248 ORGANIC AGRICULTURAL CHEMISTRY 



synthesis. All of this food, representing both the energy and 

 the body substance, is synthesized from the two simple com- 

 pounds carbon dioxide and water by means of the energy of the 

 sun through the agency of the chlorophyll bodies and chlorophyll. 



Fats and Proteins 



In the preceding discussion we have considered in detail 

 simply the carbohydrates. ' The cell substance, however, con- 

 tains all three of the essential organic compounds, and all three 

 of them serve together as energy food. 



Synthesis of Fats and Proteins in Plants. — Though it is 

 not absolutely proved, it is generally accepted that neither 

 fat nor protein is a direct product of photosynthesis. The 

 fact that, while the most important protein formation takes 

 place in the leaves of plants, this formation is not connected 

 with the activity of either chlorophyll or light, is evidence that 

 protein is not thus formed. The synthesis of protein in leaves 

 takes place in the absence of both of these agencies if there is 

 present in the soil an abundant supply of soluble carbohydrate 

 food together with nitrate nitrogen. 



If then, as we believe, the first product of photosynthesis is 

 carbohydrate, both fat and protein are produced from this 

 carbohydrate by metabolic change. We know that in animals 

 the metabolic conversion of carbohydrates into fat is a fact. 

 A similar metabolism in plants is entirely probable and is, in 

 fact, definitely established by experimental study of the rela- 

 tion between these two constituents. 



As fats are non-miscible with water they are unable to be 

 translocated as such in the plant sap, but it has been shown that 

 when they are in the form of fine emulsions they may be carried 

 in the sap to the reserve organs. It is probable, however, that 

 the greater part of the fat present in seeds has not been brought 

 there by translocation, but has been formed in the seed directly 

 by the metabolism of carbohydrates. In this metabolism 

 different carbohydrates may take part, for it has been shown 



