sy) 
NEW YORK B&TANICAL. 
PREFACE 
THE object of the book is to provide a practical scientific 
course in vegetable histology for the use of teachers and students 
in schools and colleges. 
The medicinal plants are studied in great detail because 
they constitute one of the most important groups of economic 
plants. The cells found in these plants are typical of the cells 
occurring in the vegetable kingdom; therefore the book should 
prove a valuable text-book for all students of histology. 
The book contains much that is new. In Part II, which is 
devoted largely to the study of cells and cell contents, is a new 
scientific, yet practical, classification of cells and cell contents. 
The author believes that his classification of bast fibres and 
hairs will clear up much of the confusion that students have 
experienced when studying these structures. 
The book is replete with illustrations, all of which are from 
original drawings made by the author. As most of these illus- 
trations are diagnostic of the plants in which they occur, they 
will prove especially valuable as reference plates. 
The material of the book is the outgrowth of the experience 
of the author in teaching histology at the College of Pharmacy 
of the City of New York, Columbia University, and of years 
of practical experience gained by examining powdered drugs in 
the laboratory of a large importing and exporting wholesale 
drug house. 
The author is indebted to Ernest Leitz and Bausch & 
Lomb Optical Company for the use of cuts of microscopic 
apparatus used in Part I of the book. 
The author also desires to express his appreciation to Pro- 
fessor Walter S. Cameron, who has rendered him much valuable 
am WILLIAM MANSFIELD. 
CoLuMBIA UNIVERSITY, 
September, 1916. 
