ii FOOD OBTAINED BY THE PLANT FROM SOIL 13 



Soluble Substances can Pass into the Roots, 

 but Insoluble Substances cannot Pass 

 into the Roots. 



Experiment 9 



Now mix a little eosine red in water and filter. 

 The eosine red dissolves and passes through the 

 filter-paper. We thus see that the eosine red which 

 we already know can pass into the roots is also soluble in 

 water. Let us then see if a colour which does not 

 dissolve can pass into the roots also. 



Experiment 10 



Take a little red lead and mix it with water and 

 filter it. The red lead remains behind on the filter- 

 paper, showing that it does not dissolve. Now mix 

 some more red lead with water and dip the roots of 

 a plant into it, as you did in the case of the eosine 

 experiment. When we look at the plant next day 

 the veins of the leaves have not been coloured red, 

 showing that the roots cannot take up the red lead 

 because it does not dissolve in the water. 



We thus see that some things dissolve in 

 water, and can then pass through filter-paper 

 and pass into the roots of the plants ; and that 

 other things do not dissolve in water, and 

 cannot pass through filter-paper or into the 

 roots of the plants. 



