14 THE HUMAN SIDE OF TREES 



of methods and devices to protect themselves 

 against their enemies, but occasionally there is a 

 concerted move by an entire group or community 

 which looks extraordinarily like the exercise of 

 police power. When we find certain trees in a 

 tropical forest surrounded with a wall of particu- 

 larly thorny underbrush, it rather looks as though 

 they were definitely warning certain types of de- 

 structive animals away. When the persimmon tree, 

 once so common to the western prairies, finds it 

 best to hide itself almost entirely underground or 

 in trenches to prevent being destroyed by hungry 

 beasts, it seems as if a brain power were at worl> 

 among the plants. Certain other trees exhale 

 poisonous gases. The Germans use the seed of the 

 sabadilla, botanically known as Schoenocaulon of- 

 ficenali, for the manufacture of the lachrymatory 

 and asphyxiating gases stored in "weeping bombs." 

 The seeds of this strange and interesting plant are 

 in form and colour like oats, and when stored they 

 emit a piquant smell so strong as to make the eyes 

 water copiously; they also make breathing very 

 painful. These gases are equally painful to animal 

 and insect, and it can unquestionably be said that 

 the plant is using a police if not a military measure. 

 Plants like the gas plant exhale gas all the time 

 thus the name. 



