239 CROTON TIGLIUM 



presents a black appearance. This testa is brittle, and encloses a 

 pale-coloured, delicate seed-coat, within which is the yellowish- 

 oily albumen enclosing the embryo which has been already 

 described. The seeds have no odour, and at first they have but a 

 mildly oleaginous taste, but soon become persistently acrid and 

 burning. 



The principal constituents of croton seeds are a fatty fixed oil 

 (see Characters of Croton Oil), tiglinic acid, crotonic or quartenylic 

 acid, and crotonol. The latter is asserted by Schlippe, who has 

 alone isolated it, to be the drastic principle of croton oil. The 

 purgative principle has not been isolated. Tuson has indicated 

 the presence of an alkaloid in croton seeds analogous to 

 cascarillin from cascarilla bark, but his experiments require con- 

 firmation. 



General Characters of Croton Oil. Two varieties of croton oil 

 are known in this country ; one which is imported from India, 

 and another, the one now almost generally in use, is expressed 

 here from croton seeds which are Chiefly imported from Cochin 

 or Bombay. In India, in order to obtain the oil, the seeds are 

 first subjected to slight torrefaction, by which the shell is more 

 easily separated, and the kernel or nucleus is then submitted to 

 pressure. In this country the commercial seeds, after having 

 their shells removed, are submitted to pressure. The kernels 

 yield from 50 to 60 per cent, of oil. Croton oil has a fluorescent 

 appearance, more especially the English pressed oil, a viscid 

 consistence, which is increased by age, a faint, peculiar, some- 

 what rancid, disagreeable odour, and an oily, acrid taste. The 

 colour of the two varieties varies, that of the East Indian croton 

 oil being pale yellow, and the English oil varying from 

 brownish yellow to dark reddish brown like the deepest coloured 

 sherry. Both kinds are soluble in ether and oil of turpentine, 

 but they vary in their relations to alcohol that of English oil 

 being entirely soluble, while the Indian oil forms an opaque 

 mixture with alcohol, which becomes clear if heat be applied, but 

 the oil separates again by standing. Croton oil essentially consists 

 of the fatty fixed oil mixed with the other constituents of the seeds. 



