This is indeed the source. I don't have a copy of Duplais to hand at present but if you will accept a passage from Bedel's Trait complet de la fabrication des liqueurs et des vins liquoreux dits d'imitation Paris, 1899, (which many people think was largely a rehash of Duplais) I can email or fax it to you. I fear that I may try the forum's patience as well as my own typing accuracy if I copy out passages of 19th century French distillers handbooks! However, when Duplais wrote the original work in 1855 no one considered thujone an issue and there would have been no way of measuring it with any accuracy if anyone had had the inclination to do so. Duplais was interested in distillation and producing liqueurs and eaux de vie so he quoted figures for g/l of essence of wormwood but not concentrations of thujone. Mistakes such as this are not as uncommon as you might think and the fact that it has not been picked up sooner is partly an indictment of scientific and journalistic technique and partly due to the fact that Duplais's book is rather hard to come by. This is indeed possible and rigorous testing would be necessary to completely eliminate this possibility. On the weight of evidence I still believe that thujone is stable in alcoholic solution, however I do need to test more samples. Indeed, just as you don't seem to see many old vins ordinnaire at auction, bog standard absinthe is also unseen. I will certainly be looking at the other topics on the forum.