CELLS. — OILS. 
41 
lavender, which, when examined as an opaque object, 
presents rows of small globular bodies of highly refrac- 
tive powers situated in the furrows of the seed. If the 
seed be dipped in alcohol, the resinous matter will be 
immediately dissolved. 
Camphor is a substance nearly allied to the volatile 
oils, differing from them in being solid at ordinary 
temperatures. It may be found in larger or smaller 
masses, in the cracks and fissures of the wood of Laurus 
camphor a, as in a specimen belonging to John Hunter, 
which is still preserved in the Museum. 
Gum is another substance, formed originally in cells, 
but subsequently separated from the plant as an excre- 
tion. The purest form of gum is that known as the 
gum arabic, produced by the Acacia vera , which is 
very soluble in water, forming a transparent solution ; 
the gum tragacanth, from the Astragalus tragacantha } 
cannot be said to dissolve, but forms a soft opaque muci- 
lage, resembling paste. 
Wax and Tallow are also found in plants, the former 
in large quantities on the surface of the Wax-palm , 
Ceroxylon andicola , whilst the latter occurs in the 
seeds of Pentadesma and Bassia, of Sierra Leone, both 
having the specific name of Butyracea. The bloom of 
the plum and the grape are also examples of wax. 
Resins abound in some plants, especially in the 
coniferous species ; they are not unfrequently contained 
in large reservoirs, termed turpentine vessels. When 
that from the common Pine is distilled, oil of turpentine 
