THE EESi:^ OF FICUS EUBIOINOSA. 
47 
could be prociu'ed in this way. The compound with potash, when heated on the 
platinum-foil, melts, takes tire, putFs up, and burns with the vivacity of other nitro- 
compounds. 
Action of Heat on Sycoretin. 
^Vhen heated in a retort, sycoretin melts below 100° C. (212° Fahr.), and, at a tem- 
perature a few degrees higher, froths considerably, ghlng otf water which retains the 
pecuhar odour perceptible on heating the original resin. On raising the temperature 
much higher it becomes quiet, and begins to decompose, giving off at first a mobile 
liquid, and towards the end a dark yellow tar-like substance, leaving only a small quan- 
tity of charcoal behind. The distillate so obtained has a disagreeable smell, somewhat 
like burnt india-rubber ; acetic acid being also present in considerable quantity. 
Treated with a solution of carbonate of sodium the acetic acid is removed, a dark 
brown oily liquid remaining, which possesses now a less disagreeable odour. This oily 
liquid, submitted to a new distillation, gives at first a very fluid liquid, possessing in 
every respect the properties of caoutchin, and then a thick oily liquid, which soon 
becomes dark bromi when exposed to the air. 
Acetate of Sycoceryl. 
W e assign this name, for reasons hereafter to be mentioned, to the crystallizable sub- 
stance, which, as ah’eady mentioned, is obtained when the residue, left after the treat- 
ment of the original resin with cold alcohol, is dissolved in boiling alcohol, and the 
solution allowed to cool. 
For the preparation of this substance the original resin is coarsely powdered and 
extracted with cold alcohol, in order to remove, as far as possible, the sycoretin. The 
undissolved residue is then exhausted with boiling alcohol. The several solutions thus 
obtained are filtered and allowed to cool, when a white deposit is formed, which gene- 
rally shows but little indication of crystallization. This white deposit is again dissolved 
in a large quantity of boiling alcohol, and left in a quiet place to cool slowly, Avhen a 
more perfect crystallization is obtained. 
Towards the latter period of the ciystallization a substance is deposited of different 
appearance, being of a more fiocculent nature, and altogether different from the crystals 
first deposited. This substance is present only in a very small quantity, and its separa- 
tion from the other crystallizable constituents of the resin is attended with great diffi- 
culties. In order to effect this separation, the alcoholic solution is allowed to cool to 
about 40° C. (104° Faiir.), and then the crystals which may have formed are separated by 
straining off the liquor as c[uickly as possible through a piece of gauze. The mother- 
liquor, on further cooling, will now deposit the fiocculent substance, contaminated how- 
ever with the first substance. By repeating this operation a perfect separation of this 
second substance may be effected. 
The crystalline substance (acetate of sycoceryl), by repeated solution in and recrystal- 
lization from hot alcohol, was obtained perfectly v/hite and transparent and apparently 
pui’e. An examination with the microscope, however, proved that another foreign 
H 2 
