I 7 6 



AGRICULTURAL CHEMISTRY 



compounds are those which contain no nitrogen but are 

 composed of carbon, hydrogen, and oxygen. Starch, 

 sugar, and fat are types of non-nitrogenous compounds, 

 while albumin, casein, and fibrin are types of the nitroge- 

 nous. 



225. Classification of Non-Nitrogenous Compounds. 

 There are six large divisions of the non-nitrogenous com- 

 pounds : (i) carbohydrates, (2) pectose substances, (3) 

 fats, (4) organic acids, (5) volatile or essential oils, and 

 (6) mixed compounds. Each division is, in turn, di- 

 vided into various subdivisions and groups : 



f i . Carbohydrates, 

 Cellulose, 

 Starch, 

 Sugar, 

 Pentosans, 

 Gums. 

 2. Pectose substances (jellies). 



{i. Olein, 

 2. Stearin, 

 3. Palmitin, etc. 



{i. Tartaric, 

 2. Oxalic, 

 3. Malic, etc. 



5. Volatile or essential oils. 



6. Mixed compounds. 



Carbohydrates 



226. General Characteristics. The carbohydrates are 

 the first subdivision of the non-nitrogenous compounds, 

 and include the starches, sugars, gums, and cellulose and 

 pentosan bodies. They form the largest group of or- 

 ganic compounds in plants, and in many plants and food 



Organic non-nitrogenous 

 compounds. 



