HISTOLOGY 17 
the low and the high power. What is the effect of 
iodin on starch granules; on proteid granules? Is the 
proportion between starch and proteid the same in all 
cells? Study particularly those near the outer surface. 
Accurately draw three or four typical adjoining cells in 
outline as seen under the high power and represent the 
granules in one of them. 
Cut sections perpendicular to the cross sections 
already cut and study them as you did the cross sections. 
From these two series of sections you should get a clear 
conception of the form of the cells as solids. Describe 
the microscopic structure (histology) of a cotyledon of 
a pea, 
Find some starch St anule: not in the cell-cavities. 
How can they get out of the cavities? Under the high 
power study the structure of some not stained with 
iodin. Make an enlarged drawing of a typical specimen 
showing the marking in it and describe. 
Making use of the experience gained and the labo- 
ratory notes used in working out the cell structure of a 
cotyledon of a pea, study the histology of the following 
seeds: bean, corn, wheat, oats, soaked in water about 12 
hours, and sunflower 4 and castor-bean not soakea, 
and also that of a potato, which is not a seed. Make © 
drawings similar to those made in studying the pea. 
Note the relative amount of starch and proteid in each 
seed, form, relative size of the cells and thickness of the 
cell-walls, etc. In which part of each seed do you find 
most proteid; most starch? The sunflower seeds and 
castor-beans contain oil. Mount some sections of these 
seeds in water and others in glycerin. While studying 
