Sense-Life and Sensibility 



which cannot be reconciled with that theory. He 

 used a knife with a triangular point similar to that used 

 by oculists in operations for cataract, and by means of 

 it removed the whole epidermis of a Mahonia stamen 

 without even detaching it from the flower .'^^ As these 

 skinned stamens still moved when touched, it is clear 

 that more than the epidermis is concerned. As M. 

 Dop found that such stamens on movement showed the 

 same electrical reaction that occur when animal muscle 

 contracts, it is more probable that it is the protoplasm 

 which contracts or is in some way " distressed " on 

 stimulation.^* 



Another remarkable power of plant protoplasm is 

 chemotropism, or the recognition of different substances 

 which may attract or repel motile plants such as 

 bacteria or spores. One may compare this to '< taste " 

 in the higher animals (not of course literally). One 

 interesting experiment is as follows : a quantity of the 

 actively moving male cells or antherozoids of both a 

 moss and a fern are placed in water and then two 

 vaccine tubes are introduced, filled, the one with a weak 

 solution of cane-sugar and the other with malic acid. The 

 moss sperm cells will collect in the cane-sugar and those 

 of the fern in the malic acid. But if these solutions are 

 too strong, the sperm cells not only refuse to be attracted 

 but are actually repulsed and swim away from them.-^^ 



Bacilli can detect and react to .001 per cent, solutions 

 of certain salts, concentrations so weak, that is to say, 

 that no human being could detect them. Some other 

 very interesting comparisons of their tasting powers 

 have been described by the same author.^® Nor is this 

 power confined to moving spores of algae and to bacteria. 

 Roots show the same power of turning towards or 

 away from certain substances. Roots of Leguminosae 

 will, for instance, turn and grow towards phosphates, but 



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