The Organisation of Matter 



fatigue. The study of vegetable fatigue is 

 greatly facilitated by the persistence of life in 

 the plant. It is thus easy to verify the fact 

 that a cauliflower or turnip stem submitted to a 

 series of identical shocks reacts less and less; 

 but a few minutes of rest are sufficient to re- 

 store their original activity. There is nothing 

 characteristic of life in all this. A platinum 

 wire behaves in the same way. Tin, on the other 

 hand, seems at first not susceptible of fatigue, 

 but if it is kept working for several days 

 running it ends like the other metals by 

 getting tired; but rest soon restores all its 

 activity. 



The muscles of the heart and certain nerves 

 present at times a typical reaction, the reverse 

 of the preceding one, called super-excitation. 

 Identical and repeated excitations produce in- 

 creasing reactions. Now Bose has observed 

 this phenomenon in plants, and even m metals. 

 A metal kept at rest for a long time seems to 

 fall into a state of indolence or torpor, and can 

 only be roused by repeated stimuli. This 

 phase of the operation is represented by diagrams 



analogous to the diagrams obtained from cardiac 



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