206 RUBIACEZ. 
Microscopie structure.—The greyish pulp surrounding the 
seeds is composed of large oval cells containing a little gra- 
nular matter. The pulp of the pericarp is remarkable for 
numerous large reddish-brown stony cells. The epidermis i 
formed of tessalated cells of irregular size and shape. The 
albumen of the seeds is horny and translucent. 
Chemical composition.—The active principle of the fruits is 
saponin, which forms a large proportion of the pulp surrounding 
the seeds. The fresh pulp was mixed with water and the juice 
expressed ; the filtered liquor had the following properties :—Ié 
was acid in reaction and very frothy, it gave opaque white 
precipitates with diluted mineral acids, a greenish colour and 
transparent jelly with ferric chloride, a yellow colour with caustic 
soda, noreaction with iodine, and ipitate with two vi 
of rectified spirit. Acetate of lead caused sucha thick mixture 
as to allow. the vessel to be inverted without the contents flow- 
ing out. A measured quantity of the solution, represent 
a weighed quantity of the dried pulp, was boiled for one hour 
with dilute HCl, after which the insoluble sapogenin was 
filtrate. Calculations from these results showed that the pul 
contained about one-third its weight of saponin, and that on 
an average about four grains of this principle existed in each 
fenthsy <5; : ee. 
An extract was also obtained by exhausting the pulp wit 
hot spirit and evaporating tke united liquors to dryness. This” 
extract was soluble in water, except a little waxy matter, and 
the solution was acid and frothy. It gave a green coloration 
with ferric chloride, turning red with ammonia, yellow pre- 
cipitates with barium hydrate and the acetates of lead, a red 
colour with caustic soda, and negative reactions with gelatine 
and iodine solutions and alkaloidal tests, This solution gave 
a precipitate when boiled with dilute acid, and showed an 
increase in glucose corresponding with that obtained in # 
decomposition of saponin, Evaporated. portions of the 
tion eae a purple colour in contact with strong sulp 
ric acid, : Pt Se es 
wt 
