84 THE WORK OF PLANTS 
Cut a piece from a fresh leatstalk* six or* eight 
inches long. Cut the ends squarely. With a knife 
remove a strip from one side, the entire 
length of the piece. Try to put it in 
place again. It is shorter than it wag 
before. Remove another strip and 
another, until the entire outer surface 
has been removed. Now try to put one 
of the outside strips in place again. It 
is now shorter than before as compared 

with the centre piece. 

You see when the outside strip was 
Hig. 119. Fortionof removed it shortened up. When all the 
leafstalk of rhu- 
arb with one strip Outside strips were removed the centre 
piece lengthened out. I think now you 
can tell why it is that the leafstalk was so firm. Of 
course it must have plenty of water in it to make the 
cells firm. But the centre piece alone, with plenty of 

FIG. 120, Strips trom outside of leafstalk of rhubarb placed in water, at left they 
s coil up, at right in salt water they uncoil. 
“If rhubarb cannot be obtained, the plant known as Caladium 
In greenhouses is excellent. Tn early summer the young soft shoots 
of elder are good for the experiment. 

