254 me: s. le m. mooke's studies 



collenchyma and hard bast : latex dirty yellow : no change with 



potash. 



Arundo. Walls giving proteid reactions turn pale yellow, 

 the colour becoming slightly more pronounced on addition of 

 caustic potash. Potash and ammonia, however, will give the 

 same colour when used alone. 



Maize. Very similar to Arundo. 



JBehaviour of Tannin-solutions to some other Reagents. 



(a). Behaviour to Iodine (solution of normal strength) : 



with tannic acid a pale sherry colour ; 

 with catechu a brown sherry colour. 

 (b). To Schulze's solution : 



tannic acid — a copious dirty pink precipitate ; 

 catechu — a copious rich brown precipitate. 

 (c). To a watery solution of Methyl green : 



tannic acid — a blue-green ; 

 catechu — the green taken by the nucleus. 

 (d). To Picric Sands's blue : 



tannic acid — the normal grass-green of this dye ; 

 catechu— a yellow green. 

 (e). To Corallin-Soda : tannic acid — a pale pink ; 



catechu — a deep brilliant pink. 



Behaviour of Tannin in the Plant to other Reagents. 



(a). Iodine : Rose — a rich brown colour. 



Primrose — ditto. 



Ivy hairs — yellow, but brown when the hair is seen 

 edgewise, a greater depth of tannin thus coming 

 into view. 

 (b). Schulze's solution : Hose — pinky brown. 



Primrose — brown-pink. 

 Ivy — yellow. 

 (c). Methyl green: Eose — green. 



Primrose — green. 

 Ivy — also green. 

 (d). Picric Sands's blue : Rose — blue. 



Primrose — blue. 



4 



Ivy — yellow. 





