THE ORGANIC MATTER OF THE SOIL 



135 



Monohydroxystearic acid, 



Agroceric acid, C 2 iH 42 O 3 

 Agrosteral, C 2 2H 2 2O . H 2 O 

 Paraffinic acid, C 24 H 48 O 2 

 Lignoceric acid, C 2 4H 48 O 2 

 rhytosterol, C 26 H 44 O . H 2 O 

 Pentosan, C 5 H 8 O 4 

 Oxalic acid, C 2 H 2 O 4 

 Succinic acid, C 4 H 6 O 4 

 Sacharaic acid, 

 Acrylic acid, C3H 4 

 Mannite, C 6 Hi 4 O 6 

 Rhamnose, CeHnO 

 Salicylic aldehyde, 

 C 6 H 4 OHCOH 



Arginine, C6 

 Cytosine, C 4 H 6 ON 3 . H 2 O 

 Xanthine, C 5 H 4 O 2 N 4 

 Hypoxanthine, C 5 H 4 ON 4 

 Tysine, C 6 H 14 O 2 N 2 

 Adenine, C 5 H 5 N 5 

 Choline, C 5 H 15 2 N 

 Trimethylamine, C 3 H 9 N 

 Quanine, CH 5 X 3 

 Creatinine, C 4 H 7 ON 3 

 Creatine, C 4 H 9 O 2 N 3 

 Nucleic acid (constitution 



unknown) 

 Trithiobenzaldehyde, 



(C 6 H 6 CSH) 3 



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 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, 



