72 OF THE INORGANIC CONSTITUENTS OF PLANTS. 



account an absence of acid, for the meconic is here replaced by 

 sulphuric acid. Here, also, we have an example of what has 

 been before stated ; for in those kinds of opium where both these 

 acids exist, they are always found to bear a certain relative pro- 

 portion to one another. 



Now if it be found, as appears to be the case in the juice of 

 poppies, that an organic acid may be replaced by an inorganic 

 without impeding the growth of a plant, we must admit the pro- 

 bability 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 will not show themselves so frequently in 

 cultivated plants, because they are subjected to special external 

 conditions, for the purpose of the production of particular con- 

 stituents or of particular organs. 



By sprinkling with the juice of the Phytolacca decandra, the 

 soil in which a white hyacinth is growing in a state of blossom, 

 its white blossoms assume in one or two hours a red color, which 

 again disappears after a few days under the influence of sunshine, 

 and they become white and colorless as before.* The juice in 

 this case evidently enters into all parts of the plant, without 

 being at all changed in its chemical nature, or without its 

 presence being apparently either necessary or injurious. But 

 this condition is not permanent, and when the blossoms have 

 again become colorless, none of the coloring 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 potassium, nitre, or nitrate of 

 strontia ; they will enter into the different parts of the plant, just 

 as the colored juice mentioned above, and will be found in its 

 ashes if it should be burnt at this period. Their presence is 



* Biot, in the Comptes rendus des Stances de l'Acad^mie des Sciences, 

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



