MR. JOHNSTON ON THE CONSTITUTION OF THE RESINS. 
365 
These are equivalent to 
A. 
B. 
C.10 H3I Og 
Carbon 
75*12 
75*21 
75*59 
Hydrogen 
9*79 
9*87 
9*56 
Oxygen 
1509 
14*92 
14*85 
100 100 100 
2. The same portion of crude euphorbium being treated with a second quantity of 
cold alcohol, gave a solution from which the resin was obtained as above described, 
washed with water and dried at 212 ° Fahr. When burned in the air it left 1 per 
cent, of ash. 
A. 771 grs. (7*61 grs. pure resin) gave C = 21*0, and H = 7'03 grs. 
B. 8*19 grs. (8*075 grs. pure resin) gave C — 22*28, and H = 7'38grs.; or per cent., 
A. 
B. 
Carbon 76*29 
76*30 
40 
atoms. 
Hydrogen 10*26 
10*15 
32*6 
atoms. 
Oxygen 13*45 
13*55 
5*43 atoms. 
100 100 
The difference between the results obtained from this and from the former portion, 
may be ascribed either to a difference in the mode of heating the two portions, the 
latter after drying at 212 ° Fahr. having been further fused at a slightly elevated tem- 
perature, when bubbles of volatile matter began to show themselves ; or to an ad- 
mixture of the less soluble resin (B.) contained in the euphorbium of commerce, 
which according to the analysis of Rose, contains more hydrogen and less oxygen 
than are present in the more soluble resin (A.). At all events the fractional atom of 
oxygen exhibited by the results of these second analyses, shows that the portion ana- 
lysed is not to be considered as a pure resin. 
3. To determine this point the crude resin was treated with a third portion of cold 
alcohol, and the solution, which was much paler in colour and less concentrated than 
either of the former, was submitted to evaporation. As the alcohol was drawn off, 
the solution became milky, and gradually deposited a portion of a white powder, 
which was the second resin of euphorbium. This resin, therefore, is soluble to some 
extent in cold alcohol, and is consequently capable of being taken up along with the 
more soluble resin, and in greater quantity, of course, by the second than by the first 
portion of alcohol with which the tears may be treated. 
The remainder of the second portion which had been analysed, when treated with 
a small quantity of alcohol, readily dissolved, with the exception of a slight residue, 
which resembled the powder of the second resin. It is not unlikely, therefore, that 
even the resin employed in the first series of analyses might contain a little of resin 
B, by which the carbon and hydrogen would be slightly increased. The form ula 
c 40 H 31 0 6 deduced from them, though agreeing very closely with the experimental 
