BUCHU. 231 



Diosphenol usually forms acicular crystals ; by slow crystallis- 

 ation somewhat larger, well defined crystals were obtained which 

 were crystallographically examined in Professor Groth's laboratory 

 by Dr. A. Cathrein, and found to belong to the monosymmetrical 

 (monoclinic) system. (A diagram of the form of crystal and 

 measurements of the angles of the faces are given in Pharm. 

 Journ. [3], xi. p. 219). 



The crystals of diosphenol melt at 83^ C, and boil at 233^ C, 

 but cannot be distilled by the usual method without suffering 

 partial decomposition. The solidifying point after fusion is 50^ C. 

 By subliming diosphenol in the temperature of a steam-bath, thin 

 prisms, two inches long, are easily to be obtained. It is readily 

 soluble in alcohol of sp. gr. 0-83, less so in ether, but very sparingly 

 in water. The aqueous solution in boiling water on cooling affords 

 small acicular crystals. The solutions are perfectly neutral, and 

 on addition of an alcoholic solution of ferric chloride assume a 

 dark coloration of dingy green. The crude oil, as well as the 

 water distilled from buchu leaves, exhibits the same behaviour. 



Diosphenol has a slightly aromatic odour and taste, " sui generis," 

 by no means reminding of buchu leaves, but rather of mint. It is 

 soluble in concentrated sulphuric acid, but without forming a 

 crystallisable compound ; on saturating the brown solution thus 

 obtained with carbonate of baryum and duly concentrating the 

 filtrate, only a small quantity of uncrystallisable barium salt is 

 obtainable. 



Diosphenol is also readily dissolved by caustic lye, but it is not 

 decomposed by the carbonates ; by carbonic acid on the other 

 hand, it is precipitated from its solution in potash, soda, or 

 hydroxide of barium. In 50 parts of the latter (Ba (0H)„ -f- 8 

 OH 2 in twenty parts of water) diosphenol dissolves very slowly. 

 By allowing such a solution to evaporate slowly over lumps of 

 potash, no well-defined bari%m compound of diosphenol could be 

 obtained, crystals of the pure phenol even gradually making their 

 appearance on the sides of the beaker. ISTeither could solid 

 potassium or sodium compounds be prepared. (In the opinion of 

 Professor Flitckiger these experiments show that the substance 



Oct., 1886, and Phavm. Journ. [3], xvii., p. 547), who calls this substance an 

 '* oxycamphor " of the composition C^o ^le O2J b^^ 1^^ ^^'^^ evidently made a 

 mistake in his figures. 



