One kilogram of dry finely ground vegetable ivory waste (Note 1) is added gradually to 1250 g. of 85 per cent sulfuric acid in an 8-l. (2-gallon) enameled vessel (Note 2) at such a rate as to keep the temperature at 30–35° (one to two hours). The mass is well kneaded (Note 3) and then kept at about 25° for fifteen hours (Note 4). A mixture of 1 l. of acetone-free methyl alcohol and 250 cc. of pure concentrated hydrochloric acid (sp. gr. 1.19) (Note 5) is kneaded into the soft mass, which is then transferred to a 12-l. flask. The flask is adjusted on a large steam bath (Note 6); 6 l. of absolute methyl alcohol is added; and the mixture is refluxed eight hours.

At the end of this time the mixture is cooled somewhat, and 100 g. of decolorizing carbon and 150 g. of infusorial earth or fuller's earth are added, and refluxing is resumed for one-half hour. The solution is filtered hot with suction through a Büchner funnel previously heated by blowing steam into the side neck of the suction flask (Note 7). The cake is washed with 500 cc. of hot absolute methyl alcohol. The filtration is likely to be slow unless a large funnel (30 cm.) is used. The light yellow filtrate soon begins to deposit crystals (Note 8). It is kept in an ice box twenty to fifty hours. The crystals are filtered by suction, washed with 50 cc. of absolute methyl alcohol, then with 50 cc. of dry acetone, and dried on porous plates at room temperature. The yield is 480–520 g. The mannoside is pure enough for most chemical purposes. It melts at about 170° and has a rotation in water of + 78.6°. If a purer product is desired, the mannoside may be crystallized from four parts of 80 per cent ethyl alcohol with 80–90 per cent recovery if the mother liquors are worked up. Slight acidity in the solution used in recrystallization should be carefully neutralized with ammonia. The recrystallized mannoside melts at 188–189° and has a rotation of [α]²⁰D + 80.8°.