M. Strecker on Arbutine. 425 



a substance of organic origin. The stone had the usual compo- 

 sition of a meteorite, but contained in addition a certain quan- 

 tity of free carbon, and, further, a small quantity of a carbona- 

 ceous, readily fusible, and partially volatile substance, soluble in 

 alcohol. This substance had most analogy with the fossil waxes, 

 as ozokerite ; but the quantity was too small to permit of a quan- 

 titative investigation. 



Kawalier obtained in 1853, from the leaves of the Arbutus, a 

 crystalline bitter principle which he named arbutine. He 

 ascribed to it the formula C^^ H^^ 0'^ ; lie found that under the 

 influence of emulsine it was resolved into grape-sugar and an- 

 other crystallizable substance, arduvine. This substance has 

 recently been examined by Strecker*, who assigns to it another 

 formula, and shows that the arctuvine of Kawalier is identical 

 with hydrochinone obtained by Wohler from kinic acid. When 

 arbutine is boiled with dilute sulphuric acid, it is resolved into 

 grape-sugar and hydrochinone. The latter substance is obtained 

 by agitating with ether the acid aqueous solution in which it is 

 formed; on evaporation, the etherial solution deposits hydro- 

 chinone in colourless crystals which are soluble in alcohol and 

 water. Its physical properties, composition, and decompositions 

 leave no doubt as to its identity with the substance discovered 

 by Wohler. 



Strecker expresses the formula of arbutine by C^ H'^ 0'^ ; its 

 resolution into hydrochinone and grape-sugar takes place in 

 accordance with the equation 



C24Hi6oi4 4.3HO = C»2H6 0'* + C'2H'2 0i2. 

 Arbutine. Hydrochinone. Glucose. 



Arbutine thus corresponds to salicine, which under similar 

 circumstances experiences an analogous change. 



C26- H18 0"» + 2H0 = Ci'* H« 04+ C'2 H'^O'^. 



Salicine. Saligenine. Glucose. 



Since salicine and arbutine, as well as saligenine and hydro- 

 chinone, only diflPer by C^ H"^, it may be asked whether they are 

 not homologous. A great similarity is evident in the two series. 



At the same time the analogy between these two groups is 

 not quite so complete as might be expected from true homo- 

 logues. Thus chinone and hydride of salicyle are very different 



* Licbig's Annalen, August 1858. 



