CHAPTEE V. 



TISSUES REACTIONS FOR CELLULOSE, SUGAR, INULINE, 

 NITRATES, TANNIN, LIGNIN MINERAL BODIES THICK- 

 ENING OF THE CELL-WALLPITS. 



PRINCIPAL MATERIALS USED. 



Beetroot, white preferred ; fresh. 



Unripe Pear. 



Tubers of Dahlia ; fresh ; also in alcohol. 



Inflorescense of Euphorbia helioscopia; in alcohol. 



Oak-galls, fresh or dried. 



Vinca major ; stems ; fresh (or in alcohol). 



Seeds of Ornithogalum. Or twigs of Cherry-laurel. 



Date stones. 



Old stem of Pinus sylvestris ; dry or in alcohol. Also fresh twigs. 



PRINCIPAL EEAGENTS USED. 



Dilute acetic acid Sulphuric acid, 50 per cent., 66 per cent., and pure 

 Strong hydrochloric acid Aqueous logwood Chlorzinc iodine Feh- 

 ling's solution Diphenylamine (0'05 gram in 10 c.c. sulphuric acid) 

 Orcin in alcohol Phloroglucin Iron chloride Potassium bichromate 

 (10 per cent, in water) Concentrated solution of molybdate of ammonia 

 in concentrated ammonium chloride Acetate of copper Ammoniacal 

 copper-oxide Concentrated solution of chromic acid Aniline sulphate 

 Eau-de-Javelle. 



Tissues of Beetroot. We commence with the white Sugar- 

 beetroot (Beta vulgar is). 1 A small piece of tissue is taken from 

 the fleshy root, and from this is made a microscopical preparation. 

 We choose for examination a radial longitudinal section, i.e., a 

 section which is taken parallel to the long axis, and in the direc- 

 tion of the radius. This section cuts at right angles the concentric 

 rings of the root, which are visible to the naked eye. Examined 



1 Red beetroot can be used, though not so good, and the parts of the 

 section from which the red cell-sap has disappeared will be of most value. 



[ED.] 



(62) 



