SCIENTIFIC DRAWING AND DESCRIPTION 73 



these points after their own efforts have made them 

 feel the difficulties has many times more meaning than 

 it has before they have themselves tried. It is impor- 

 tant, however, not to confuse them by too many 

 suggestions at once. It is much better to point out 

 improvements in but one or two respects at a time, and 

 thus come gradually up to a high standard. The 

 earlier drawings will on this plan be incomplete, and 

 they may subsequently be brought up to the higher 

 grade, or left as a record of progress, not without its 

 value. From the first, it is necessary to insist that the 

 laboratory work shall not be made a drawing lesson. 

 The laboratory hours are for observation and com- 

 parison, and time for outline drawings only can be 

 taken ; all refinements should be added outside of 

 these hours. 



Drawing with the microscope, after the use of the 

 instrument is once learned, offers few difficulties, since 

 the objects are seen in but one plane. In drawing 

 tissues, it is a good plan to shade all walls, and leave 

 intercellular spaces and cavities blank, even in cases 

 where, as in cross-sections of bast fibres, the re'verse 

 would make a better picture of the object. Here, also, 

 diagrammatic clearness is the highest quality of the 

 drawing. 



After the first principles of scientific drawing as here 

 outlined have been grasped by the student, the teacher 

 may well give from time to time some instruction upon 



