60 ON THE CONSTITUENTS OF LACTUCARIUM. 
exhausted with water, and the insokible residue- treated 
several times with hot alcohol of 0.833. On the slow eva- 
poration of the latter, a somewhat yellowish lactucerine 
was obtained, which was purified by washing with water, 
re-soUuion in alcohol and crystallization. The quantity of 
lactucerine amounted to 53.5 per cent. 
Lactucerine forms snow-white aggregated granules, and 
dissolves in strong hot alcohol, from which it again sepa- 
rates on cooling ; the alcoholic solution faintly reddens litmus 
paper. It dissolves readily in ether, but not in water, when 
pure. When warmed in a platinum dish, it becomes tena- 
cious and transparent, like turpentine ; when heated more 
strongly, it melts completely to a clear yellow oil, gives off 
white vapours possessing an agreeable odour, and is vola- 
tilized v/ith the exception of a slight residue of a perfectly 
combustible cinder. Heated in a closed glass tube in a bath 
of chloride of zinc, it still continues pulverulent at 131° F., 
becomes decomposed at 158°, and disengages aromatic acid 
vapours at 200°. At 212° it experiences scarcely any loss; 
at 298° it becomes tenacious and like turpentine, without 
melting; at 320° it forms a thick liquid; between 356° and 
374° it becomes thinner, and loses 2.110 percent. The 
residue, again dissolved in spirit, separates, but still of a 
yellow colour. Melted at 374° in hydrogen gas, it gives 
off aromatic vapours, and loses 4.04 per cent, in weight. 
Submitted to destructive distillation, it melts, becomes yel- 
low, and gives off white vapours, which condense to a 
colourless liquid; subsequently a yellow oily liquid distils 
over, and lastly a dark oil; the residue consists of a thin 
coating of a shining black coal. The gases which escaped 
produced no turbidness in lime-water, nor could they be 
set light to. The distillate consisted of a colourless aqueous 
acid layer and a heavier yellowish-brown oil. The odour 
was pungent, acid and aromatic. The acid aqueous liquid 
