140 H. G. SMITH. 



a little alcohol. The combination did not readily take place. 

 After some days a crystalline compound formed which continued 

 to increase. On adding water the crystals dissolved, the unacted 

 upon oil separating. The aqueous portion was removed and 

 decomposed with caustic soda solution. An oil at once separated 

 in good quantity showing that a compound had been formed. The 

 separated oil was well washed and then steam distilled. As thus 

 obtained it is almost colourless, and has an intense peppermint 

 taste and peppermint odour ; it is soluble in alcohol, ether, and 

 ordinary solvents, and is slightly soluble in water. 



Optical rotation. 

 The rotation in a 100 mm. tube was — 0'35°. It is probable 

 that the constituent itself is inactive, and that the slight rotation 

 was caused by the presence of a minute quantity of the aromatic 

 aldehyde present in these oils, previously supposed to be cumin- 

 aldehyde ; this itself is laevorotatory and would be extracted with 

 sodium bisulphite together with the peppermint constituent, and 

 be present in the final product. That a small quantity of an 

 aldehyde is present is indicated by the slight pink colour obtained 

 when tested by Schiff's reaction, but the quantity present can be 

 but small as this aldehyde answers to Schiff's reaction readily, 

 besides easily forming a crystalline oxime. It has not been 

 possible so far to form a crystalline oxime with the peppermint 

 constituent, it remaining persistently as a thick oil; when dissolved 

 in alcohol it had no rotation. 



The presence of a small quantity of this aldehyde in the oil of 

 E. dives again illustrates the persistency with which minute 

 quantities of the several constituents maintain their presence in 

 these oils. 



Specific gravity. 



The specific gravity of the purified material was -9393 atxi^c." 



Boiling point. 

 The purified material boils at 224 - 225° C. 



