379 



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. 



CHEMICAL AND PHYSICAL PROPERTIES OF EUDESMOL. 



Semmler and Tobias (loc. cit.} give the following constants which they 

 had determined for eudesmol : melting point 78 C. ; boiling point 156, at 10 

 millimetres pressure ; specific gravity at 20 = 0-9884 ; specific rotation in a 12 

 per cent, solution of chloroform [a] D + 31-21; refractive index at 20 = 1-516, 

 molecular refraction calculated for C, 5 H 26 O with one double bond 68-07 '< 

 found 67-85. 



They point out that from the molecular refraction eudesmol evidently 

 contains two rings and one double bond. 



When eudesmol was acetylated it yielded an acetate boiling at 165 to 

 170 at ii millimetres pressure. Reduction with hydrogen and platinum black 

 gave dihydro-eudesmol, an alcohol melting at 82 and boiling at 155-160 at 

 12-5 millimetres, and the acetate from this boiled at 158-164 at 10 millimetres. 



When boiled with absolute formic acid dihydro-eudesmol gave dihydro 

 eudesmene, a body boiling at 126-130 at 10 millimetres. 



When boiled with go per cent, formic acid eudesmol was converted into 

 eudesmene, which substance boiled at 129-132 at 10 millimetres; had specific 

 gravity at 20 = 0-9204; specific rotation at 20 [] D + 49; and refractive index 

 at 20 = 1-50738. J The molecular refraction from this shows clearly that the 

 sesquiterpene contains two rings and two double bonds, and belongs to that 

 group of sesquiterpenes which is derived from hydrogenated naphthalene. When 

 eudesmol was shaken with hydrogen chloride glacial acetic acid, eudesmene 

 dihydrochloride was formed ; this substance melted at 79-80 and was identical 

 with the hydrochloride which was formed by the addition of hydrogen chloride 



to eudesmene. 



Later, Semmler and F. Risse (loc. cit.} undertook further investigations 

 with eudesmene, which they had prepared by saturating a solution of eudesmol 

 in glacial acetic acid with hydrochloric acid. On evaporating this solution in 

 vacuo at 50-60, eudesmene dihydrochloride was obtained, and this when 

 purified from alcohol melted at 70. It was then boiled with alcoholic potash 

 under a reflex, the resulting product being eudesmene, possessing the following 

 properties : Boiling point 122-124 at 7 millimetres pressure ; specific gravity 

 at 20 = 0-9196; specific rotation [] D + 54' D ; refractive index at 20 

 1-50874. When the acetic acid solution was reduced with hydrogen in the 



