CONTENTS. 

 I. INTRODUCTION. 



PAGE 



Lichens, Algae, Tree Bark and Certain Tubers and Foodstuffs 253 



II. HISTORICAL PART. 



Introduction 259 



Cellulose 262 



(a) Occurrence and Nature 262 



(b) Occurrence of Cytases (Cellulases) 264 



(1) In the Vegetable Kingdom 264 



(2) In Lower Animals 266 



(3) In Higher Animals 267 



(c) Digestion and Utilization 268 



(1) By Animals 268 



(2) By Man 269 



The Pentosans 272 



(a) Occurrence and Nature 272 



(b) R61e in Plant Physiology 274 



(c) Occurrence of Pentosanases 275 



(1) In the Vegetable Kingdom 275 



(2) In Lower Animals 276 



(3) In Higher Animals 276 



(d) Digestion and Utilization 278 



(1) By Animals 278 



(2) By Man 278 



The Galactans 282 



(a) Occurrence and Nature 282 



(b) Occurrence of Galactanases 284 



(1) In the Vegetable Kingdom 284 



(2) In the Anhnal Kingdom 285 



(c) Digestion and Utilization by Animals and Man 285 



The Mannans 289 



(a) Occurrence and Nature 289 



(b) Occurrence of Mannanases 291 



(1) In the Vegetable Kingdom 291 



(2) In the Anhnal Kingdom 292 



(c) Digestion and Utilization by Animals and Man 293 



The Levulans 295 



(a) Occurrence and Nature 295 



(b) Occurrence of Levulanases 296 



(1) In the Vegetable Kingdom 296 



(2) In the Animal Kingdom 297 



(c) Digestion and Utilization by Animals 297 



249 



