PREFACE 



Engler and Prantl's " Die Natiirlichen Pflanzenfamilien," and last, but far from least, the 

 publications of the United States of America Department of Agriculture. 



Great advantage has accrued from the co-operation of other workers. Dr. T. A. 

 Henry, F.C.S., has contributed the sections on Gums, Resins, Dyes, Tans, and Essential 

 Oils, Mr. C. E. Jones, B.Sc, F.L.S., the section on Oils and Fats, and Mr. E. H. Wilson 

 the sections on Fruits and Vegetables. The Timber article has had the benefit of Mr. 

 J. H. Badcock's extensive practical knowledge of this subject. 



Limitations of space have prevented every plant product being included, but care has been 

 taken to deal with the more important, and it is hoped that the specialist and the general 

 reader alike will find the World's Commercial Products a useful possession. 



