44 KozLOWSKi : Primary Synthesis of Proteids 



esis ; but concerning the first reaction it may be remarked that 

 while the given construction could be applied to the fungi, which 

 can assimilate ammonia as easily as other nitrogen compounds, it 

 could not apply to green plants, or at least to the phanerogams, 

 since we know that they receive not only their nitrogen in the form 

 of nitrates, but we have also certain data indicating the nature of the 

 first transformation of these nitrates. And this is the only point 

 in the whole process on which experimental researches have thrown 



some light. 



The purely chemical investigation of A. Emmerling* has shown 



that oxalic acid can decompose very dilute solutions of potas- 

 sium or calcium nitrate by combining with the base and setdng 

 free the nitric acid.f The most interesting consequence of this 

 fact is the behavior of the oxalic acid in the presence of nitrate 

 of potassium and carbonate of calcium. Pure oxalic acid does not 

 dissolve calcium carbonate, because of the formation of thin in- 

 soluble layers of calcium oxalate, which preserves it from the ac- 

 tion of the acid. But as soon as we add a small quantity of ni- 

 trate of potassium it is decomposed, and the nitric acid, set free, • 

 dissolves the calcium oxalate, producing calcium nitrate, which 

 is again decomposed by the prevailing mass of oxalic acid. Thus 

 a small quantity of potassium nitrate can by its ferment-like action 

 assist in dissolving a large amount of calcium carbonate. 



Thus the observation of Schimper concerning the disappearance 

 of nitrates in the green cells of leaves and the simultaneous accu- 

 mulation of crystals of calcium oxalate, lead to the conclusion 

 that the first change to which nitrates are exposed in leaves con- 

 sists in setting free the nitric acid. 



The nitric acid ought then to be the starting point of our 

 construction. Such a reaction is presented in the hypothetical 

 equation of A. Mayer, which represents this reaction : 



A carbohydrate. Protein without sulphur. 



C3JLP3, + 6HN0,= 2C,,H,,N30,-f 21HP -f 13CO, 



The first member of this equation is a multiple of CH,0 — the 

 simplest formula of carbohydrates ; the first number of the right 



* Landwirtsch. Versuchsstationen, 34 ; 109. 



|R. A. Wood has proved the same for pure water (Amer. Chem. Journal, 1895). 



