102 LORD AVEBURY 



XXIII 



Lord Avebury, better known as Sir John Lubbock, is 

 Lord one of the best of eye-openers. Take up the 



Avebury volume which he has recently published 

 Notes on the Life History of British Flowering Plants 

 see what he has to say about the commonest weed, and 

 it is ten to one he will add something to your store of 

 knowledge that kind of knowledge which makes dulness 

 out of the question in the country. For instance, turn to 

 what he has to say about the common stinging nettle: 

 you will find a figure representing a vertical section 

 through part of a leaf of that plant, magnified thirty-five 

 times, showing two of the stinging hairs, each seated on 

 its cushion of delicate tissue, which, when tightly pressed, 

 distils the acid fluid, causing irritation to follow upon the 

 minute wound inflicted by the hair. Each of these hairs 

 is capped with a rounded head. How, then, does it pene- 

 trate the human epidermis ? It cannot do so until the 

 head is broken off, which, as it is set at an angle to the 

 stem upon a thin neck of silicified or flinty tissue, is done 

 by the slightest touch. When the head falls off, the 

 sharp points of the fracture cause the wound. This much 

 one may learn from any work on structural botany, but 

 here is a piece of practical observation from Lord Avebury's 

 store which could not be explained without a clear know- 

 ledge of the mechanism of the plant. All the stinging 

 hairs point upwards and forwards. Touch a leaf from 

 above or from in front and you must be stung ; but you 

 may safely take it from below and behind, for then you 

 simply compress the hairs against the leaf or stem. Pro- 

 tective these hairs or needles doubtless are, but I greatly 



