"camphenol". Orx closer examination it was, however, recognised as 
an aldehyde, and it was found possible to prove its identity with the 
camphenilanic aldehyde of the melting point 68° to 70°, produced by 
Bredt and Jagelki^) from camphene and chromyl chloride. The 
remarkable formation of this body is explained in this manner, that 
camphene adds two hydroxyls, and the camphene glycol formed appears 
in the urine combined wdth glycuronic acid, but during the decomposition 
with acids is again split up, and is converted, with loss of water, in 
the manner indicated by Bredt, into camphenilanic aldehyde. 
The examination carried on by us to ascertain in how far the 
refractive index of essential oils may be employed for the purpose of 
judging their quality and purity, a matter to which we referred about 
a year ago 2), is now approaching completion. The figures which we 
have collected on this subject, a material of a fairly voluminous 
character, will be published in another place; here, we will only state 
in anticipation, that by this systematic examination we have by no 
means been converted, and that we quietly remain on the standpoint 
hitherto occupied. We do not deny that the determination of the 
indices of refraction of fractions of essential oils may be used with 
advantage for the detection of adulterations, and we will even supply 
further proofs in confirmation thereof, but for the rest we adhere to 
our opinion, that the time-honoured factors for judging the value, 
such as specific gravity, rotatory power, solubility in alcohol etc., are 
fully sufficient to distinguish pure oils from adulterated, and good 
ones from inferior oils. 
The use of the iodine-addition as a method for testing essential 
oils has been repeatedly proposed, but the results obtained by in- 
dividual investigators have proved beyond doubt that this method is 
not suitable for the purpose of ascertaining the quality of an essential 
oil. In spite of this, the method has recently again been rescued from 
the oblivion into which it had not undeservedly fallen, by Messrs. S angle - 
Ferriere and Cuniasse, who have employed it in the analysis of 
various preparations of absinthe^) for the quantitative estimation of 
the essential oils therein contained. Now with the view of rendering 
the use of this formerly- employed method more common, and to adopt 
it as a general method for ascertaining the quantity of essential oil 
in liqueurs etc., the authors have determined the iodine-absorbing 
capacity of a whole number of essential oils which they had previously 
^) Liebig's Annalen 310 (1900), 116. 
2) Report April 1902, 82. 
^) Nouvelle metliode d'analyse des absinthes. Paris 1902, publ. by Ch. Dunod. 
Compare Chem. Centralblatt 1903. I, 543. 
