2 INTRODUCTION 



at the disposal of the class, that it must vary greatly with the 

 different conditions. The authors, recognizing these difficulties, 

 have tried to present a flexible outline in a thoroughly practical 

 manual containing sufficient material to permit of a wide range 

 of choice. In general they believe that the best results will 

 be obtained, when a full year can be devoted to the subject, by 

 taking the matter in the order given in the first or second of 

 the alternatives presented above. If only a half year is avail- 

 able, the best course in their judgment is that indicated in the 

 third alternative. 



For the guidance of any who may care for such suggestions the 

 authors have designated hy double asterisks (* *) those experiments 

 and studies which they consider to he the most valuable. 



A brief discussion of laboratory methods and equipment is 

 presented immediately before the laboratory outlines and experi- 

 ments of Parts I, II, and III. It is hoped that the instructor may 

 find some helpful suggestions in this, and certain parts are 

 written expressly to aid the student to an understanding of the 

 spirit of laboratory work, methods of drawing, note taking, and 

 the care of instruments. 



The essential methods of botanical microtechnique and the 

 preparation of the material are taken up after the laboratory out- 

 lines. This account has been introduced to assist the instructor 

 and the advanced student in the collection and preservation of 

 material and in the more detailed studies of plant histology and 

 cytology', which demand the preparation of microtome sections 

 and critical staining methods. The discussion does not attempt 

 to give such details covering special studies as may be found in 

 several more exhaustive treatises to which the reader will be 

 referred. It endeavors rather to outline standard methods of 

 killing, fixing, preserving, cutting, and staining plant structures, 

 which cannot fail to give good results, with the reasons why 

 they have been selected. Some simple directions for the culture 

 of algae, fungi, moss protonema, fern prothallia, etc., follow the 

 account of microtechnique. 



