566 EUPHORBIACE^. 



which the kernels afford from 50 to 60 per cent. That used in England 

 is for the most part expressed in London, and justly regarded as more 

 reliable than that imported from India, with which the market was 

 formerly supplied. It is a transparent, sherry-coloured, viscid liquid, 

 slightly fluorescent, and having a slight rancid smell and an oily, acrid' 

 taste. Its solubility in alcohol (-794) appears to depend in great measure 

 on the age of the oil, and the greater or less freshness of the seeds from 

 which it was expressed, — oxidized or resinified oil dissolving the most 

 readily.' We found the oil which one of us had extracted by means of 

 bisulphide of carbon to be Icvogyre. 



Croton oil consists chiefly of the glycerinic ethers of the commou 

 fatty acids, such as stearic, palmitic, myristic and lauric acids. They 

 partly separate in the cold ; the acids also may partly be obtained by 

 passing^ nitrous acid through croton oil. There are also present in the 

 latter, in the form of glycerinic ethers, the more volatile acids, as 

 formic, acetic,_isobutyric and one of the valerianic acids.^ The volatile 

 part of the acids yielded by croton oil contains moreover an acid Avhich 

 was regarded by Schlippe (1858) as angelic acid, C^H^Q-l Yet in 1869 

 it was shown by Geuther and Frolich to be a peculiar acid, which 

 they called Tlglinic add. Its composition answers to the same formula, 

 C*H^COOH, as that of angelic acid; but the melting points (angelic 

 acid 45°, tigliriic ()4'' C.) and boiling points (angelic acid 185°, tiglinic 

 198°-5) are different. Both these acids have been mentioned in our 

 article on Flores Anthemidis, at page .386. Tiglinic acid may also be 

 obtained artificially ; it is the methylcrotonic acid of Eraukland and 

 Duppa (1865). 



SchHppe also stated croton oil to afford a peculiar liquid acid 

 termed Crotonic Acid, C/H.''0\ According to Geuther and Frolich, 

 however, an acid of this formula does nofc^occur at all in croton oil 

 By synthetic methods three different acids of tliat composition arc 

 obtainable. 



The drastic 2>rinciple of croton oil has not yet been isolated. 



Buchheim^ suggested that the action of tlic oil depends upon 



Crotonoleic acid," which however he failed in isolating satisfactorily. 



It IS remarkable that the wood and leaxcs of Croton Tiglkm&pV^^^^^ 



partake also of the drastic properties of tlie seeds. » 



bchlij)pe asserts that he has separated tlie vesicating matter ot 

 croton oil: if the oil be agitated with alcoholic soda, and afterNravds 

 with water, the supernatant liquor will be found free from acridity, 

 while the alcoholic solution will yiel.l, on addition of hydrochloric acid, 

 a small quantity of a dark brown oil, called Crotonol, possessing 

 vesicating properties. We have not succeeded in obtaining it, nor, so 



as we know, has any other chemist except its discoverer. 



Ihe shells of the seeds (testa) yield uiion incineration 26 per cent. 

 ot ash ; the kernels dried at 100" C. 30 per cent. 



Commerce— The shipments of croton seeds arrive chiefly fio'" 

 <-ochm or Bombay, packed in cases, bales or robbins; but there are uo 

 statistics to show the extent of the trade. 



38^-1?™^'*''' ^''"'■"'- •^°«''"- ^'- (1865) » In ihe Jahreshericht of Wiggers and 



^ Schmidt and Berendes, 1878. Husemann. 1873. 560. 



