RESIN OF JALAP. 
35 
cohol evaporates, the resin is precipitated under the form of 
a thick and colorless turpentine. The supernatant water is 
separated, the resin is spread out on the sides of the capsule', 
and the heat is continued until it is perfectly dry, when it is 
so friable that it may easily be reduced to a fine powder. 
This powder is as white as starch ; every kilogramme of 
jalap, of good quality, gives a hundred grammes of pure 
resin ; a result which agrees very well with the quantitative 
analysis. This resin has been tried ; it is as active as that 
obtained by the other processes, by which it is not produced 
in the white state. Three decigrammes, suspended in half 
a glassful of milk of almonds, acted as a powerful purgative, 
in the dose of even two decigrammes, its action was almost 
as energetic. Reduced to powder, and put in contact with 
cold water, it presents the peculiar characteristic of forming 
a semi-fluid, transparant mass, as if it had been melted ; it 
has the same appearance as resin which has just been pre- 
cipitated by water from its alcoholic solution. Under this 
form, it would seem to re-constitute a hydrate, by again 
taking up the water which it had lost by desiccation ; how- 
ever, this character may be used to a certain point for dis- 
tinguishing the resin of jalap from other resins, which re- 
main pulverulent during their contact with water. If a 
certain quantity of colophane be mixed with resin of jalap 
in powder, and treated by water, the whole mass combines, 
but with an opaque appearance, occasioned by the colophane, 
which, as it cannot be incoporated with water, remains in- 
terposed in the middle of the mass. However, this charac- 
ter would not be sufficiently accurate for determining a small 
quantity of foreign resin put in for the sake of sophisticat- 
ing the pure resin. By an analogous means, the other re- 
sins, which, like that of jalap, are entirely insoluble in 
water, might be extracted. 
Ibid, from Journ. de Pharm, et de Chim. 
