264 



APPENDIX TO PART I. 



imparts to them the solidity of texture which woody fibre 

 possesses. 



''He has succeeded in isolating the two by chemical 

 means, and has found, that whilst the cellular matter has 

 exactly the same composition as starch, being composed 

 of 44*9 carbon, 6*1 hydrogen, 49 oxygen, or 44*9 carbon 

 and 55*1 of water; the incrusting matter afterwards formed 

 consists of 53'76 carbon, 40.2 oxygen, and 6 of hydrogen, 

 or of 5376 carbon, 45-2 of water, and 1 of hydrogen.^ 



''The composition of the ligneous matter of different 

 kinds of wood will therefore vary according to the relative 

 proportion of these two ingredients, as is shown in the 

 following table of M. Payen : — 



**This then proves, that, in the formation of the matter 

 which incrusts and fortifies the walls of the cellular tissue 

 in wood, though not in that of the cellular tissue itself, a 

 decomposition of water must have taken place ; since the 

 1 per cent, of hydrogen which Payen has found in excess, 

 can only have arisen in this manner. 



*'This increase of hydrogen becomes still greater, when, 

 in the progress of vegetation, the plant begins to secrete 

 oils, camphors, and other analogous bodies, products, 

 which, it is to be remarked, abound most within the tropics, 

 where the light of the sun is most intense. 



'* Hence the decomposition of water, no less than that 

 of carbonic acid, seems due to solar influence, and accord- 

 ingly, the greater sweetness of subacid fruits, in a warm 

 than in a cold summer, arises from the transformation of 

 a larger amount of tartaric or other vegetable acids into 

 sugar, owing to that separation of oxygen from the former 

 which is accomplished by the agency of light. 



*'The process of assimilation of plants in its most simple 



" * Payen has since stated, that this incrusting matter probably con- 

 sists of two or three different principles." 



