— 27 — 
The methyl heptyl ketone produced for the purpose of comparison 
bv heating a mixture of calcium caprylate and acetate, yielded a semi- 
carbazone of the same melting point. A mixture of the two semi- 
carbazones melted at ii8°to 119°, a proof that both bodies were 
identic, and that the product isolated from clove oil was methyl 
heptyl ketone. The presence of this ketone in oil of cloves is all 
the more interesting, as it had up to the now only been found in 
rue oiU). When the opportunity arises we will return to this body, 
and then identify it further. According to our present observations 
methyl heptyl ketone reacts with some difficulty with sodium bisulphite. 
To this may possibly be attributed the fact that we detected the ke- 
tone of clove oil in fractions which had already been shaken with 
bisulphite liquor. 
In our last year's April Report 2) we discussed a new method 
(published by Verley and Bolsing) for the quantitative estimation 
of alcohols and phenols, which is based on this, that the alcohols 
(or phenols) in question are esterified in the presence of pyridine 
by means of a known quantity of acetic anhydride, and the acetic 
acid not thereby combined is titrated back. As the method was 
specially recommended by Verley and Bolsing for the determina- 
tion of eugenol in oil of cloves, we have taken this particularly into 
consideration in testing the process, and have examined on the 
one hand eugenol mixtures of known content, on the other hand 
numerous clove oils, both by this method and by the one introduced 
by Umney. We desire to state here that some considerable time 
ago w^e slightly modified Umney's method to this extent, that, 
instead of a 10 per cent, potash liquor for extracting the clove oils, 
we use a 5 per cent, soda-solution. The results thereby obtained are 
perfectly satisfactory. 
As contrasted with this, the experience obtained by us with the 
acetylation-method proposed by Verley and Bolsing is unfortunately 
such, that we are unable to confirm the statements made by these 
gentlemen as to the reliability of their method. Already with the 
artificial mixtures very important differences could be observed as 
compared with Umney's method, differences which became even more 
pronounced with the natural clove oils. 
It should be mentioned here particularly, that we, of course, paid 
the most scrupulous attention to the conditions of temperature, and 
that the errors observed cannot therefore be attributed to this. The 
^) Report April 1901, 52. — Berichte der deutsch. pharm. Ges. 11 (1901), 3. 
2) Report April 1902, 24. 
