HEARTVVOOD OF CRYTOMERIA JAPONICA 



859 



Now let us turn our attention to the nature of the auxochrome and 

 its derivation. It has already been shown by Dixon " that the sap 

 of wood contains a good deal of electrolytes, i. e., free ions. The 

 auxochrome under discussion is also the hydroxyl component of the 

 unknown electrolytes. But such a strong basic reaction as is noticeable 

 in the darkening of "black wood" is seemingly to be attributed to am- 

 monia; we carried out therefore the following chemical tests for the 

 identification of ammonia, taking the materials in the form of sawdust: 



(I) Distillates from "black wood" were absorbed in sulphuric acid. 

 This solution gave rise to yellow brown deposits with Nessler's 

 solution. 



(II) The application of strong alkali or magnesia to the distillation 

 resulted in the rapid evolution of ammonia and increased the quantity 

 of the above deposits. 



(III) Two microchemical methods proposed by Molisch ^'^ for the 

 identification of ammonia gave affirmative results. 



These experiments seem to prove that the alkaline reaction attended 

 with the darkening is induced by ammonia usually produced as the 

 final decomposition product of proteids. To investigate indirectly the 

 comparative distribution of proteids and amino acids (the direct de- 

 composition product of the former) among the kinds of wood and 

 ♦■he parts of the wood, we made a colorimetric comparison of the saw- 

 dust distillates, based on the intensity of the color reaction with Nes- 

 sler's solution. The material was then treated with magnesia and 

 distilled ; and the ammonia so driven oft was absorbed in sulphuric 

 acid, giving the following results : 



TABtE 6. 



Source of sawdust. 



This result shows that the heartwood of "black wood" can surpass 

 the sapwood especially that of "red wood" in the production of am- 



^^ Dixon, H. Transpiration and the Ascent of Sap in Plants, London, 1914. 

 "Molisch, H. Microchemie, Jena, 1913, p. 60. 



