STORAGE OF NOURISHMENT IN THE SEED. 21 
Compare the kernel of corn and its germination with the oat, Fig. 9. 
‘28. Experiment 9. Of how much Use to the Corn Seedling is the 
Endosperm ? — Sprout kernels of corn on blotting-paper. When they get 
fairly started, cut away the endosperm carefully from several of the seeds. 
Suspend on mosquito netting over water in the same jar two or three 
seedlings which have lost their endosperm, and as many which have not 
been mutilated. Let them grow for some weeks, 
and note results. 
29. Starch. —- Most common seeds con- 
tain starch. Every one knows something 
about the appearance of ordinary commer- 
cial starch as used in the laundry, and as 
sold for food in packages of corn-starch. 
It is not always easy, however, to recog- 
nize at sight the presence 
of starch as it occurs in 
seeds, but it may be detected 
by a very simple chemical 
test, namely, the addition 
of a solution of iodine.? 
30. Experiment 10. 
Test Seeds with Iodine for 
Starch.2— Pulverize one or two 
seeds,*? add two or three drops of 
boiling water to soften and swell 
the starch, and then add, drop Fic. 9.—The Oat. I, Fruit, longitudinal sec- 
by drop, the iodine solution. tion, pr, caulicle; G, plumule; C, cotyle- 
Only a little is necessary ; some- don; A, endosperm; 7, testa; O, wall of 
times the first drop is enough. ovary. II, Germination. G, plumule ; Cc, 
If starch is present, a blue cotyledon; Col, sheath of caulicle ; R, root. 
’ 
color (sometimes almost black) will appear. If no color is obtained in 
this way, boil the pulverized seeds for a moment in a few drops of water, 
and try again. 
I i 
1 The tineture of iodine sold at the drug-stores will do, but the solution prepared 
as directed in Appendix B answers better. This may be made up in quantity, and 
issued to the pupil in drachm vials, to be taken home and used there, if the ex- 
perimenting must be done outside of the laboratory or the schoolroom, 
2 May be a home experiment. 
8 With large seeds, like a nut, only part of ong will be necessary. : 
