92 Science of Plant Life 



grows in shallow water along our coasts, has been found to 

 be one of the best materials for packiag the sound-proof, 

 fire-proof, and heat-proof walls of apartment houses, factories, 

 and cold-storage warehouses. Cocain, caffein, digitalis, the 

 oils of mint and wintergreen, and other substances used in 

 medicine are derived from the leaves of plants. 



