i6o SCIENCE FROM AN EASY CHAIR 



moths which fly by night, so also there are flowers 

 which remain closed by day and open at night to attract 

 these moths, by whom their pollen is carried and their 

 fertilisation effected. The tobacco-plants of our gardens 

 are examples of these night-opening flowers, which attract 

 the nocturnal moths by their heavy perfume, and there 

 are many others. 



The movements of plants are much more definite 

 and varied than one is apt to suppose. Leaves and 

 flowers turn to or away from the sun, or to or from the 

 position which will favour a deposit of moisture ; or, 

 again, their tendrils will explore and seize upon supports, 

 enabling them to secure a hold, and so to climb. The 

 sensitive plant exhibits rapid drooping movements of its 

 leaflets and leaf-stalks when touched or subjected to 

 vibration. 



An allied plant which shows slower but definite 

 movement of its leaflets has been supposed to furnish 

 thereby prophetic indications of the weather, and even to 

 foretell earthquakes. This plant is the Abrus precatorius, 

 the seeds of which are called crab's-eyes, and are used in 

 India by jewellers and druggists as weights averaging 

 a little less than two grains. They are harmless when 

 eaten, but contain a poison called abrine, which causes 

 them rapidly to produce fatal results when introduced 

 beneath the skin. Under the name " jequerity " they 

 were introduced into this country in 1882 for the treat- 

 ment of ophthalmia. This is the plant which was cele- 

 brated, about twenty years ago, as the earthquake plant 

 or weather plant, owing to the statements of an Austrian 

 naturalist as to its marvellous powers of prophecy by the 

 movement of its leaflets statements which were care- 

 fully examined by botanists at Kew Gardens at the time 

 and shown to be devoid of justification. Earth tremors, 

 like other vibrations, cause the leaflets to move and 



