and Observations on Lac. 
197 
solution to evaporation or distillation, or by previously pouring 
it into water with which a small quantity of muriatic or acetic 
acid has been mixed; for thus, when the whole is heated, a 
curdy precipitate of resin is formed, and may be separated by a 
filter, after which, the liquor may be evaporated, in order to 
obtain any resin, or other substance, which may remain in solu- 
tion after the first operation. 
The solution formed by digesting stick lac in alcohol, without 
heat, is of a dark brownish-red colour, and the insoluble part 
subsides, in the state of a dark coloured magma ; this retains 
the greater part of the colouring matter, which, as I have al- 
ready observed, is most easily soluble in water. 
The proportion of resin thus dissolved, when stick lac is 
treated with alcohol, has, in my experiments, amounted to 67 
or 68 per cent, but this must depend on the quality of the 
samples. 
The seed lac which I examined was very pure, and yielded 
to alcohol about 88 per cent, of resin : it contained but little of 
the colouring matter; and the other substances subsided, and 
formed a cloud at the bottom of the glass vessel. 
Shell lac in small fragments, by simple digestion with alcohol, 
afforded in the first instance nearly 81 per cent. Part of the resin, 
however, still remained mixed with the residuum, and could not 
be separated but by subsequent operations : this part amounted to 
about 10; so that the total quantity of resin, in the shell lac 
which I employed, may be estimated at 91 per cent. 
When the shell lac was only reduced into small fragments, 
these (after the separation of the first portion of resin) re- 
tained their figure, but were become more bulky, very elastic, 
