CHEMICAL CONSTITUENTS OF THK SOII, 157 



greater or less quantity, in the soil, and the student of soil 

 chemistry must bear this possibility in mind. 



Organic Compounds Isolated. Chemical study of the organic 

 matter of the soil has rendered probable the existance of a number 

 of organic bodies in the soil. The organic compounds claimed to 

 be isolated, so far, make up only a comparatively small percentage 

 of the total organic matter. 



Schreiner and Shorey 1 claim to have isolated sixteen com- 

 pounds. 



Hydrocarbons. Hentriacontane C 3 H 64 from a North Carolina 

 soil. 



Acids. Dihydroxystearic acid C 1S H 36 O 4 and picoline carboxylic 

 acid C 3 H 7 O, 2 H from several soils. Paraffinic acid C 24 H 48 O,, and 

 monohydroxystearic acid C 18 H 36 O 3 , lignoceric acid C, 4 H 48 O.>, 

 agroceric acid C 21 H 42 O 2 and resin acids from individual soils. 



Glycerides. Glycerides of fatty acids identified in one soil and 

 probably present in several soils. 



Wax Alcohols. Phytosterol C 26 H 44 O.H 2 O and agrosterol 

 C C H 44 O.H 2 O from individual soils. 



Nitrogenous Compounds. These are chiefly bases, and form 

 salts with acids. Arginin, cytosine, xanthine, and hypoxanthine, 

 were claimed to be isolated from several soils. 



Pentosans. The presence of pentosans in the soil was demon- 

 strated by de Chalmot 2 and others and confirmed by Schreiner 

 and Shorey. In ten soil samples, pentosan carbon made up 1.30 

 to 28.5 per cent, of the total carbon. 



Ether Extract? The soil gives up about 0.02 per cent, material 

 to ether, and about the same quantity to chloroform following the 

 ether. The ether extract consists of fatty acids and wax alcohols, 

 such as are found in plants. 



Significance of the Organic Compounds. As stated above, the 

 organic compounds mentioned make up only a very small fraction 

 of the total organic matter of the soil. The bulk of the organic mat- 



1 Bulletins 53 and 74, Bureau of Soils. 



2 Am. Cliem. Jour., 1894, p. 229. 

 * Texas Bulletin, 157. 



