NITROGEN-GCONSUMIN PLANTS 237 



Castor Oil ((Ricinus communis). The medicinal castor oil obtained 

 from the seeds of this plant has strong laxative properties. There was a 

 great demand during the late world war for castor oil as a lubricant for 

 aeroplanes. 



Quinoa (Chenopodium quinoa). The small, round, white seeds of this 

 South American plant are used as a food. 



Betel (Areca catechu}. The seeds of this palm are gathered in India 

 and elsewhere for use as a masticatory, or chewing material. The seeds 

 are sliced and rolled up with lime in leaves of the betel pepper. The 

 teeth of the consumer are stained with the juice. 



Modern experiments prove that the production of the nitrogen-con- 

 suming plants (root crops, bulb crops, stem crops, leaf crops, flower crops, 

 fruit crops, seed crops, cereal crops, as above) should be alternated with 

 the cultivation of the nitrogen-storing plants, such as alfalfa, clover, beans, 

 cowpeas, soy-beans, lupines, which accumulate atmospheric nitrogen by 

 the agency of the bacteria in their root nodules. With a view to emphasiz- 

 ing this fact as we have proceeded with our descriptions approved rota- 

 tions have been given for various crop plants in which rotations the 

 leguminous plants have prominently figured. Progressive farmers should 

 grow-nitrogen accumulating plants for home consumption and nitrogen- 

 consuming crops for sale and removal from the farms where produced, 

 either to home, or to foreign markets. This system should be extended so 

 as to comprehend the whole country in a complete and perfect system of 

 rotation. It will bring about a diversification of agricultural industries, 

 so as to permit the cultivation of the crops best adapted to the climate and 

 soil zones of America and other countries. 



BIBLIOGRAPHY 



ALLEN, E. W.: Leguminous Plants for Green Manuring and for Feeding. Farmers' 



Bulletin 16, U. S. Department of Agriculture, 1894. 

 CAMERON, S. C. R.: The Wild Foods of Great Britain where to Find Them and how 



to Cook Them. London, George Routledge & Sons, Ltd., 1917. 

 COLLINS, S. H.: Plant Products and Chemical Fertilizers. New York, W. Van 



Nostrand Company, 1919. 

 DODGE, CHARLES RICHARDS: Flax for Seed and Fiber in the United States. Farmers' 



Bulletin 27, 1895. 



DUGGAR, J. F.: Sweet Potatoes: Culture and Uses. Farmers' Bulletin 26, 1895. 

 DREWS, GEORGE J.: Unfired Foods and Trophotherapy. Chicago, 1919. 

 FISCHER, ALFRED: The Structure and Functions of Bacteria. Oxford at the Qarendon 



Press, 1900, 88-106. 



