, 20 FOUNDATIONS OF BOTANY 
Examine again and note the blue coloration of the starch grains and 
the unstained or yellow appearance of other substances in the field. 
Cut very thin slices from beans, peas, or kernels of corn; mount in 
water, stain as above directed, and draw as seen under the microscope. 
Compare with Figs. 7 and 8.1 Note the fact that the starch is not 
packed away in the seeds in bulk, but that it is enclosed in little 
chambers or cells. 
- 24. Plant-Cells. — Almost all the parts of the higher 
plants are built up of little separate portions called cells. 
The cell is the unit of plant-structure, and bears some- 
thing the same relation to the plant of which it is a part 
that one cell of a honeycomb does to the whole comb. 
But this comparison is not a perfect one, for neither the 
waxen wall of the honeycomb-cell nor the honey within it 
is alive, while every plant-cell is or has been alive. And 
-even the largest ordinary honeycomb consists of only a 
few hundred cells, while a large tree is made up of very 
many millions of cells. The student must not conceive 
of the cell as merely a little chamber or enclosure. The 
living, more or less liquid, or mucilage-like, or jelly-like 
substance known as protoplasm, which forms a large portion — 
of the bulk of living and. growing cells, is the all-important 
part of such a cell. Professor Huxley has well called 
this substance “the physical basis of life.” Cells are of 
all shapes and sizes, from little spheres a ten-thousandth 
of an inch or less in diameter to slender tubes, such as 
fibers of cotton, several inches long. To get an idea of 
the appearance of some rather large cells, scrape a little 
pulp from a ripe, mealy apple, and examine it first with 
~1The differentiation between the starch grains, the other cell-contents, 
and the cell-walls will appear better in the drawings if the starch grains are 
sketched with blue ink. 
