] 92 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



used and the costs involved in their pio{hicti()n. To meet the in- 

 creased demand for detailed information a field study of several 

 essential oil crops was uuilertaken. The data collected show in the 

 case of wormwood oil, for example, that in most cases the principal 

 limitin<ji: factor of production is the net return obtainable from other 

 comjietinfr farm crops. 



In the laboratory a study is in progress on the distribution of the 

 essential oil in the plant and on the metabolic processes underlying 

 the production of the various constituents which give these oils their 

 value. 



OIL-SEED CROPS. 



Through informal cooperation with individuals in widely sepa- 

 rated localities field tests of several new oil-seed crops have been 

 made. Five varieties of oil-seed hemp were tested at field stations 

 and a quantity of seed secured for further tests on a field scale. 



Important data on the technology of vegetable-oil production have 

 been secured through laboratory and field w^ork. A study of the 

 production and refining of corn oil has yielded data on the cost of 

 producing this oil and the relative profits arising from using corn 

 germs for stock feed or as a source of oil. 



A study is being made of the oil from selected strains of standard 

 varieties of peanuts to determine their suitability for oil production 

 when grown on various types of soil and under different climatic 

 conditions. 



In the castor-oil mill operated for the War Department at Gaines- 

 ville, Fla., an exhaustive study w^as made of the expeller and solvent 

 extraction process of obtaining a high recovery of oil from castor 

 beans. The data secured on solvent extraction are especially timely., 

 since there is at present a growing interest in this process of oil 

 technology. 



It has been determined that the mold which attacks corn under 

 certain conditions of storage not only causes a reduction in the yield 

 of oil, as compared with the yield of oil normally obtained from 

 sound corn, but also causes a decided increase in the free acids and 

 unsaponifiable constituents of the oil. The source of the discolora- 

 tion and objectionable odors wdiich sometimes develop in white soaps 

 and certain other technical products has been traced to the oil from 

 moldy corn used in their manufacture. 



UTILIZATION OF AGRICULTURAL WASTE PRODUCTS. 



The investigation of the waste materials of corn canneries has 

 shown that corn cobs and husks, when properly dried and ground, 

 can be used very satisfactorily as a stock feed. 



Valuable fixed oils have been extracted from the various oil-bear- 

 ing weed seeds which form the bulk of grain screenings. Although 

 not all weed seeds separated from grain have a large oil content, 

 several have been found which contain high percentages of oil. In 

 case of need a substantial quantity of useful oil could be produced 

 from the large tonnage of grain screenings annually available in this 

 country. 



