T5Y R. GREIG-SMITH. 73 



referred to ;is the oil of Eucalyptus globulus. This oil was 

 originally sent to Europe, and is still distilled in Tasmania; but 

 there is reason to believe that many oils of mixed and doubtful 

 origin were exported in the past under the name of E. globulus. 

 At the present time, much of the oil can be trusted to be true to 

 species-name. E. globulus is also found in the South-Eastern 

 States of the Commonwealth, hut the trees are usually too 

 neutered to be profitably collected, while the yield is poor; and 

 as other species give higher yields of good quality, these furnish 

 the oils to the trade. 



In New South Wales, the chief sources of oil at present are 

 E. polybractea (the "Blue Mallee" of the Wyalong district), E. 

 cinerea (the "Argyle Apple"), E. australiana (the "Narrow-leaf 

 Peppermint"), and E. dives (the "Broad-leaf Peppermint"). The 

 three first species yield cineol (eucalyptol) oils for pharmaceutical 

 purposes The oil of E. dives has the terpene, phellandrene, as 

 the chief constituent, and is mainly used for the flotation of 

 minerals. 



The action of the oils when used in ointments was given first 

 consideration, and, as these are generally used for skin-ailments 

 caused by the white and yellow staphylococci, it was thought 

 that much useful information would be gained by testing dilu- 

 tions of the Eucalyptus oil in an inert oil, such as olive oil, 

 against the yellow staphylococcus suspended in serum. An 

 exposure of two hours was deemed sufficient. 



The test-organism was grown on nutrient agar overnight at 

 37°, and, in the morning, a loop was smeared over the surface of 

 an agar-slope, which was incubated at 37° for three hours, during 

 which the dilutions were prepared. Blood-serum was obtained 

 in the manner used in opsonic work, and a loop of the agar- 

 growtb was thoroughly mixed with some of the serum. In pre- 

 liminary experiments, the infected serum was smeared within 

 the lower ends of glass-tubes, but, as it subsequently fell away 

 in flakes, the method was altered, and a loop of the serum was 

 absorbed in strands of cotton attached to wire-loops. These 

 loops were made by bending a seven-inch length of wire, B.W.G. 

 No. 21, round a thick wire, and thickly coating the loop and the 



