For the preparation of pure crystallised eudesmol from a freshly distilled Eucalyptus oil, rich in the stearoptene, the following method was adopted as being the most convenient. Constituents boiling below about 2200 C. were removed from the crude oil by distillation, and the remainder poured into shallow vessels to crystallise. The soft buttery-like crystalline mass thus obtained was then spread upon porous plates to absorb as much of the adhering liquid as possible. The solid whitish product which remained was dissolved in alcohol, filtered if necessary, water slowly added until a permanent turbidity remained, and the whole left in open vessels to crystallise. On standing thus for one or two days the eudesmol crystallised out very well, and could then be removed as a solid cake from the mother liquor. It was spread on porous plates as before, and the process repeated until a perfectly snow-white crystalline product remained. Eudesmol as thus obtained is exceedingly light and bulky, of a silky lustre, and acicular crystals at times well developed, which when sufficiently transparent polarise very well with parallel extinction.

With several Eucalyptus oils, E. camphora, E. Gullicki, E. macrorhyncha and E. virgata, for instance, it was possible to obtain the crude eudesmol during the primary distillation, by first separating the more volatile constituents in the leaf, then raising considerably the steam pressure in the digester and continuing the distillation for two or three hours longer. After standing some hours this latter distillate crystallised as a solid cake, from which the pure eudesmol was prepared as described above.