46 THE BAMBOO GARDEN CHAP. 
only visible under the microscope. An illustration of a 
vertical section of a Bamboo leaf magnified 180 diameters 
is given at page 296 of Part ILI. of Kerner and Oliver's 
Natural History of Plants, together with parts of the same 
section magnified 460 diameters: this illustration clearly 
shows the whole mechanism. But the same authors 
describe a very simple experiment by which its effect 
may be seen. 
On plunging a bamboo leaf in water a surprising sight presents 
itself. The upper side, covered by a dark green, smooth, flat 
epidermis, with no stomata, becomes wet all over and retains its 
dark colour and dull appearance ; but the under surface, blue green 
in colour, and beset with stomata and thousands of cuticular pegs, 
does not allow the air to be displaced, and this layer of air, spread 
thin over the surface, ¢listens under water like polished silver! The 
leaf may be shaken under water to any extent, and may even be left 
submerged for a week, but the silvery glistening air stratum is not 
dislodged. If such a leaf is now taken out of the water, the upper 
surface is quite wet, but the under surface is dry, like a hand which has 
been dipped in mercury and then withdrawn, and not the smallest drop 
of water adheres to it. On placing a vessel of water, in which some 
bamboo leaves are half immersed, under the receiver of an air-pump 
and then pumping out the air, numerous small air-bubbles are at once 
given off from the submerged portions of the leaves. At length the 
silvery lustre disappears, and the air between the cuticular pegs is 
replaced by water. If now the leaves be completely submerged, the 
silver lustre is only shown on those parts which were not previously 
immersed, and where water could not replace the exhausted air,—the 
spaces round the pegs in this region having been again supplied with 
air on the opening of the stopcock of the pump in order to submerge 
the leaves. It may be imagined from this experiment how much 
the stomata would be damaged by water if the plants mentioned were 
not protected from moisture by the pegs to which the air adheres 
so strongly. 
A third contrivance of Nature for guarding the stomata 
of plants against excessive wet is to be found in “the hair- 
