— 99 — 
which is completely soluble in ether; and with an alcoholic solution 
containing lo per cent of this ketone, gun cotton forms a kind of 
collodium. 
Thujone. Wallach's 55*^^ treatise^) gives a number of interesting 
particulars on compounds of the thujone series. It is a well-known 
fact that thujone Cj^qH^qO, when boiled with dilute sulphuric acid, is 
converted into an isomeric ketone QoH^^gO, isothujone, which again 
can be converted by reduction into a ketone C-^^^ H^g O, thujamenthone, 
which is isomeric with menthone and tetrahydrocarvone. Wallach 
first reports on the products formed on oxidation of isothujone, the 
ketolactone Qo-^ig^s discovered by Semmler (which this investigator, 
however, erroneously declared to be identic with the ketolactone 
C^QH-^gOg formed from thujamenthone), a ketonic acid CgH^^Og, and 
an isopropyl laevulinic acid. From the fact that the latter can be 
converted into isopropyl succinic acid, and that isothujone can be 
condensed with benzaldehyde into a monobenzylidene compound 
pointing to the presence of a — CO • CHg -group, Wallach concludes 
that the formula 
CHo 
I 
HgC-CO. C-O-CO 
I I 
(HsQgCH.CH — CH2 
which Semmler has laid down for the keto lactone C^oHigOg, 
is correct. 
The author further shows that the formula 
CO.CH2 
^•^^•^^^CH.CH.CH(CH3)2 
CH3 
accepted for isothujone, is not opposed to the behaviour of thuja- 
menthone. The treatise ends with a discussion of the relationship in 
which thujone stands to tanacetone. 
Pule gone. Some time ago Wallach has already demonstrated, 
that on treating pulegone dibromide with sodium alcoholate, pulegenic 
acid is formed; but L. Bouveault and L. Tetry^) have recently 
discovered that this acid is not the only reaction-product which is 
^) Liebigs Annalen 323 (1902), 333. 
^) Bull. Soc. chim. III. 27 (1902), 307. 
7* 
