PRINCIPLES OF ANIMAL BIOLOGY 3 



many cases, best be recorded in the form of notes. Such notes, recorded 

 while the observations are being made, will usually be isolated state- 

 ments, often without connection with those that precede or follow. How 

 frequently such notes should be made is left to the judgment of the 

 student. They are intended solely as an aid to the memory . Obviously, 

 therefore, these disconnected notes need not repeat statements made 

 in the laboratory directions. Likewise, it is superfluous to write in the 

 notes what the drawings show equally well. Unless called for by the 

 instructor, these notes need not be handed in for inspection. 



2. Summary. When an exercise is completed, with his notes and 

 drawings before him, the student should be able to draw certain conclu- 

 sions from them, or to state the principles which they illustrate. In 

 most of the exercises, those conclusions or principles will be capable of 

 clear expression in the form of a summary. If the student is in doubt as 

 to what this summary should contain, it probably means that he has not 

 grasped the significance of the exercise, and he should ask help. How- 

 ever, not all the exercises lend themselves equally well to recapitulation, 

 and the instructor may indicate, in connection with each one, whether a 

 summary is expected. When a summary is written, it is to be handed in 

 with the drawings for inspection. 



3. Drawings form a very essential part of the laboratory records. 

 They should therefore accurately fulfill the purpose for which they are 

 made. Many of them must be detailed, not caricatures of the general 

 appearance of the object; when detail is desired frequent comparisons 

 of drawing and object must be made during the process of drawing. 

 Drawings should in all cases be analytical, that is, should represent the 

 student's analysis of the structures seen. They should, therefore, be 

 made directly from the specimens themselves. Laboratory drawings 

 should not be considered from the standpoint of art, but from the stand- 

 point of faithful analysis. Sometimes brief sketches will suffice to illus- 

 trate a specific point; but even these must not be careless. 



Special training in drawing is not presupposed, but any student can 

 attend to certain features. Always use a sharp, hard pencil. Very 

 lightly mark in the outlines and general features of the object to be 

 drawn, erasing and redrawing any parts which are out of proportion 

 or incorrect. Then carefully retrace the corrected outline leaving a clean, 

 sharp, single line. Leave no thick lines, nor double lines, nor loose ends, 

 nor gaps between the ends of lines where they do not belong. Draw 

 even small granules with complete outlines and of the proper shape and 

 relative size. If granules are actually irregular make them so. Remem- 

 ber that even minor errors offend the eye. 



Make drawings large enough to show the required details. 



Shade sparingly, and always with a definite purpose in view. Shading 

 is rarely needed. An excellent method of shading for scientific purposes 



