OILS 277 



then removed from the press, mixed with hot water, and 

 pressed a third time, yielding an oil for lubricating or soap- 

 making purposes. The stearin and other material is allowed 

 to settle out, after which the oil is decanted from the top and 

 filtered to render it clear. Large quantities of olive oil are 

 used for table purposes. The United States alone imports 

 nearly 7,000,000 gallons of olive oil annually in addition to the 

 considerable quantities produced in California. Low grades 

 of the oil are used in textile soaps, in calico printing, in me- 

 dicinal soaps, and for various other purposes. 



Castor oil is derived from the familiar castor bean (Ricinus 

 communis), a plant native to Africa, but now cultivated every- 

 where in the Tropics and subtropics. The castor bean has been 

 grown for the bean as far north as Kentucky in the United 

 States and as an ornamental even in Canada. The plant is cul- 

 tivated chiefly as an annual, but in the Tropics some varieties 

 reach a height of 40 feet as a perennial. There are many 

 varieties of castor bean, differing in color and marking of the 

 seed and in habit of growth. 



The chief sources of castor bean are India, Java, Persia, 

 China, Japan, Mediterranean countries, Mexico, and the 

 United States. The yield of beans varies from 12 to 30 bushels 

 per acre. The United States imports 900,000 bushels of castor 

 beans annually, while India exports 3,000,000 bushels of beans 

 and 2,000,000 gallons of castor oil per year. 



The castor bean yields from 25 to 40 per cent, of oil by pres- 

 sure. The bean also contains a poisonous alkaloid known as 

 ricin. Ricin does not pass into the oil if pressed cold. The 

 first cold expression yields a medicinal oil of high grade. Sub- 

 sequent expressions yield low-grade oils used for lubricating 

 and manufacturing purposes. Low-grade or damaged castor 

 beans are commonly treated directly with chemical solvents for 

 the complete extraction of the oil to be used for manufactur- 

 ing purposes. 



In Oklahoma, castor beans are planted 15 to 18 inches 



