234 M. B. WELCH. 
it is bound to “‘sweat’’ eventually. The presence of an oleo- 
resin in the timber is, of course, well known, and references. 
are often met with as to its unsuitability for instrument or 
clock cases, on account of articles placed in them becoming 
sticky. Inthe present inquiry small boxes were made, and 
metal articles placed in them soon acquired the character- 
istic odour of the timber, indicating that the oil is decidedly 
volatile at ordinary temperatures. . 
A microscopical examination of a specimen of the reddish 
coloured heart-wood of the timber, which was felled in 1891 
was made, but it was at first found difficult to prove the 
actual presence of an oleo-resin. No trace of resin passages. 
was found, such as occur for example in many coniferous. 
woods, and in the Dipterocarpeze. In many of the vessels. 
a dark brown deposit was found, but since this proved 
insoluble in the various solvents tried, it was hardly pos- 
sible that it could cause the exudation. Sections treated 
with a dilute caustic potash solution, however, at once 
showed small round globules in certain of the cells, which, 
with a solution of alkannin in 50% alcohol gave the charac- 
teristic red colouration of resinous or oily bodies. A section 
was boiled in N. caustic potash for several minutes without. 
affecting the contents of the vessels appreciably, but 
numerous rounded globules appeared in the cells of the 
xylem parenchyma (para- and metatracheal in this case) and 
also in the cells of the medullary rays. These globules. 
were quite soluble in 100% alcohol. Sections boiled in 
water and then treated with alkannin also showed small 
globules, particularly in the elongated parenchymatous. | 
tissue. From the rapid rounding up of the oily contents 
of the cells into globules, when treated with caustic potash, 
even in the cold, it is probable that the oil is present in 
very minute droplets surrounding the walls of the cells. 
Caustic potash also has the effect of liberating a pinkish 
