18 PLANT PHYSIOLOGY 



purely pedagogical necessity of showing to the teacher that he 

 has done his work well, should learn to express forcibly and 

 vividly his results to others. Such exposition has also the great 

 advantage that it aids, as nothing else can do, to give clearness 

 and definition to the student's own knowledge and ideas of the 

 subject. He should cultivate all possible simplicity of style, 

 and employ all available devices of illustration, using words, 

 pictures, tables of figures, or graphs, according as to which is 

 the more expressive for the particular point under discussion. 

 In his elementary courses the student will have learned the 

 usual form for recording the results of his experiments, — the 

 definition of object, the description of method, the statement 

 of results, and the discussion of conclusions. But in this course 

 he should do more than this; he should learn to present his 

 materials precisely as he would to a critical audience through 

 a scientific magazine, taking as models some of the best pub- 

 lished papers accessible to him. These as a rule give first, 

 (a) a descriptive title; (b) an explanation of the status and 

 importance of the problem; (c) an outline of the development' 

 of knowledge of the subject, with references to the principal 

 literature, properly cited;* (d) a description of the methods 

 and appliances used, with a discussion of their defects and of 

 the probable sources of error; (e) the actual results observed, 

 set forth in words, drawings, diagrams, graphs, or figures, as may 

 be most expressive; (/) a summary of the results and their 

 bearing. And these expositions should all be presented in a 

 suitable and neatly kept book. The student will not be able 

 to treat all of his topics so fully, but he should make this attempt 

 with some of the most important. Needless perhaps to say, 

 these expositions by the student should be carefully criticized 

 by the teacher. 



An essential part of scientific exposition is apt illustration, 

 which in essence is simply an additional mode of expression. 



* Rules for citation of literature, formulated by a Committee of Botanists and 

 used by the principal Journals of this country, are in the Botanical Gazette, 20, 

 1895, supplement to the March number. 



