A Study on the Dark Coloured Duramen of Ebony

1. The composition of the duramen and of the alburnum of ebony-wood have been compared with that of firwood. 2. In the duramen substances occur in the cell contents which are partly soluble and partly insoluble in alkali. 3. The substance soluble in alkali appeared to have the properties and the composition of a humic acid. 4. The “nitro”-products agreed in qualities with “nitro”- humic acid. 5. From a microscopic examination it could be demonstrated that the duramen behaved microchemically in another way than the alburnum. The lignin of the duramen has partly disappeared. 6. The humic substances in the cell contents might find their origin in the lignin that disappeared from the walls. 7. Due to the lack of good methods the determination of total humic matter did not succeed. The author wishes to express his thanks to Professor Dr. Ir. G. van Iter son Jr for his unwavering interest in these problems and for his helpful criticism and to miss Dr. Ir. A. C. Sleep for her kind help with the chemical part of this study.