REPOSE, OR SLEEP. 95 



This condition is very different from that 

 quiescence which takes place after disturbance 

 of the ultimate molecules of inorganic matter, 

 according to the laws of chemical attraction 

 and repulsion ; nor can we compare it to the 

 stillness of matter, after the cessation of physical 

 agitation ; although in figurative or poetical 

 language, we say of the ocean, or the lake 

 unruffled by the wind or the current, that it is 

 asleep. 



By the sleep of plants we do not mean that 

 change which takes place in so many on the 

 approach of winter, when the sap ceases to 

 circulate, and the foliage falls and withers ; 

 this state appears to us to belong to another 

 condition, termed hybernation, experienced by 

 many animals as a means of preserving life, 

 when all supplies of food fail. We allude to a 

 series of phenomena exhibited by plants when 

 in their full vigour, proving, apparently, that 

 they undergo periodical repose, generally during 

 the night ; although, as in the case of certain 

 animals, some are awake only during the hours 

 of darkness. It is well known that the blossoms 

 and leaves of many plants become folded up as 

 evening closes ; in the tamarind tree, and in 

 some leguminous plants with pinnated leaves, 

 natives of Egypt, similar phenomena present 

 themselves. It was not, however, until Lin- 

 naeus called attention to the subject that any 

 definite observations had been made relative to 

 the phenomena in question. Accident led him 

 to a train of experiments. He had sown some 



