VI 11 PREFACE 



are adapted by their character and relation to each other to carry 

 out the plant's vegetative functions. It seeks to answer in some 

 measure questions about what kind of organisms plants are; 

 how thev wrest their living from the inorganic world; and how 



j o o 



they are equipped to make satisfactory terms with their 

 environment. 



At the close of each chapter are given directions for obser- 

 vations that will afford a good foundation for critical discussion. 

 In carrying out the work as there outlined the student will become 

 familiar with the most important practices in microtechnic, 

 and he will at the same time get training in independent work 

 that will prove a significant part in his education. Chapters 

 dealing in sufficient detail with microtechnic and microchemistry 

 are given to help the student to pursue the subject beyond the 

 limits of this book, and to undertake practical work in pharma- 

 cognosy and pure food and drug investigations. 



In the illustrations much use has been made throughout the 

 book of generalized diagrams. I have found these very helpful 

 in my teaching, and I offer them here in the hope that they may 

 prove suggestive to students in correlating and interpreting the 

 details of the isolated sections with which the histologist has to 

 deal, and of service in throwing light on the operation of the 

 physiological functions. 



I must make acknowledgment of especial indebtedness for 

 substance and point of view to Strasburger's Botanisches Prac- 

 ticum, and Leitungsbahnen, Haberlandt's Physiologische Pflan- 

 zenanatomie, Pfeffer's Physiology of Plants, Zimmermann's 

 Microtechnic, Czapek's Biochemie der Pflanzen, Meyer's Grund- 

 lagen und Methoden fur die Mikroscopische Untersuchung von 

 Pflanzenpulvern, Chamberlain's Methods in Plant Histology, 

 and Winton's Microscopy of Vegetable Foods. The Bausch 

 and Lomb Optical Company have kindly supplied the cuts for 

 Figs. 127, 133, 135 and 136; and the Spencer Lens Company the 

 cut for Fig. 131. 



I am indebted to Miss Eugenie Sterling for preparing the 

 drawings for most of the illustrations, and to Mrs. Marguerite 



