KozLowsKi : Primary Synthesis of Proteids * 45 



side is the simplest formula of protein, with the omission of the 

 sulpliur. 



The equation shows that nitric acid and a carbohydrate can pro- 

 duce protein without setting free other products than those which 

 are produced by respiration, namely, carbonic acid and water. 



This reaction is otherwise represented by Berthelot and Andre, 

 whose considerations are based upon chemical researches concern- 

 ing the amount of calcium carbonate, oxalic acid and proteids at 

 different periods of life of a plant and in its different parts.* 



Comparing the formula of formic aldehyde with that of oxalic 

 acid, we see that when the latter is produced from the former 

 it w^ould have an excess of hydrogen : 



2CIip + 2Hp = qHA+H, 



If we take into consideration the equality of volumes of car- 

 bonic anhydride and oxygen by the assimilation, the surplus of 

 hydrogen shows that besides the oxalic acid a substance richer in 

 hydrogen (or poorer in oxygen) than carbohydrates is pro- 

 duced. This may be the protein. The amount of protein found 

 in the leaves of Rumex acetosa by the quoted authors answered 

 fairly well to that of the oxalic acid, as needed by such a supposi- 

 tion. The oxalic acid is to be considered as one of the products 

 oxydized, being formed as the reverse side of the reduction of 

 proteids. 



A. F. W. Schimper,f agreeing with Emmerling, that amides are 

 the predecessors of proteids, considers in accordance with the ex- 

 pressed view of Berthelot and Andre the oxalic acid as an indirect 

 product of that process and gives the following equation to ex- 

 plain the formation of amides : 



Glucose. Nitric acid. Asparagine. Oxalic acid. 



C«H,,0, + 2NHO3 = C,H,NA + C,HA + 2\l.p 4- 3O 



The three atoms of oxygen are added to the exhaled mass of 

 that element giving a little surplus over the amount of absorbed 

 CO^, which is generally observed.^ 



Comptes Rendus, loi ; 24, and 102 : 995, 1043. 

 "t Flora, 1890. (Zur Frage der Assimilation der Mineralsaltzen in der Pflanze, 



242.) 



XL. c, 260. 



