CASTORIN. 149 



Castor has a yellow colour, and when newly taken from the 

 animal it is nearly fluid, but, by exposure to the atmosphere, it 

 gradually hardens, becomes darker coloured, and assumes a resi- 

 nous appearance. Its taste is bitter and acrid, and its smell strong 

 and aromatic. In water it softens and tinges the liquid of a pale 

 yellow colour. The solution contains an alkali. 



Castor was examined by Bouillon La Grange,* by Bizio,f and 

 by Brandes,! and by various other chemists. Bizio first distin- 

 guished a substance which he extracted from it by the name of 

 castorin. It had been already noticed by Fourcroy, Barneveld, 

 and Bohn ; but considered by them as adipocirc. It may be ex- 

 tracted from castor by the following process : 



Boil castor in six times its weight of alcohol of the specific gra- 

 vity 0-85 ; filter and leave the liquid in an open glass till it is 

 reduced to one-half by evaporation ; draw off the liquid portion 

 from the castorin deposited, and wash this last with cold alcohol, 

 which partly removes the brown-coloured resinous matter. To 

 remove this matter completely, digest the castorin with an aque- 

 ous solution of ammonia, potash, or soda ; or treat its alcoholic 

 solution with animal charcoal. Such is the process employed by 

 Bizio. 



Brande's process is somewhat different. He boiled castor with 

 alcohol, and filtered it hot. On cooling, it deposited a little fatty 

 matter. The alcoholic solution was then put into a retort, and 

 the greatest part of the alcohol distilled off. The liquid portion 

 in the retort was now separated from the castorin deposited. 

 This last substance was purified by washing it in cold alcohol. 



Castorin is white, and crystallizes from its solutions in fine four- 

 sided transparent needles collected together in groups. It has 

 a slight smell of castor, and a peculiar metallic taste. It does 

 not alter vegetable colours. It is light and easily reduced to 

 powder. When put into boiling water, it melts into an oil, which 

 swims on the surface of the liquid, and which, after becoming so- 

 lid on cooling, remains transparent. When boiled with water 

 in a retort, it goes over in small quantities with the liquid, which 

 is at first limpid ; but after a certain time, deposites castorin. 

 When heated per se in a retort, it melts, boils, and an orange- 



* Jour, de Phys. xlii. f Brugn. Giorn. xvii. 174- 



Br. Arch. xvi. 281. 



