CONTENTS xi 



PAGE 



Gallic acid 204 



Reactions . . - 9 . . . . . . . 205 



Ell agic acid . . . . . ' . . . . . . . 205 



Classification of tannins . 207 



Tannins as glucosides . . .' .... . . . . 208 



Properties and description of individual tannins . . . . 209 



Pyrogallol tannins . . . .210 



Gallotannic acid . . . 210 



Extraction . , . . . . ... . 210 



Reactions . . . 211 



Detection of gallic acid in presence of gallotannic acid . 212 



Constitution 212 



Ellagitannic acid - . .' . .214 



Pyrocatechol tannins . . 214 



Catechu tannic acid 214 



Catechin . "214 



Quercitannic acid 215 



Phlobaphenes . . . 215 



Physiological significance of tannins . ... 216 



SECTION VI. PIGMENTS . . . . . . . .223 



Chlorophyll 223 



Constitution ' . . . . . 229 



Action of alkalies . , , . . 230 



Action of acid , . . . . 231 



Crystalline and amorphous chlorophyll 231 



Relationship between chlorophyll and haemoglobin . . . 234 



Extraction of chlorophyll 235 



Carotinoids or yellow pigments accompanying chlorophyll . . . 239 



Carotin 240 



Xanthophyll . ,. 241 



Fucoxanthin ... .... ... 241 



Anthoxanthins ... 242 



Flavones and Xanthones . . . . ' % 2 4 2 



Yellow colouring matters derived from flavone .... 243 



Yellow colouring matters derived from xanthone .... 244 



Properties of anthoxanthins . . . , - 2 45 



Anthocyanins 246 



Connection between anthocyanins and anthoxanthins .... 250 



Extraction of anthocyanins . 250 



Occurrence ... ... ... 251 



Properties . . 251 



Reactions ... 254 



Physiological significance . . . . . 254 



Phycoerythrin . . . , ... . . . . 256 



Preparation . . . v ...... 256 



Reactions . . ..." . . . . . . 257 



Phycophaein . . . . . ... 258 



Respiration ... .... 259 



SECTION VII. NITROGEN BASES .261 



Alkaloids . . . . ... 263 



Occurrence . . . ..... 263 



Classification . . . . . . . . 264 



