102 OF THE INORGANIC 



of this substitution taking place in a much higher 

 degree in the case of the inorganic bases. 



When roots find their more appropriate base in 

 sufficient quantity, they will take up less of another. 



These phenomena do not show themselves so 

 frequently in cultivated plants, because they are 

 subjected to special external conditions for the 

 purpose of the production of particular constituents 

 or particular organs. 



When the soil, in which a white hyacinth is 

 growing in the state of blossom, is sprinkled with 

 the juice of the Phytolaca decandra, the white blos- 

 soms assume, in one or two hours, a red colour, 

 which again disappears after a few days under the 

 influence of sunshine, and they become white and 

 colourless as before*. The juice in this case evi- 

 dently enters into all parts of the plant, without 

 being at all changed in its chemical nature, or with- 

 out its presence being ^apparently either necessary 

 or injurious. But this condition is not permanent, 

 and when the blossoms have become again colour- 

 less, none of the colouring matter remains ; and if 

 it should occur, that any of its elements were 

 adapted for the purposes of nutrition of the plant, 

 then these alone would be retained, whilst the rest 

 would be excreted in an altered form by the roots. 



Exactly the same thing must happen when we 

 sprinkle a plant with a solution of chloride of 



* Biot, in the Comptes rendus des Seances de 1' Academic des Sciences, 

 a Paris, ler Semestre, 1837. p. 12. 



