346 ODOROGRAPHIA. 



An oil is also obtained by aqueous distillation from the young 

 leaves of Betida alba. 



The aromatic product derived from the bark of the " White 

 Birch," Betula alba, is an empyreumatic oil or a decomposition 

 product obtained by the partial combustion or slow destructive 

 distillation of an organic constituent of its bark, the odour being 

 usually known as " Kussia Leather." It is described in the 

 chapter on " empyreumatic oils." 



