194, RUBIACEZ), 
found to be most valuable. In 1870, Broughton examined the 
fresh bark of one of the Hymenodictyons, and found that the 
bark when dry was almost tasteless owing to the transforma- 
tion of that substance into esculetin, the decomposition having — 
been induced by contact with decaying organic matter. 
H. obovatum, the dry bark of the former tree being extremely 
bitter. . ogee 
Description,—The bark of H. excelsum is very bitter, 
and may be distinguished from that of H. obovatum by its red 
colour and bitterness. The minute structure resembles that of 
the Cinchonas, but the bundles of stone cells are larger, 
spiral and laticiferous vessels also are more numerous, the latt 
from branches about one inch in diameter, . 
Chemical composition.—From an examination of the b 
made by W. A. H. Naylor in 1883, it appears that the - bitt 
principle is not the glucoside eesculin, or its decompositi 
product, zsculetin, but an alkaloidal substance allied to qui- 
noidine, berberine and paricine. From quinoidine it differs 
being optically inactive, and from its double compound ¢ 
taining relatively less platinum. From berberine it differs i 
that it contains a higher percentage of carbon » while its donb 
compound also yields a relatively larger amount of platinun 
From paricine it differs only in the percentage of hydrogen 
gives. Mr. Naylor considers it to be a new alkaloid having | 
composition corresponding to the empirical formula C24H*°N 
and therefore an addition to the small class of bases devoi 
oxygen. Besides Hymenodictyonine, which is the name 
to the new alkaloid, Mr. Naylor has separated a bit 
neutral principle, represented by the formula C27H** 
