A STUBBORN CANADIAN ENEMY 
It took the government itself to find out how to kill 
these roots. Being wise in the ways of plants, Uncle Sam 
developed a method of starving them to death. This is 
the way it works. 
It is the leaves of plants that prepare their food for 
them. Green leaves up there in the air and sun combine 
elements that they take from the air with those they get 
from water taken up through the roots, and thus they 
manufacture plant food. If there are no leaves, no food 
can be prepared. 
So the government decided that these roots must not 
be allowed to send up leaves. When the food was gone 
that they had stored up in themselves, they would die. 
Fields that have Canada thistle should be planted with 
some such crop as corn. This should be cultivated very 
carefully, to see that no leaves have a chance to work at 
the food making. A year, perhaps two years, of this cul¬ 
tivation will be needed to get rid of the Canada thistle. 
Since the land is no good as long as the roots are living, 
it is worth while taking such great pains to kill them. 
141 
