APPENDIX B 265 



vi. Stained slightly or not at all by solutions of carmine, and 

 haematoxylin, but readily by aniline colours. 

 Cuticularized or Corky Cell-walls. 

 i. Coloured yellow by iodine, 

 ii. Coloured yellow or brown by chlor-zinc-iodine. 

 iii. Coloured yellowish by strong potash : on gradually warm- 

 ing (without boiling), they become bright yellow : on boiling, 

 yellow drops of suberin escape. 



iv. They resist the action of sulphuric acid, retaining their 

 clearly-marked outline. 



v. On treatment with Schulze's macerating fluid, the cuticu- 

 larized cell-walls become conspicuous : on boiling in it, their 

 substance escapes as viscid drops of eerie acid. 



vi. They are dissolved slowly by strong chromic acid, but 

 resist its action for some time. 



vii. They are not stained by solutions of carmine or haema- 

 toxylin, but are coloured by aniline stains. 



Mucilaginous Walls, resemble cellulose in many of their 

 reactions. 



i. They swell with water, 

 ii. They swell to a greater extent with potash, 

 iii. They do not stain with iodine, 

 iv. They stain pink with corallin soda. 



v. They stain red with Hanstein's aniline-violet, blue with 

 methylene blue ; some kinds of mucilage also stain with Hoff- 

 mann's blue. 



Callus is found on the plates of sieve-tubes, 

 i. It is soluble in sulphuric acid. 



ii. It is stained by Hoffmann's blue, and by haematoxylin. 

 iii. Brown by Russow's callus-reagent, 

 iv. Pink with corallin-soda. 

 v. It is largely swollen by potash. 

 Mineral Deposits in cells or cell-walls. 



A. Silica. If a tissue be ignited on platinum foil (after soak- 

 ing in nitric acid, or Schulze's macerating fluid), and the ash, 

 after being treated with acetic or nitric acid, shows an insoluble 

 residue, the residue is silica. 



B. Calcium Oxaiate occurs in the form of crystals. 



