THE FEELINGS OF PLANTS 



1023 



flabby and is no longer able to suj:)p(Mt the 

 leaf-stalk. Thus the organ falls by its 

 own weiglit. After an interval the water 

 in the cells regains its original distribution 

 and the leaf assumes its normal position. 



It is only during the period of active 

 growth that the Sensitive Plant exhibits 

 great susceptibility. Moreover, a high 

 temperature seems to be an essential 

 feature of a prompt re- 

 sponse to touch on the part 

 of the specimen. Up to 

 a certain point the Sen- 

 sitive Plant seems to be 

 able to become accustomed 

 to shock. A curious ex- 

 periment was conducted 

 many years ago in whicli 

 a young specimen of the 

 plant was placed in a car- 

 riage. Directly the vehicle 

 started to move the plant 

 di'ooped its leaves, but as 

 the movement continued, 

 the effects of the shock 

 became less and less until 

 something like a normal 

 position was assumed. 



Certain plants are curi- 

 ously responsive to elec- 

 trical influence. One of 

 the most remarkable of 

 these cases is that of the 

 A briis precatorius, an Indian 

 leguminous plant. The 

 behaviour of this species 

 has given rise to a good 

 deal of speculation from 

 time to time, and it has 

 been claimed that warnings of the ap- 

 proach of magnetic storms and electrical 

 disturbances may be gathered by a close 

 observation of the position of its leaflets. 

 This is certainly crediting the plant 

 with powers which it does not possess, 

 although there is no doubt that the 

 Abrus is responsive to the variations 

 in illumination, temperature, etc. It 

 is doubtful whether the plant is more 

 sensitive in this way than the Mimosa. 

 A young specimen, which the writer 

 had in his possession, evinced con- 

 siderable leaf agitation during the pro- 

 gress of a thunderstorm. Almost all 

 these sensitive plants arc very much 

 affected when exposed to the vapours of 



an anresthetic ; in this instance the foliage 

 assumes the position which it takes up at 

 night. 



The Telegraph Plant {Dcsmodiitm 

 gyrans), has well been called one (jf the 

 most curious in the world. Certainly it 

 ])rcsents a problem which has completely 

 baffled all scientists. The leaves of 

 this species are divided into three parts, 



VENUS FLY-TRAP, SHUT. 



consisting of a large leaflet and two smaller 

 lateral ones. It is these latter which 

 offer a strange phenomenon, and one 

 which is not at all easy to explain. 

 Practically throughout the whole of their 

 existence these leaflets are in motion, 

 executing little jerks, which suggest the 

 movements of the seconds hand of a 

 watch. When one of the leaflets rises the 

 other descends, each in its turn describing 

 a kind of elliptical course. 



These movements occur throughout the 

 life of the plant, although the greatest 

 activity is evidenced by the leaflets during 

 humid days when they are under the 

 influence of bright sunshine. The dura- 

 tion of each movement varies from about 



