322 NOTES 



NOTE A. 



Celltjlose (p. 5). 



Though in the text cellulose is treated as a single substance, it is there 

 suggested that the term belongs rather to a group of allied substances. These 

 differ, perhaps, rather in chemical constitution or structure than in percentage 

 composition. Among them have been distinguished '* pectocelluloses " in 

 fleshy roots, fruits, etc., " muco - celluloses " in certain seeds and fruits, 

 " adipocelluloses " in cork, " cutocelluloses " in epidermis, and " ligno- 

 celluloses " in the cell- walls of woody tissues. These last are original con- 

 stituents of these cell- walls, and not the result of chemical changes during the 

 process of thickening the walls. They apparently contain rather more 

 oxygen than pure cellulose, being compounded with certain other substances 

 which modify their chemical reactions. For example, while the purer 

 cellulose of cotton-wool turns blue when treated with chlor-zinc -iodine, the 

 lignocelluloses become yellow. 



NOTE B. 



The Recent Appreciation op Timber (p. 111). 



At the Conference on Afforestation held in a committee-room of the House 

 of Lords on June 25, 1907, Dr. Schlich brought forward statistics showing 

 that from 1890 to 1906 the average price of all imported timber had risen 

 17 per cent., while that of coniferous timber bad risen 30 per cent. 



NOTE C. 



New Aprican Timbers (p. 101). 



A variety of new tropical hardwoods have recently reached the Liverpool 

 market from Southern Nigeria, and specimens of them were exhibited in the 

 Tropical Products Exhibition of September, 1907, in that city. As full 

 mention has been made in the text of the African Mahoganies and of Iroko, 

 it is mainly necessary to refer here to several Wahiut-substitutes. Of these 

 the wood of which the Benin name is " Apopo Enwiwa,'* a species of TricUlia 

 (Natural Order Melidcem), and, therefore, in reality a Mahogany, but sold in 

 Liverpool as " African WaLiut," is one of the best. It is brown to dark- 

 brown, having numerous dark veins, but no figure, works easily, and is alto- 

 gether a very good furniture wood. " Owowe " {Alhizzia sp. ; Natural 

 Order Leguminosce), very similar to the allied " East Indian Walnut," or 

 *' Koko " of the Andaman Islands (A. Lebbelc), is dark-brown, lustrous, rather 

 coarse-grained, moderately strong, and obtainable in large dimensions. It 

 should prove valuable now that true Walnut is becoming scarce. ** Odono- 

 mokyuku " {Boswcllia Klaind ; Natural Order Burserdcece), which has also 



