THE OBGANIC MATTER OF THE SOIL 



135 



Monohydroxystearic acid, 



CisHseOs 

 Agroceric acid, C21H42O3 

 Agrosteral, C22H22O . H2O 

 ParafSnic acid, C24H48O2 

 Lignoceric acid, C24H48O2 

 Phytosterol, C26H44O . H2O 

 Pentosan, C5H8O4 

 Oxalic acid, C2H2O4 

 Succinic acid, C4H6O4 

 Sacharaic acid, CeHgOio 

 Acrylic acid, C3H4O2 

 Mannite, CeHuOe 

 Rhamnose, C6H14O10 

 Salicylic aldehyde, 



C6H4OHCOH 



Arginine, C6H14O2X4 

 Cytosine, C4H5OX3 • H2O 

 Xanthine, C5H4O2X4 

 Hypoxanthine, C5H4ON4 

 Tysine, C6HUO2X2 

 Adenine, C5H5X5 

 Choline, C5H15O2X 

 Trimethylamine, C3H9X 

 Quanine, CH5X3 

 Creatinine, C4H70X"3 

 Creatine, C4H902X^3 

 Xucleic acid (constitution 



unknown) 

 Trithiobenzaldehyde, 



From a chemical standpoint these compounds may be 

 classified under four heads : (1) those containing carbon 

 and hydrogen; (2) those containing carbon, hydrogen, 

 and oxygen ; (3) those containing carbon, hydrogen, and 

 nitrogen, or carbon, hydrogen, oxygen, and nitrogen; 

 (4) those containing sulfur in combination with the 

 elements listed above. With the possible presence in 

 soils of compounds containing five elements, it is of 

 little wonder that the subject is a complicated one. It 

 is evident, moreover, that the list given above is only a 

 partial one, and many other compounds of an even more 

 intricate composition will later be isolated. 



So far as the plant is concerned, the compounds may 

 be divided into three groups — those that are beneficial, 

 those that are neutral, and those that are toxic, or harm- 

 ful, in their effects. As an example of the first group^ 



