CHAPTER XV 

 ON NETTLES, SENSITIVE PLANTS, ETC. 



Stinging nettles at home and abroad — The use of the nettle — Sham nettles 

 — Sensitive plants — Mechanism — Plants alive, under chloroform and 

 ether — Telegraph plant — Woodsorrel — Have plants nerves ? — Elec- 

 tricity in the Polar regions — Plants under electric shocks — Currents 

 of electricity in plants— The singing of trees to the electro-magnetic 

 ear — Experiments— Electrocution of vegetables. 



THE common nettle is one of our most interesting 

 British plants. It is exposed to great danger; one 

 sees it growing not only in pastures and parks, 

 but in waste places, along roadsides, and near cultivated 

 ground. Yet it is very seldom either eaten or even 

 touched. Cattle do occgisionally eat the young shoots. But 

 this is exceptional, for even in fields where there are plenty 

 of cattle great clumps of nettle luxuriate and increase in 

 size every year. 



The stinging hairs are hollow and shaped rather like a 

 narrow bulb or flask; the tip is slightly bent over and 

 rounded (not sharp) ; the hairs contain formic acid. If one 

 grasps ^the nettle or strokes it in a particular way (from 

 below upwards) the hairs are pressed flat against the stem or 

 broken, so that no wound is made by them in the skin and 

 consequently they do no harm. But if the point of the hair 

 pierces the skin, the well-known irritation is set up. That 

 is because formic acid is poured into the wound. Besides 



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