PLANTS DEFEND THEMSELVES 45 



the plants hardened their blades with silica. The 

 common horsetail, a plant of this species, makes 

 deadly sick those unwise cattle and sheep which 

 attempt to eat it. 



There are many juices and poisonous secretions 

 used by plants in defending themselves against 

 animal life. One of the most common of these is 

 tannin. It is found in the bark of many trees: 

 in the beech, the walnut, the pecan, and the hickory, 

 in the tropical acacia, in several of the oaks, be- 

 neath the shells of nuts, and encasing the repro- 

 ductive germ in most fruits. 



Here once more is evidence of the reasoning 

 power of plants. Their one great aim is repro- 

 duction the perpetuation of their kind. To this 

 end all thought and action in plant life is directed. 

 It is for this reason that the winged insect, a pollen- 

 carrier, is given entree to the soul of the plant, while 

 the crawler, not a pollen-bearer, is resisted with 

 every power. To the plant mind or instinct, the 

 preservation of the fruit is nothing it is merely 

 a soft covering for the germ inside ; but the preser- 

 vation of the germ, the reproductive possibility, is 

 everything. Hence the fruit is an edible, inviting 

 thing; but the "stone" or "pit" is a hard, indigesti- 

 ble piece of "waste," which is thrown aside. Thus 

 it is provided an opportunity to germinate in new 



