PREFACE TO THE THIRD EDITION 



The author has first endeavored to present in a clear, systematic 

 way those fundamental principles of structural and taxonomic 

 botany which serve as a key to the approach of pharmacognic 

 problems. But he has not been unmindful that the use of the work 

 has extended to academic institutions and, so, in this edition, has 

 broadened the scope of the former text. To this end about ninety 

 additional pages of subject matter have been introduced. Several 

 old cuts have been removed. Forty-three new ones have been in- 

 serted. Hypothetical discussions have been avoided which saves 

 time for the reader. 



The arrangement and plan of the chapters are similar to that of 

 the former edition, in order to adapt the work to several methods of 

 approach. Chapter I on " Fundamental Considerations" has been 

 augmented by treatises on Botanical Nomenclature, Farafrme and 

 Celloidin Imbedding, Sectioning, Staining and Mounting, Micro- 

 tomes and other information dealing with the preparation of materials 

 for microscopic examination. 



Ten pages have been added to Chapter V on Cytology. Under 

 "Protoplasm and its Properties," six pages have been written on 

 the subject of Irritability and Irritable Reactions. Under "Non- 

 Protoplasmic Cell Contents" several additional commercial starches 

 are discussed and two original plates on starch grains added. Addi- 

 tional cuts on Collenchyma, Stone Cells, Sclerenchyma Fibers, 

 Trichomes and Fibrovascular Bundles have been inserted in Chapter 

 VI. 



Nine additional pages of subject matter and illustrations have been 

 added to Chapter VII. Original figures of all of the important 

 types of fruits appear here for the first .time. 



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