CHAPTER XIII 



THE INDIVIDUAL PLANT 



In the last chapter, when referring to the sense-life of 

 plants, we intentionally left out of consideration a diffi- 

 cult little question which ought to be mentioned. 



Our own bodies, and those of all animals with a con- 

 centrated nervous system, are so controlled by our will 

 that we always think of ourselves and animals as in- 

 dividuals. We transfer this idea to the higher plants, 

 who to us seem individuals also, but as a matter of 

 fact in them there is, so far as we know, no concentrated 

 nervous system, and neither brain nor will power. 



The various cells which make up a plant are neither 

 entirely free nor are they without individuality of their 

 Own. Some very interesting cases have been lately 

 described in which one almost seems to see the plant 

 rigorously sacrificing some of its members for the 

 benefit of the survivors. 



The youngest leaves or shoots are those which are 

 least specialised, and in which it seems the protoplasm 

 is least exhausted. They have more adaptability, being 

 able to suit themselves more readily to changes in climate 

 or soil conditions, or to differences in the supply of 

 moisture or sunlight. Old leaves, on the other hand, 

 are not so well able to withstand sudden and unusual 

 changes in temperature, long periods of drought or of 

 darkness.-^ This principle must not be carried too far, 

 but perhaps explains the following curious observation. 



When plants are withering or drying up the water is 

 often withdrawn from the older leaves and stems, and 

 concentrated in the young growing parts. 



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