30 PLANT BIOLOGY 



tried at home. The pupil can thus make the drawings for the 

 notebook at home. A daily record of measurements of the change 

 in size of the various parts of the seedling should also be made. 

 24. Seed-testing. It is important that one know before planting 

 whether seeds are good, or able to grow. A simple seed-tester 

 may be made of two plates, one inverted over the other (Fig. 31). 

 The lower plate is nearly filled with clean 

 sand, which is covered with cheese cloth 

 or blotting paper on which the seeds are 

 placed. Canton flannel is sometimes 

 used in place of sand and blotting paper. 

 The seeds are then covered with another 

 blotter or piece of cloth, and water is 

 applied until the sand and papers are 

 saturated. Cover with the second plate. 

 FIG. 31. A HOME-MADE Set the plates where they will have about 

 SEED-TESTER. the temperature that the given seeds 



would require out of doors, or perhaps a 



slightly higher temperature. Place 100 or m(5re grains of clover, 

 corn, wheat, oats, rye, rice, buckwheat, or other seeds in the tester, 

 and keep record of the number that sprout. The result will give 

 a percentage measure of the ability of the seeds to grow. Note 

 whether all the seeds sprout with equal vigor and rapidity. Most 

 seeds will sprout in a week or less. Usually such a tester must 

 have fresh sand and paper after every test, for mold fungi are likely 

 to breed in it. If canton flannel is used, it may be boiled. If 

 possible, the seeds should not touch each other. 



NOTE TO TEACHER. With the study of germination, the pupil 

 will need to begin dissecting. 



For dissecting, one needs a lens for the examination of the 

 smaller parts of plants and animals. It is best to have the lens 

 mounted on a frame, so that the pupil has both hands free for 

 pulling the part in pieces. An ordinary pocket lens may be 

 mounted on a wire in a block, as in Fig. A. A cork is slipped on 

 the top of the wire to avoid injury to the face. The pupil should 

 be provided with two dissecting needles (Fig. B), made by 

 securing an ordinary needle in a pencil-like stick. Another con- 

 venient arrangement is shown in Fig. C. A small tin dish is used 

 for the base. Into this a stiff wire standard is soldered. The 

 dish is filled with solder, to make it heavy and firm. Into a cork 

 slipped on the standard, a cross wire is inserted, holding on the 

 end a jeweler's glass. The lens can be moved up and down and 

 sidewise. This outfit can be made for about seventy-five cents. 

 Fig. D shows a convenient hand-rest or dissecting-stand to be 



