The Organic Acids of Rhubarb (rheum Hybridum)*

“General pronouncements on the significance of the plant acids are at present probably of little value. . . The true significance of the acid metabolism of plants may perhaps lie close to Kostytchev’s later point of view that these acids are the building stones from which some of the complex plant products originate. . . The plant acids are possibly convertible into amino acids and proteins, complex products such as the alkaloids, and by reduction into the parent substances of the fats and also into carbohydrates. Thus they may form some essential links in the processes by which the energy of respiration is transferred to the varied synthetic activities of the plant. It is certainly clear that they are by no means waste products of metabolism.”