2 BULLETIN 867, U. S. DEPARTMENT OF AGRICULTURE. 
brown to black. The beans vary in weight from 0.10 gm. to 1.22 gm., 
and in size from 7.5 mm. long by 50 mm. wide by 4.5 mm. thick to 
23mm. by 15mm. by 8mm., respectively. One cubicfoot of beans of 
average size weighs about 37 pounds. 
An analysis of a commercial sample of castor beans shows ‘that 
the whole bean consists of 35 per cent of seed coat and 65 per cent of 
kernel, the oil content of these two parts being 10 and 62.9 per cent, 
respectively. 
Analyses of 37 samples of castor beans imported from India, China, 
the West Indies, and South America show a range of oil content, 
determined by ether extraction, from 38.39 to 55.55 per cent, with 
an average value of 48.75 per cent. Similar assay of 50 samples of 
beans from the first American crop from imported seed in i918 
shows a range of 42.13 to 58.57 per cent, averaging 48.16 per cent. 
With present milling practices there is obtained about 15.6 pounds 
of No. 1 oil per 46-pound bushel, 4.1 pounds of No. 3 oil, and 25.5 
pounds of pomace, with a shrinkage per bushel of about 0.8 pound. 
Castor beans contain a poisonous principle which renders them 
extremely dangerous when eaten. Also picking off the seed coats 
with the fingers has been followed by inflammation and soreness under 
the finger nails. Persons who have weak eyes or who are subject 
to hay fever may suffer serious inconvenience, to say the least, fol- 
lowing exposure to the dust from ground dried castor pomace 
The common belief that the coloring matter occurring in castor oil 
extracted by the solvent process is introduced through the so-called 
germ has not been borne out by experiments. On the contrary, the 
color seems to be mostly derived from the seed coats. It is observed 
that decorticated kernels yield a light-colored oil when extracted 
by volatile solvents, while the whole bean or the seed coats alone 
yield progressively more highly colored oils. But the coloring matter 
is evidently not a single simple substance, for upon extraction with 
different solvents different colors are obtained. Benzol gives a green- 
colored oil, gasoline a yellowish oil, while methyl ethyl ketone, ace- 
tone, ethyl alcohol, and methyl! acetate all yield a red-colored oil 
which slowly turns to dark brown on exposure to the air. 
Castor beans also contain the enzym lipase, which is extremely 
active in hydrolyzing the oil to glycerin and free fatty acid. This 
action does not occur so long as the seed coat remains intact and 
protects the kernel from exposure to the air, but when the seed coat 
is broken the enzym quickly begins its hydrolytic action. Since 
broken and damaged beans when crushed yield a highly colored 
acid oil, care must be exercised in hulling and Sate to avoid 
breaking the seed coats. 
Another factor contributing to the high acidity of castor oil is what 
are known as black beans. These are rancid beans, the kernels of 
