INTRODUCTION. 



Almost every thoughtful teacher of botany in the colleges and 

 universities of our country is confronted by two problems in con- 

 nection with his laboratory instruction. He is forced to provide a 

 course which shall give the general student a fair knowledge of 

 what the teacher deems the most important phases of plant life; 

 and on the other hand, if a conscientious instructor, he will encour- 

 age students to advanced work, inaugurating courses which are 

 intended not only to inform the mind, but to train the powers of 

 observation, comparison and scientific judgment, and finally pro- 

 duce the investigator capable of pursuing problems of science 

 without aid or admonition, if not without suggestions from his' 

 professor. 



Some ten years ago, the present writer, thert in charge of the 

 Histology and Cryptogamic Botany at Cornell University, attempted 

 a revision of his laboratory course in plant anatomy, in order to 

 adapt it to the advanced courses, chiefly in Cryptogamic Botany, 

 which followed. The result was a small hand-book, privately 

 printed in 1886, entitled, "Anatomy and Histology of Plants," 

 which evidenced the author's desire to impart some special knowl- 

 edge of tissues as a foundation for more serious work in any 

 subsequent subject involving the use of the microscope. It soon 

 appeared, however, that better methods in the preparation of soft 

 tissues and delicate organisms must be adopted, if any great 

 advance was to be made toward the solution of problems of 

 structural development. 



It may here be mentioned that imbedding and cutting serial 

 sections of delicate plant tissues, had not been put in practice in 



