M. H. Bleibtreu on Cumarine. 485 



most lively manner attracted by the investigations of Cahours 

 on the " Oil of the Gualtheria procumbens." 



Delalande expresses these transformations by the following 

 formula : — 



C 18 H 7 4 + 2HO = HO,C 18 H 7 6 + H 



' , ' • , ' 



Cumarine. Cumaric acid. 



HO, C I8 H 7 3 = HO, C 14 H 5 O s + C 4 H,. 



v • , , ; , 



Cumaric acid. Salicylic acid. 



On repeating the experiments of Delalande I arrived at 

 the following results. 



Cumarine dissolves readily in potassa and forms with it a 

 yellowish solution, from which acids precipitate cumarine 

 again unchanged. It is only attacked by heating with con- 

 centrated ley, to which pieces of solid caustic potassa have 

 been added. From this solution hydrochloric acid precipi- 

 tates a substance totally differing in its character from cuma- 

 rine, and which is evidently the acid described by Delalande. 



By careful treatment of cumarine however by potassa, I 

 have never been able to observe a disengagement of hydrogen. 



The acid prepared in the above manner may contain traces 

 of salicylic acid. After removal of the chloride of potassium 

 and the excess of hydrochloric acid, and dissolving in water, 

 it gave indeed, with salts of the sesquioxide of iron, the violet 

 colour so characteristic of salicylic acid. Delalande however 

 states expressly in his memoir, that this reaction is not only 

 characteristic of salicylic but also of cumaric acid. This re- 

 mark is evidently erroneous, for on washing with water the 

 acid once crystallized, this reaction became weaker and weaker, 

 and finally totally disappeared on a second crystallization. 

 The violet colour produced by the sesquichloride of iron 

 was consequently due to the presence of a small quantity of 

 salicylic acid, the formation of which cannot easily be pre- 

 vented. 



The acid prepared in the above manner, and freed from 

 salicylic acid as much as possible by repeated recrystalliza- 

 tions, may still contain traces of undecomposed cumarine, 

 from which it must be separated ; for this purpose it was 

 dissolved in ammonia. From the yellow solution the excess 

 of ammonia was expelled by boiling, and the yellowish-white 

 silver salt produced by the addition of nitrate of silver was 

 collected on a filter and washed with water, and then with 

 alcohol, and finally aether. After such a treatment the silver 

 salt cannot contain any trace of cumarine, and the acid now 

 separated by hydrochloric acid, extracted by aether, and re- 



