcohol ; for that purpose, 
the exhausted roots, as they come out of the press, are 
placed in the sand-hath of. an alembic ; a sufficient quantity 
of alcohol at G5° C. is then added. Alcohol at S5° C. which 
was first directed, has the inconvenience of hardening the 
roots by removing the small quantity of water which they 
retain, and consequently impedes the solution of the resin 
fixed in the interior of the ligneous slices. The sand-bath 
is then covered with its head ; it is boiled for ten minutes ; 
and when the whole is nearly cold, it is pressed in the same 
manner as directed for the aqueous decoctions. Two simi- 
lar treatments are also. made, after which the roots are en- 
tirely exhausted. All the alcoholic decoctions are then 
mixed ; the liquor which results has a very slight amber 
tint, which soon disappears on a small quantity of finely di- 
vided animal charcoal being stirred with it ; it is filtered, 
and then distilled in the sand-bath until nothing passes over. 
The resin remains fluid at the bottom of the sand-bath, un- 
der the water and alcohol: it requires only to be dried; if, 
instead of operating in a tin sand-bath, an untinned copper 
one be used, the resin has a blackish appearance, owing to 
an insoluble matter mechanically contained in it. This 
matter, which appears to be a combination of the resin with 
the copper of the sand-bath, exists only in very small quan- 
tity ; however, small as that quantity is, it is necessary to 
remove it for the resin to appear white ; and as it is only 
interposed, it is sufficient, to separate it from the mass, to 
dissolve the resin in twice or three times its bulk of alcohol 
of 65° C, to add a very small quantity of animal charcoal 
and to filter. The alcohol passes off quite colorless; it is 
evaporated in a capsule placed on boiling water; as the al- 
