622 PROFESSOR BAYLEY BALFOUR ON THE 
different sexes. But all the forms assumed by the tree—and it does vary much 
both with habitat and with age—are referable, we consider, to the one species. 
The young plant has always much longer and broader leaves than the older 
plants, and in these latter the inflorescences are shorter and more compact. 
In unsheltered localities, too, as might be expected, the tree is frequently of a 
more dwarfed size than when well protected. 
The resin exudes naturally through cracks and rents in the stem, and these 
are increased in size by the collector. The amount of resin produced varies 
with their situation. The mode of collection is very simple. Holding below 
the seat of exudation a small piece of goatskin abont a foot square, the gatherer 
chips with a knife the resin from the stem, and catches it on the skin. The 
time for collecting is immediately after the rains, and there are therefore two 
gatherings in the year, and the resin is exported immediately after collecting 
to Makullah, the Persian Gulf, and elsewhere, the Sultan taking tithe of all 
export. The trees over the island are, I understand, farmed out to the inhabi- 
tants, but the Sultan retains for himself a certain district. 
To the tree the inhabitants give the name “kharya,” and the resin they call 
‘‘edah.” WELLSTED* states that the Arabic name for the resin is ‘dum khoheil.” - 
One also reads that the Arabic name for it is “ katir.” 
Of the resin there are three kinds— 
(a) ‘‘Edah amsello” (WELLSTED calls it “moselle”), the tears, many of 
them an inch in diameter, as they exude. 2% Ibs. of this are said to fetch a a 
dollar. It is the purest and most valuable kind. 
(0) “ Edah dukkah” is the second best kind. It consists of the small chips 
and fragments of the tears which have been broken off in separating them from 
the tree, or by attrition. The fragments present a dull red powdery aspect. 
It sells at one dollar for 4 lbs. 
(c) “Edah mukdehah” is the cheapest kind, is very impure, and brings a 
dollar for 5 lbs. It is in the form of small flat-sided masses, and consists of 
fragments of the resin and refuse of the gatherings melted together into a flat 
cake, which is then broken up into small portions. 
We obtained a considerable supply of all these kinds of resin; and as it 
appeared a matter of some interest to have an analysis made of a authentic 
specimens, my friend Dr Dossiz kindly undertook the investigation, in which ° 
he has been assisted by Mr Henperson. They have extended their research to 
the comparative analyses of the several kinds of dragon’s blood ; and through 
the kindness of Sir JosepH Hooker, and those in authority at Kew, I have 
been able to obtain samples of most of the resins labelled dragon’s blood in the 
Kew Collection, and Mr E, M. Hoxmes, curator of the Pharmaceutical Society’s 
Museum, has kindly supplied samples of like resins in the Society’s Museum. 
* In Jour. Roy. Geol. Soc., v. (1835) 198. 
