The autumn-gathered tubers and the unripe pith contain considerable proportions of an insoluble non-fermentable carbohydrate, apparently identical with inulin. This disappears almost completely from the tubers towards spring and gives way to increased proportions of the more soluble carbohydrates which are already present in the autumn tubers. In addition there appears to occur towards spring an increase in the dextrorotatory compounds of the tubers, part of which at least is believed to be sucrose. Though inulin by itself was unfermentable by yeast, a comparatively mild autoclaving was sufficient to render it fermentable without the use of acid hydrolysis. The observation of Tanret that inulin may be fermented by yeast when present in a solution of already fermenting carbohydrates has been confirmed, though not to the extent claimed by him.