— 39 — 
( — 1 9°)- For this reason we do not think it impossible, that 
1-camphene is perhaps also present in oil of lemon, in addition to 
I-pinene. The priority of the detection of the last-named hydrocarbon 
undoubtedly belongs to Messrs. Burgess and Child the presence 
of camphene we hope to be able to make still more probable. 
Although a whole series of bodies has been detected in oil of lemon, 
viz., d-limonene^), cymene (?)^), phellandrene^), citral^), citronellal 
geranyl acetate '^), a sesquiterpene^), octyl and nonyl aldehydes^), and 
also pinene ^^), it has not been possible to obtain a serviceable arti- 
ficial product by mixing these various substances. This is due to the 
fact that still further bodies, which have an important bearing on the 
odour, have up to now been overlooked in the e^^aminations of 
lemon oil. 
Now we have recently succeeded in detecting methyl heptenone 
in the first runnings, and terpineol of the melting point 35° (zl'-ter- 
pene-8-ol) in the last fractions of oil of lemon. For the detection 
of methyl heptenone, the fraction consisting of terpenes, fatty alde- 
hydes, and citral, was shaken for some considerable time with bisulphite 
solution. From the crystalline bisulphite compound separating out in 
abundance, the aldehydes were liberated by sodium carbonate with the 
application of heat, and were driven over with water vapour. The 
mixture of aldehydes isolated from the distillate, passed over between 
174 and 215°, and that in the following fractions: 
I. 174 — 179°; 2. 179 — 200°; 3. 200 — 215°. 
Of these fractions, the first had a very pronounced odour of methyl 
heptenone, the second specially of octyl and nonyl aldehydes, and the 
third almost exclusively of citral. When it was attempted to obtain 
the semicarbazone of methyl heptenone from the first fraction, at first 
no solid derivative separated out. Only after the reaction-mixture 
(still strongly smelling of methyl heptenone) had been treated with water 
^) Mr. Parry, who uses his influence so much on behalf of the above-named 
gentlemen (The Chemist and Druggist 60 (1902), 866) will no doubt welcome the 
confirmation of this fact with special satisfaction. 
2) Wallach, Liebigs Annalen 227 (1885), 290. 
^) Bouchardat and Lafont, Journ. de Pharm. V, 27 (1893), 49. 
^) Report October 1897, 26. 
^) Bericht, October 1888, 17. 
^) Doebner, Archiv d. Pharm. 232 (1894), 688. — Berliner Berichte 27 
(1894), 352. 
^) Umney and Swinton, Pharm. Journ. 61 (1898), 196 and 370. 
^) Oliveri, Gazz. chim. ital. 21, I (1891), 318. 
^) V. So den and Rojahn, BerUner Berichte 34 (1901), 2809. 
Burgess and Child, Journ. Soc. chem. industr. 20 (1901), 1176; comp. 
Report April 1902, 33. 
