IO8 VEGETABLE SUBSTANCES. 



C. Of the Wall. 



THE PIGMENTS OF DYE-WOODS (Brazil Wood, 

 Sandal-Wood, etc.) 



Occur in the cell-contents as well as in the wall, 

 especially in the middle lamella, which may not 

 improbably have derived them from the former. 

 They are soluble in warm water, glycerine, acids 

 and alkalies. " Alkalies dissolve the pigments 

 very easily, with the production of a carmine or 

 violet color. Alcohol and ether give either a 

 colorless (Brazil wood, etc.) or a yellow, orange, 

 or carmine solution. Glycerine and water dis- 

 solve them with a carmine, or, less frequently, 

 with a blood-red, brownish-red, or violet color ; 

 cuprammonia, with a violet, or, more rarely, with a 

 blue color ; and acetic acid with a yellow color. 

 Sulphuric acid either does not dissolve them at 

 all (sandal-wood), or with the production of a car- 

 mine or blood-red color." x ' The coloring matter 

 of species of Pterocarpus is exceptionally insoluble 

 in hot water. 



THE COLORING MATTER OF THE BARBERRY 

 ROOT 



Is yellow, and occurs in the walls of the ducts, 

 wood-cells, medullary rays, bast-cells and the ex- 

 ternal cortical cells. It is also found in the cell- 



1 Weiss. : Allg. Bot, L, p. 137. 



