284 ■ EUPEORBIACE^. 



valerianic acid; also the rdlatile tiglinic acid, C^R^O^, Vihich 

 was recognized by Geuther and rrolich (1870), but bad 

 previously been observed by Scblippe (1858), wbo considered it 

 to be identical with angelicic acid. However, it melts at 64° C, 

 boils at 198-5° C, and is identical with Frankland and Duppa's 

 methylcrotoiiic acid. In the fraction boiling above the 

 temperature named, capronic, cenanthylic, or similar acids are 

 probably present. They did not succeed in obtaining from croton 

 oil an acid having the composition of Schlippe's crofonic acid, 

 Q^K^O\ E. Schmitt (1879) corroborated these statements, and 

 found among the volatile acids also formic acid. Schlippe's 

 crotonol, C'^H^^O*, has likewise not been obtained by other 

 chemists ; it was stated to be a yellowish viscid mass of a faint 

 odour, and to be the rubefacient principle of croton oil. The 

 drastic rubefacient properties, according to Buchheim (1873), 

 reside in crotonoleic acid, which is present in the free state and 

 as glyceride, and which seems to be related to ricin oleic acid, 

 since, like the latter, it yields with nitric acid oenanthic acid, 

 and on the distillation of its sodium salt gives cenanthol. 

 (Stille and Maisch.) 



H. Senier {Pharm. Journ. [3], XIV., 446, 447) has shown 

 that when alcohol (sp. gr. -794— -800) is mixed in equal 

 volumes with English pressed croton oil, perfect solution takes 

 place, the mixture being permanent at all ordinary tempera- 

 tiires, and this is equally true when any less quantity ot 

 alcohol is used; when, however, the proportion of alcohol to 

 croton oil becomes as seven volumes to six, or any larger 

 proportion of alcohol, then a part of the croton oil separates. 

 This part varies in quantity in the case of different samples of 

 oil. That part of the croton oil which separates when the 

 alcohol is in excess is afterwards insoluble in any proportion of 

 alcohol. But that portion of the oil dissolved by alcohol is, 

 when separated, soluble in aU proportions. The author has 

 shown that the part of croton oil soluble in alcohol contains the 

 vesicatmg principle, while the portion insoluble in alcohol is 

 entirely non-vesicating. He also shows that the purgative 

 properties of croton oU reside entirely in this insoluble, 



