212 AGRICULTURAL CHEMISTRY 



water. Arrange apparatus as shown in Fig. 80. Apply heat and 

 distil 3 to 5 cc. Observe odor of distillate which is the volatile oil 

 of tea. Repeat this experiment, using sweet or red clover. 



288. Miscellaneous Compounds of Plants. Not all 



of the non-nitrogenous compounds present in plants are 

 included in the subdivisions : carbohydrates, fats, organic 

 acids and essential oils. The most important and more 

 common ones are, however, included in the above list. 

 There are a great many others which, for convenience of 

 classification, are called miscellaneous or mixed com- 

 pounds. 



289. Relationship of Non-Nitrogenous Compounds 

 of Plants. A marked general relationship exists between 

 many of the non-nitrogenous compounds. For example, 

 the various carbohydrates are capable of undergoing 

 chemical changes in which one form is changed to 

 another. Starch can be converted into cellulose, sucrose, 

 maltose or any other carbohydrate, and conversely cellu- 

 lose can be converted into starch or other similar com- 

 pounds. These changes take place during plant growth, 

 particularly in the germination of the seed, and are 

 brought about by the action of ferment bodies which 

 cause either the addition or elimination of water from the 

 molecule, as . 



2C 6 H 10 5 + HP = C,H 2 A,. 



Not all of these reactions can take place in the laboratory. 

 Starch may be changed to glucose or maltose, and sucrose 

 may undergo inversion and form invert sugars, but 

 sucrose cannot be made in the laboratory ; neither can 

 starch or cellulose be made from glucose. During 



