IN several communications1 we have shown that the generally accepted reactions for the tannins are quite unreliable, with the result that the above-named test was evolved.2 The gold-beater's skin test demonstrates the tanning properties of a substance, and is given only by true tannins. Its application to the following synthetic tannins, prepared according to Enil Fischer,3 digalloyl-glycol, trigalloyl-glycerin, tetragalloyl-erythrol and hexagalloyl-mannitol, shows them to possess no tanning properties whatever. These observations thus extend my objections,4 since further emphasised by Tschitschibabin,5 to Fischer's galloyl-glucose formula of gallotannin.