SYNTHESIS OF ALBUMINOUS MATTERS 



335 



of a certain amount of available calcic phosphate together with. 

 a salt of potassa and some available nitrogenous matter.^ 



It has been shown (p. 248) tliat some plants require more of 

 one kind of food than others ; and hence the attempt has been 

 often made to prepare exactly the special fertilizer which a given 

 crop ma^' require. 



879. Nitric acid and the nitrates. Experiments with water- 

 culture have shown that plants can derive all the combined nitro- 

 gen needed for their growth from nitric acid and the nitrates. 

 But it has also been clearly shown that there are striking differ- 

 ences in the capacitj^ which plants possess for appropriating 

 nitrogen from these compounds. Even in the common agricul- 

 tural plants there are some differences in this respect. 



880. A large number of nitrogen compounds, such as as- 

 paragin, urea, albumin, etc., have been employed in experiments 

 upon plants, but most of the results possess little interest. It 

 may be said, in general, that the so-called alkaloids (which con- 

 tain nitrogen) cannot be utilized even by the very plants from 

 which they were made.^ 



881. Synthesis of albuininoas matters in the plant. A distinc- 

 tion is made between the newl}- formed or first-formed albumi- 

 nous substances in the plant and those which have undergone 

 chemical changes in the organism, as for instance the changes 

 in germination. Two views have been held respecting the place 

 where the formation of the new pi'otein matters occurs in the 



1 The following analyses, taken from the Kepovt of the Connecticut Agri- 

 cultural Experiment Station for 1883, indicate tlie composition of a few such 

 substances : — 



For an account of the commercial prices of the available nitrogen com- 

 pounds for 1883-1884, see Report of Connecticut Agricultural Experiment 

 Station, 1885. 



2 For a short account of the bibliography of this subject the student should 

 consult Pfeffer's Pflanzenphysiologie, i., 1881, p. 242. 



