EXCREMENTS OF PLANTS. 115 



quantity of morphia is accompanied by a maximum 

 of narcotina. Not a trace of meconic acid* can be 

 discovered in many kinds of opium, but there is not 

 on this 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 ex- 

 ist, they are always found to bear a certain relative 

 proportion to one another. Attention to these facts 

 must be very important in the selection of soils des- 

 tined for the cultivation of plants which yield the 

 vegetable alkaloids. 



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

 the juice of poppies, that an organic acid may be re- 

 placed by an inorganic, without impeding the growth 

 of a plant, we must admit the probability of this sub- 

 stitution 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 fre- 

 quently in cultivated plants, because they are sub- 

 jected to special external conditions for the purpose 

 of the production of particular constituents or par- 

 ticular organs. 



When the soil, in which a white hyacinth is grow- 

 ing in a state of blossom, is sprinkled with the juice 

 of the Phytolacca decandi^a^^ the white blossoms as- 

 sume 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. f 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 



* Robiquet did not obtain a trace of meconate of lime from 300 lbs. 

 of opium, whilst in other kinds the quantity was very considerable. 

 Ann. de Chim. liii. p. 425. 



t American nightshade. 



t Biot, in the Comptes rendus des Stances de VAcaMmie des Sciences^ 

 b. Far is J ler Simestrty 1837, p. 12. 



