LACTUCA VIROSA AND SATIVA. 35 
removed some carbonate of lime ; on filtration and evaporation 
an acid crystalline salt of ammonia was obtained, which was 
procured in very white masses by frequent recrystallization 
with addition of caustic ammonia. 
The salt was dissolved in water, again precipitated with 
basic acetate of lead, the precipitate collected, edulcorated and 
decomposed with sulphuretted hydrogen, upon which the clear 
acid was evaporated to a certain degree, and then exposed to 
the heat of summer. In the course of 14 days numerous 
crystals had formed, which in 14 days more, during which 
time the solution had evaporated down to about half, increased 
considerably in quantity and size, and after careful collection 
and washing with a little cold water appeared as prismatic tri- 
lateral columns with obtuse terminations ; those, on the con- 
trary, which were applied to the side of the basin resembled 
butterflies' wings ; the latter crystals, dissolved in spirit and 
crystallized, then dissolved in water and recrystallized, formed 
colorless, regular, prismatic, tabular crystals. 
The residuous acid liquid was mixed with water and with 
sulphuret of barium, and finally saturated with some carbonate 
of barytes, the soluble salt of barytes carefully decomposed 
with dilute sulphuric acid, and the acid obtained evaporated. 
It could not be obtained in a crystalline state, but when dried 
for several weeks at a moderate heat formed a white efflores- 
cent salt. This dried acid, heated in a glass tube, was de- 
composed with effervescence and evolution of irritating acid 
vapors, which were partly deposited on the cold sides of the 
tube in the form of a sublimate (maleic acid) and the residue 
consisted of a white acid crust (fumaric acid.) It was conse- 
quently malic acid. For further confirmation the acid was 
dissolved in water, and chloride of potassium added to the so- 
lution, and to another sample, lime-water; both, however, 
without producing any change. A solution of acetate of lead 
immediately formed a caseous precipitate, which melted like 
a resin in boiling water. 
The precipitate obtained by saturating with sulphuret of 
