56 WONDERS OF ORGANIC LIFE. 



day, or teach the pretty pimpernel when to 

 open and when to close, as the weather may 

 be congenial or the contrary ? Instinct, in our 

 sense of the word, applies not to plants. It is 

 not instinct that induces the window-plant to 

 turn its leaves to the light, but its life of irrita- 

 bility is under the influence of the solar rays. 



The example of vegetable irritability which 

 is most accessible in this country, is exhibited 

 by the barberry bush, so common in gardens 

 and shrubberies. The phenomenon is thus 

 described by sir James Edward Smith, who was 

 the first to observe it. In the flower of this 

 plant there are six stamens ; these spread mode- 

 rately, and "are sheltered under the concave 

 tips of the petals till some extraneous body, as 

 the feet or trunk of an insect in search of honey, 

 touches the inner part of the filament near the 

 bottom. The irritability of that part is such 

 that the filament immediately contracts there, 

 and consequently strikes its anther full of 

 pollen against the stigma. Any other part of 

 the filament may be touched without this effect, 

 provided no concussion be given to the whole. 

 After a while, the filament retires gradually, 

 and may again be stimulated ; and when each 

 petal, with its annexed filament, is fallen to the 

 ground, the latter on being touched shows as 

 much sensibility." 



Another singular phenomenon of organic life 

 must now be noticed — the suspension of vitality. 

 Life, it has been well ascertained, may remain 

 dormant or quiescent in organic bodies for a 



