IX VEGETABLE BIOLOGY. 255 



(e). Corallin-Soda : Eose — pinky brown. 



Primrose — ditto. 



Ivy — brilliant pink. 



\f )• Borax Carmine: no colour taken up in any case, except 



that sometimes in the Primrose idioblasts a very faint blue 

 can be seen. 



On comparing this series of reactions with that which imme- 

 diately precedes, the reader will notice a close agreement in the 



behaviour of tannic acid and of Eose and Primrose tannin, while 



no less suggestive a resemblance holds between a solution of 



catechu and Ivy tannin. Now the tannin of the Bose and Prim- 



rose is iron-blueing tannin : that of the Ivy is iron-greening, like 

 catechu. 



Behaviour of the Cell-walls to these various Beagents. 



Many of the reactions mentioned under this head are perfectly 

 familiar ones. However, it is necessary to refer to them in 

 marshalling the evidence upon which are based the views here 

 maintained. 



(a). Iodine. Eose: xylem, hard bast, and cuticle distinctly 

 yellower than the other extra-xylemic tissues. 



Isoetes. Meristem walls brown ; other walls yellow. 

 Fig. Xylem brown-yellow ; hard bast pinkish red : other 

 extra-xylemic tissues pale yellow, but very faint suggestion of 

 pinkish in the collenchyma, though this last reaction may fail. 

 Latex yellow and red. 



Arundo. Walls giving proteid reactions red-brown; other 

 walls much paler. 

 Maize. As Arundo. 



(£). Schulze's solution. Eose: cuticle, xylem, and hard bast 

 yellow; collenchyma and other extra-xylemic tissues lightish 

 brown-pink. 



Isoetes. Meristem walls yellow. 



Fig. Xylem yellow: hard bast a brilliant rose-colour; rest of 

 extra-xylemic tissues a very pale pinkish, like the rose-colour 

 much diluted. 



Arundo. "Walta giving proteid reactions yellow-brown ; other 

 walls much paler. 



Maize. As in Arundo f except that colour taken is a redder 

 brown ; in bast walls and unlignified part of xylem a purple 

 appears. 



