18 GENERAL BIOLOGY 



the like put in the proper places, all solid waste deposited 

 in receptacles for that purpose, and only water or liquid 

 waste thrown into the sinks. 



Notes and Drawings 



Experience has shown that it is necessary to make accurate 

 drawings and to write a definite and careful description of 

 an animal if one is to secure a satisfactory knowledge of it. 

 The drawings should be made (on one side only) on un- 

 ruled heavy paper, or cardboard, with a drawing pencil 

 (about 3H); the notes, written on separate sheets, should 

 accompany the drawings. 



FIG. 1. 



Figs. 1 to 3 are from drawings which are correct in form, 

 accurate in structure, and satisfactory from a scientific 

 point of view. The drawings made to accompany the work 

 of this course should be in outline like the figures, since 

 shading tends to obscure rather than clarify the details of 

 structure. The drawings shown in the figures demonstrate 

 the clearness with which details are shown, even when the 

 structure is rather complex. However, it is sometimes 

 desirable to represent the texture of a part and a shaded 

 drawing will occasionally be necessary. Fig. 4 is a drawing 

 of a group of cells characterized by thick walls of rather 

 definite appearance and structure. One side of the draw- 



