ELECTRIC EXCITATION BY PLANTS. 197 



If a body absorbs carbonic-acid gas and gives 

 out oxygen, it belongs to the vegetable kingdom ; 

 if it absorbs oxygen and gives out carbonic-acid 

 gas, it belongs to the animal kingdom. In this 

 way the difference is tested. 



Becquerel says that electric currents may be ac- 

 tually detected between the parts about the stems 

 and the opposite parts of various kinds of fruit. 



" Certain vegetable organizations, especially those 

 of an orange color, such as the mangold, orange 

 lily, monkshood, and indian pink, emit at inter- 

 vals of several minutes two or three flashes of 

 light in quick succession ; and when several flow- 

 ers in the same place emitted their light together, 

 it could be seen at a considerable distance. This 

 phenomenon was noticed in July and August, 

 when the sky was clear." 



There is no doubt that light is emitted by many 

 fungi while germinating, and in -some cases to a 

 very considerable extent. An authentic instance 

 is recorded, in Gardner's " Travels in Brazil," of a 

 fungus which grew on the decaying leaves of a 

 dwarf palm. " The whole plant gives out at night 

 a bright phosphorescent light of a pale greenish 

 hue, similar to that emitted by the larger fire-flies. 

 The light given out by a few of these fungi in a 

 dark room was sufficient to read by." ] 



" No phosphorescence is perceived in the dead 

 plant." Pouillet also proved experimentally that 



1 Carpenter's Physiology. 



