APOC YNACEA, 3889 
communicates gradually to the palate a slightly bitter but not 
disagreeable taste. 
Microscopic structure.—The cortical tissue is covered with a 
thin suberous coat, the middle layer of the bark is built up of a 
thin-walled parenchyme, through which enormous, hard, thick-. 
walled cells are scattered in great numbers, and are visible to 
the naked eye, as they form large irregular groups of a bright 
yellow colour. ‘Towards the inner part these stone-cells dis- 
appear, the tissue being traversed by undulated medullary rays, 
loaded with very small starch grains; many of the other 
parenchymatous cells of the liber contain crystals of calcium 
oxalate. The longitudinal section of the liber exhibits large 
but not very numerous laticiferous vessels, as elongated simple 
cells with perforated tranverse walls (sieve-cells) containing 
a brownish mass, the concrete milk-juice with which all parts 
of the tree abound. 
Chemical composition.—In 1875, Jobst and Hesse exhausted 
the powdered bark with petroleum ether, and then extracted, 
by boiling alcohol, the salt of an alkaloid, which they called 
Ditamine. After the evaporation of the alcohol, it is preci- 
pitated by carbonate of sodium and dissolved by ether, from 
which it is removed by shaking it with acetic acid. Ditamine 
as again isolated from the acetate forms an amorphous and 
somewhat crystalline, bitterish powder of decidedly alkaline 
character ; the bark yields about 0°92 per cent. 
From the substances extracted by means of petroleum, 
ether, as above stated, Jobst and Hesse further isolated (1) 
Echicaontchin, C?5H*°O2, an amorphous yellow mass; (2) 
Echicerin, C*°H*8O?%, forming acicular crystals, melting at 
157° C.;{3) Echitin, C5°H*?0%, crystallized scales, melting 
_ at 170°; (4) Echitein, C#*H7°O*, which forms rhombic prisms, 
melting at 195°; (5) Echiretin, C5°H°°O*, an amorphous 
substance, melting at 62° C. 
Echicaontchin may be written thus: (C5H®) 502, echicerin 
(CH®)02, echiretin (C°H®)’O* ; these formule at once ep 
cate how nearly the three substances are | io 
