GRUENBERG AND Gres: NOTES ON ‘BASTARD’ LOGWOOD 375 
freshly prepared solution of the commercial “ extract of logwood,”’ 
and a solution four weeks old that had faded to’a straw-yellow. 
The chemical alterations. undergone by the aqueous solution 
of the commercial extract are accompanied by such a decided 
change in color and in chemical properties that from a com- 
parative study of such extracts we expected to learn something 
definite regarding the actual differences between the pigments in 
the heart-wood of “red’’ logwood and in that of the bastard 
variety. We were unable, however, to do so. 
Experiments were started to determine, if possible, the relations 
of light and of air to the discoloration of solutions of logwood 
extracts. In a few weeks all the preparations had been attacked 
by growths of Penicillium, Rhizopus and other fungi. After 
filtration the solutions showed no appreciable differences in shade 
or color. But on diluting these filtered solutions with two parts 
of water and eventually with eight parts, differences were readily 
observed. 
The solutions which had been in the light showed no change 
in color, whereas those kept in the dark had become distinctly 
yellow. The extracts to which the air had free access manifested 
the greatest changes. 
SOLID MATTER IN LOGWOOD EXTRACTS. — We desired to ascer- 
tain, in comparative determinations, the quantities of solid matter 
in aqueous extracts of the various logwoods under investigation. 
The absolute amount of solid substance in 100 c.c. of the extract 
was always small —less than 0.02 gram. In the drying process 
slight decomposition seemed to result and perfectly constant 
weights could be obtained only after a long time. Although the 
absolute changes in weight were only very small, the proportion- 
ate variations in quantities so slight were quite large. For these 
reasons no comparative observations were attempted in this con- 
nection. The use of very large volumes of extract, to reduce the 
comparative effects of the variations referred to, was impracticable. 
The general question of the physiology or chemistry of pig- 
ment-formation in the heart-wood was not approached at all, nor 
were the histological characters of the varieties compared. 
There can be no doubt that “bastard” logwood is, as Prof. 
Earle also concludes (see page 368) a distinct variety or subspecies 
