PHANEROGAMIC LABORATORY STUDIES 243 



or inconsequential features merely. Such drawing is, of course, a 

 waste of time. The corrective is such study of the material as will 

 insure an understanding of its meaning before the drawing is begun. 

 When the essential points have been grasped, they are fixed in the 

 memory by drawing. 



It is true that drawing is a help in studying objects; for the strict 

 heed one must pay to their forms in order to represent them exactly 

 leads to the discovery of facts that would otherwise escape notice. 

 The work of the pencil serves as a score by which we keep account of 

 the degree to which the eye has exhausted the details of the object. 

 The practice of drawing thus acts as a means of increasing the power 

 of attention to the manifold separable aspects of anything we wish to 

 examine, that is, the analytical power. Yet, in general, in order that 

 the drawing may be done intelligently, a certain amount of prelimi- 

 nary study is necessary. This requires time ; but the time so spent 

 is likely to be well employed. 



The attempt has been made in this book, by brief discussions pre- 

 ceding the exercises and by suggestive questions, to direct the pupil's 

 mind toward the quarter where the most essential points are to be 

 looked for in many cases. When questions are asked they are in- 

 tended to be answered, sooner or later, in the written notes of study. 



For the record of laboratory work should consist of notes illustrated by 

 properly labeled drawings. The notes should be as full as is con- 

 sistent with time limitations. 



In examining the material, even when the desired observations may 

 be fairly well made with the naked eye, pupils should be reminded to 

 make free use of the hand lens, or the microscope lens used as such. 

 Very many things are thus rendered striking and memorable that 

 otherwise would fail of making much impression. For example, the 

 delicacy of the veining of the cotyledons of Ricinus in the embryo is 

 far better seen by aid of the lens than with the eye alone, though the 

 cotyledons themselves are well above the microscopic range. And 

 this delicate veining suggests more forcibly than the mere external 

 form of the embryo how highly organized and perfected the young 

 plant already is. 



Drawings should be in outline with little or no shading as a rule. 

 Every line should be distinct and definite, and represent an exact 

 observation made upon the object. General impressions are not 

 sought. Artistic " effects " are out of place in scientific drawings. 

 Every part should be labelled. 



Experiments. The best general manual of experiments in vege- 

 table physiology is probably that of Detmer ("Practical Plant Physi- 

 ology "), translated by Moor, published by The Macmillan Company, 

 New York, 1898. List price, $3.00. From this source the teacher 

 will gain idea^s for additions to the experiments suggested in this 



