N. O. ECPHORBIAOE/E. 
1171 
Uses : — Officinal in both the Pharmacopoeias, and its uses are 
too well known to be mentioned here. 
“ Leather has examined a largo number of seeds from Madras, Bombay, 
United Provinces and Central Provinces, and shows that they contain from 25 
to 36 per cent, of shells, and the kernels, with few exceptions, afford from 60 
to 70 per cent, of oil, or 35 to 50 per eent. on the entire seed. Larger seeds 
as a rule contain more oil than smaller seeds. 
Castor oil is a colourless or pale greenish oil having a taste at first mild, 
then harsh. The oil is very viscous, but does not dry even when exposed in 
thin layers. Most commercial samples contain only very small proportions 
of free fatty acids, this is due to the refining process which consists in the 
coagulation of albuminous matters by steaming and then removing them by 
filtration. Castor oil is strongly dextro-rotatory. Deering and Redwood 
examined twenty-three samples of Indian oil and observed that in a 200 mm. 
tube in a Hoffmann-Lanrent polarimeter the variation was from-t-7'6 0 to 
+9 , 7’. Castor oil may be said to consist of a small quantity of tristearin, 
of the glyceride of dihydoxysteario acid, and to a large extent of the glyce- 
ride of ricinoleic acid. 
The physical and chemical constants of the oil have been found as follows : 
Specific gravity at 15'5°, 0-968 to 0'964 ; saponification value, 177 to *184 ; 
iodine value, 81'4 to 85'3 ; Richert-Meissl value, 1-1 ; Maumene test, 46-4? ; 
oleo refractometer "degrees at 22°, 41 to 42'5. Insoluble fatty acids: Melting 
point, 13° ; iodine value, 86 to 88. 
The high specific gravity and acetyl value and its very high viscosity 
afford ready means of identification. It is also miscible in all proportions 
with glacial acetic acid and absolute alcohol, but is nearly insoluble in large 
quantities of petroleum ether, kerosene and higher boiling paraffn oils." 
(Agricultural Ledger, 1911-12 No. 5 pp. 164-165.) 
Ricinin, C 17 H 13 N 4 0 4 is the poisonous principle of the seeds. The pressed 
seeds yield 0‘3 per cent., whereas the husks yield 1*5 per cent., of ricinin. 
To obtain the ricinin, the pressed seeds or husks are extracted with boiling 
water; the extract evaporated on the water bath, and the residue treated 
with alcohol. The alcoholic solution is then evaporated , to dryness and the 
residue treated with caustic soda; Gy this means, the impurities are dissolved 
out, and the ricinin which remains behind may be crystallised from alcohol 
or water. It crystallises in glistening plates ; melts at 194°, has a bitter taste, 
is readily soluble in water, alcohol, chloroform, benzene and ether; the 
aqueous solution is neutral and optically inactive. Ricinin may be sublimed 
when carefully heated ; it is soluble in concentrated sulphuric acid, yielding 
a colourless solution, which becomes straw-yellow, and then bright claret red, 
on warming. The colourless sulphuric acid solution gives, with a crystal of 
potassium dichromate, a bright green coloration ; this is suggested as a test 
for ricinin. Ricinin does not give the usual tests for alkaloids, neither does 
it form salts with strong mineral acids ; it yields a bromo-derivative, C 17 H ln - 
Br, N 4 0 4 , which melts at 247°, and a corresponding chloro-derivative, which 
melts at 240.° With mercuric chloride, it yields the compound, C 17 H 13 N 4 0 4 , 
2HgCl 7 , which melts at 204°. When oxidised, it yields a new acid, C lS H l4 
