CACTUS WATER BARRELS 
shape. The greater part of its inside, however, is filled 
with wet and woody pulp somewhat like the white part 
of a watermelon rind. It is a huge sponge. When an 
occasional rain comes, the roots of the cactus drink it up 
rapidly and pump it up into this inner sponge. The ac¬ 
cordion pleats of its outer covering expand. Its girth in¬ 
creases. It lays in a water supply to last months or years. 
Then it draws on that supply very, very sparingly. Its 
life depends on not reducing it so low that it will not 
carry through to the next rain. 
It is almost unbelievable that these moisture pockets 
can exist here in the burning sands. Many a desert 
traveler, however, facing death by thirst, has cut into a 
barrel cactus and found that he could squeeze enough 
water from its pulp — not too tasty, to be sure — to keep 
him alive until he could find his way out of his desperate 
plight. 
33 
