HISTOLOGY OF MEDICINAL PLANTS BY WILLIAM MANSFIELD, A.M., PHAR.D. Professor of Histology and Pharmacognosy, College of Pharmacy of the City of New York Columbia University TOTAL ISSUE, FOUR THOUSAND NEW YORK JOHN WILEY & SONS, INC. LONDON: CHAPMAN & HALL, LIMITED Copyright, 1916, by WILLIAM MANSFIELD 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 illustrations 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 Professor Walter S. Cameron, who has rendered him much valuable aid. WILLIAM MANSFIELD. COLUMBIA UNIVERSITY, September, 1916. CONTENTS PART I SIMPLE AND COMPOUND MICROSCOPES AND MICROSCOPIC TECHNIC CHAPTER I THE SIMPLE MICROSCOPES PAGE Simple microscopes, forms of 4 CHAPTER II COMPOUND MICROSCOPES