The Sleeping of the Fields 
369 
of Plants,” has observed that in autumn the cell- 
contents of the leaves 
boughs ‘‘are changed into soluble 
substances, and these are conveyed to 
the permanent parts of the plant.” 
The protoplasm, or clear jelly, dis- 
appears from the leaf-cells, and so 
do the little green grains of chloro- 
phyll which float in it. 
‘“‘T was able,’’ says Professor Von 
Sachs, ‘‘by microchemical methods, 
to follow distinctly the travelling of 
the materials (especially of the starch) 
out through the tissue of the leaf- 
stalk... 
yonng wood of the branches; and, 
into the bark, or into the 
moreover, the ash-analyses of sum- 
mer leaves, compared with those of 
autumn ones, show that the most 
valuable mineral constituents of the 
leaves, especially the potash and phos- 
phoric acid, also pass out, through 
the leaf-stalks, back into the parts 
of the bough which survive the 
winter.” 
about to fall from the 
it 
Fic. 99¢.—Leaf- 
scar of the 
horse-chestnut, 
showing the 
cork-seal stud- 
ded with the 
blackened ends 
of fibro-vascu- 
lar bundles. 
By time the leaves fall their tissues contain little else 
