INTRODUCTION. 3 



needles (made by inserting the eye end of a needle in a 

 stick about the size of a lead-pencil) ; a magnifying-glass 

 (a simple lens of about one-inch focus) ; a dissecting-pan ; 

 a jar of alcohol (70$) ; a note-book, pencils, and drawing- 

 paper. As the animals to be dissected are small, the 

 instruments should be of moderate size, delicacy being 

 preferable to strength. The dissecting-pans (preferably of 

 copper) should be about 6 by 12 inches, with flaring sides 

 an inch and a half in height. The bottom should be 

 covered to about one quarter of an inch in depth with 

 wax, so that the specimen may be pinned out during dissec- 

 tion. For most purposes it is better if the wax be black- 

 ened by lampblack.* At the close of each dissecting 

 period the specimen should be placed in the jar of alcohol 

 for preservation until the next time. For this purpose the 

 three-pound glass butter-jars with screw-tops are good. 



The pencils should be hard (6H, Faber), and the points 

 should be kept sharp with a file or emery-paper. For 

 drawings a smooth, hard-surfaced unruled paper is best, 

 Bristol-board, aside from expense, being preferable. The 

 drawings should be in outline only; shading should not 

 ~be attempted. Frequently the use of colored pencils will 

 make the sketches more intelligible, and for this purpose 

 the following conventional colors may be suggested : 



Arterial circulation, red. Venous circulation, blue. 



Alimentary canal, brown. Liver, green. 



Kidneys, purple. Keproductive organs, yellow. 

 Nerves, gray. 



The laboratory should be provided with an oil-stone for 



* Instead of wax, the cheaper ozokerite (to be obtained of wholesale 

 druggists) may be used. 



