1913] «S". L. Jodidi 19 



the artificial and natural products were considered by some as 

 closely related,^ by others even as identical. 



When, however, dilute acids are applied, the carbohydrates yield 

 a number of well defined intermediary products. Thus, the Poly- 

 saccharides furnish first monosaccharides, these latter yield organic 

 acids, etc. For raffinose, e. g., we have: Raffinose (melitriose)-» 

 melibiose (+ J-fructose)-»(i-glucose + galactose. The resulting 

 monosaccharides can yield, e. g., lactic acid, butyric acid, alcohol, 

 citric acid, etc., depending upon the conditions of transformation. 



So far as proteins are concerned, it was first thought that they 

 have a uniform composition and constant properties. Modern re- 

 searches revealed the fact that the various proteins have different 

 chemical composition and structure. Their gradual decomposition 

 leads (through the stages of proteoses and peptones) chiefly to 

 diamino and monoamino acids. And it is the latter Compounds 

 particularly that play a role in the formation of humin substances. 



A number of investigators^° have found that proteins when 

 treated with acids yield humus-like substances. A further study of 

 this phenomenon showed that it is particularly the diamino acid 

 lysin,^^ and the monoamino acids tryptophan^^ and ty rosin (and 

 glucosamin) that participate in the production of the melanoidins.^^ 

 Hence, it is evident that plants containing proteins rieh in tyrosin, 

 tryptophan, lysin and glucosamin radicals will, everything eise being 

 equal, yield more humus than plants poor in those Compounds. 



When pure proteins are subjected to the influence of enzymes 

 or to the activity of microorganisms, they are first hydrolyzed, 

 chiefly to diamino acids and monoamino acids. The resulting pri- 

 mary amino acids are, especially under the influence of microbes, 

 subjected to secondary changes which lead to the formation of 

 humin substances, f atty and hydroxy acids, phenols, basic substances, 



^Sostegni: Landw. Vers.-Stat., 32, 9 (1885); Andre: Bull. soc. chim. [3] 

 21, 497 (1899) ; Eggertz: Chem. Centralbl., 343 (1889). 



10 Mulder: Jour. f. pract. Chem., 21, 343 (1840); The Chemistry of Vegetable 

 and Animal Physiology, trans. by Fromberg (Edinburgh and London), 1849, p. 

 153; Schmiedeberg: Arch.f.exper.Pathol.u.Pharmakol, 39,65 (1897); Panzer: 

 Zeit. f. physiol. Chem., 33, 131 (1901). 



11 Hart: Zeit. f. physiol. Chem., 33, 355 (1901). 



12 Hopkins and Cole: Journ. of Physiol., 27, 418 (1901) ; 2g, 451 (1903). 

 ^^Samuely: Hofmeiste/s Beiträge, 2, 355 (1902). 



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