then spread uj porous plates to absorb as much oi the adhering liquid as 



possible, rhe solid whitish producl which remained was dissolved in alcohol, 

 filtered it necessary, water slowlj 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 ou1 verj well, and could then be r< moved as 

 a sohd cake from the mother liquor. It was spread on porous plates as before, 

 and the process repeated until a perfectly snow-white crystalline producl 

 remained. Eudesmol as thus obtained is exceedinglj lighl and bulky, ol a silky 

 lustre, and acicular crystals al times well developed, which when sumciei I 

 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 primarj distillation, by firsl separating the more volatile constituents in the 

 leaf, then raising considerably the steam pressure in the digester and continuing 

 the distillation lor two or three hours longer. Alter 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 r.56 , at 10 

 millimetres pressure; specific gravity at 20 = 0-988 | ; specific rotation in a. 12 

 per cent, solution oi chloroform |</|,, 4- 31-21°; refractive index at 20 = 1-516, 

 molecular refraction calculated for C I5 H 26 with one double bond = 68-07; 

 found 67-85. 



They point out that from the molecular refraction < udesmol evidently 

 contains two rings and one double bond. 



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

 170 at n 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 90 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 [«]„ + 49°; and refractive index 

 at 20° = 1-50738. 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 8o° and was identical 

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

 to 1 udesmene. 



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

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

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

 vacuo at 50 6o°, eudesmene dihydrochloride was obtained, and this when 

 puritied lioni 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 [22 1 _• \ at 7 millimetres pressure; specific gravitj 

 at 20° = 0-9196; specific rotation [#]„ 4- 54-6°; refractive index at 20° = 

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



