( 624 ) 
XXVIIL—On a Red Resin from Dracena Cinnabari (Bal/f. jil.), Socotra. By 
J. J. Dosaiz, M.A., D.Sc., Assistant to the Professor of Chemistry, Uni- 
versity of Glasgow; and G. G. Hrenperson, B.Sc. 
The resin to which the following paper refers was obtained by Professor 
Baytey Batrour from a species of Dracena which he discovered in Socotra 
during his visit to that island in the year 1880, and to which he has given the © 
name of Dracceena Cinnabar. In outward appearance and in general physical 
properties the resin differs from the varieties known commercially under the 
name of dragon’s blood. With the view of ascertaining if these differences 
depend upon difference of chemical composition, we undertook, at Professor 
BaLrour’s request, to make an examination of the resin, 
The resin is in the form of large drops or tears of a deep red colour ; when 
ground it is of the same colour as some varieties of cinnabar. At ordinary 
temperatures it is brittle, and breaks with a clean fracture into transparent 
fragments which transmit rich ruby-red light. It begins to soften between 50° 
and 60° C, and melts at about 60°; when heated to its decomposing point 
it gives off aromatic and irritating fumes. The specimens given us were ex- 
ceedingly pure, leaving, after solution in ether, a residue of only 3:4 per cent., 
which appears to consist entirely of fragments of vegetable tissue. The resin is 
soluble to a slight extent in boiling water, the solution being acid. It dissolves 
entirely in alcohol, ether, and oil of cloves. The alcoholic solution is of a fine 
blood-red colour, and has a strongly acid reaction. It is atmost entirely insoluble 
in chloroform, benzene, carbon bisulphide, and petroleum ether. It contains no 
benzoic acid ; at all events it yields up no extract to petroleum ether, in which 
benzoic acid is fully soluble. Neither does cinnamic acid appear to be present, 
because, when the resin is heated to a temperature above that at which cin- 
namic acid sublimes, no trace of that acid is obtained. As much discussion has 
taken place regarding the presence of cinnamic or benzoic acid in red resins, 
we made artificial mixtures containing only 1 per cent. of these acids, in order 
to determine whether or not they can be detected by sublimation when present 
in very small quantity. On heating, in sublimation tubes, quantities of the 
mixture containing not more than one-twentieth of a grain of acid, we found 
that it could be detected with.certainty, whereas a much larger quantity of the 
resin to which no acid had been added, gave no sublimate. Again, on digesting 
the artificial mixture with benzene and with ehloroform, in both of which cin- 
namic and benzoic acids are soluble, we obtained an extract which was almost 
