392 STATE BOARD OP AGRICULTURE. 



ever, two articles apj)eared which took up the subject from another 

 standpoint. A. Baumann^ found that certain black Russian soils, rich 

 in humus, containing but traces of ammonia, as such;, yielded a con- 

 siderable amount of it upon heating with dilute hydrochloric acid or 

 upon treatment with alkali even in the cold. He pointed out that such 

 conduct might be due to the presence of amino and amido compounds. 

 Almost simultaneously this subject was taken up somewhat more ex- 

 tensively from, this point of view by Berthelot and Andre- in the course 

 of their work on amides. They found that boiling with acids, alkali or 

 even water split off ammonia from humus. They, too, attributed this 

 to the presence of amides. A short time after this, Warington^ showed 

 the presence of small amounts of amino nitrogen in a sample of Rotham- 

 sted soil which, however, had been heavily manured. He used both 

 nitrous acid and hypobromite in his work. The presence of any con- 

 siderable amounts of amides was later contradicted b}^ Sestini,* who 

 stated that he could remove only small amounts of ammonia by boil- 

 ing with alkali. As there is probably considerable difference in the 

 composition of humus and peat from different sources, this could hardly 

 be considered conclusive evidence that such materials might not in 

 some cases contain considerable amido nitrogen. As has already been 

 shown, several experimenters failed to find nitrogen in peat and humus 

 which could be removed by treatment with alkalies. In some cases at 

 least, this was probably due to the breaking down of the amides in the 

 preliminary extraction of the humus material from the soil. Sestini 

 also demonstrated the presence of amino nitrogen by the action of 

 nitrous acid and, as had Berthelot and Andre, suggested the f>resence of 

 amino acids. Likewise, Dojarenko" found considerable quantities of 

 amino nitrogen in certain Russian soils rich in humus. Unlike the 

 other investigators, he determined the amount present quantitatively, 

 using Sachsse and Kormann's method as modified by Boehmer.*' He 

 extracted the soil with ten per cent, sodium carbonate and worked with 

 the *'humic acid" thus obtained. He found from twenty-two to seventy 

 per cent, of the total nitrogen in this to be in the amino form, from 

 five to twelve per cent, in the amido form, while the ammonia varied 

 from seventy eight hundredths to two and thirty-six hundredths per 

 cent. The ammonia was determined by distillation with magnesium 

 oxide, and the amido nitrogen by converting into ammonia by boiling 

 with dilute hydrochloric acid and subsequent distillation with magnes- 

 ium oxide. He assumed all of the amino nitrogen to be present in the 

 form of amino acids. Some years later Shorey'^ applied some of the 

 methods of protein analysis to the study of soil organic matter. He 

 pointed out that, even though we might know much concerning the 

 constitution of the compounds comprising the various groups isolated 

 from protein by this system of analysis, we know nothing concerning 

 their composition when isolated from soil. Three years later Jodidi^ 

 attempted to separate the mono- and di-amino acids in extracts of peat, 

 using phospho-tungstic acid. As Shorey had pointed out, however, 



>Ver.s. Stat. 33, 247 (1887). 



=Comp. Rend. 103, 1101: Ann. Chem. 10, 368. 



•■'Cliem. News. 55, 27 (1887). 



n'ers. Stat. 51, 153 (1899); L'Orosi 21, 1. Abs. in Exp. Sta. Rec. 10, 424 (1898). 



eVers. Stat. 50, 311, (1902). 



«Vers. Stat. 28, 247, (1882). 



7Rept. of Hawaii Ag. Exp. Sta. 1906, p. 50. 



'iJourn. Am. Chem. Soc. 22, .390 (1910). Mich. Ag. Coll. Exp. Sta., Tech. Bui. No. 4. p. 28. 



