Approximately 2 grams of air-dried pruning wood powder (60 to 100 mesh) are weighed in a tared alundum crucible. The crucible an d its contents are dried to constant weight at 105° C.,-cooled, and weighed. The material is then extracted for 4 hours in a Soxhlet apparatus with a minimum boiling solution of alcohol-benzene. The solvent is removed by suction, the residue washed with alcohol by suction to remove the benzene, and then. Extracted with 400 cc. of hot water in a water bath for 3 hours, filtered, washed with hot water, then with .alcohol, and finally dried. (Washing the residue with alcohol aids in the removal of the pruning wood powder from the crucible after drying.) The dried residue is transferred to a glass Stoppard weighing bottle, and weighed to calculate the percentage of waxes, oils, protein and gums in each sample, as shown in (Table 1). Then the dried residue stirred, well mixed at room temperature and hydrolysis with 25 cc. of 72 percent sulfuric acid, and maintained at that temperature by keeping it in a bath at 20 ± 1 °C for 2 hours. The resulting, mixture is transferred to an Erlenmeyer flask, diluted with water to make a 3 percent acid solution by adding 575 ml of
water, and then boiled for 4 hours under .a reflux condenser . The hydrolyzed residue is filtered on a tared alundum. Crucible, washed free of acid by means of hot water, dried, and weighed. The lignin content (lignin %) was calculated on the basis of the oven-dry sample as shown in (Table 1).