324 



GEKMICIDAL ACTIVITY OF KUCALYPTUS OILS, 11., 



The older oil is undoubtedly the stronger germicide, and this 

 is not on account of the great amount of acid which it contained, 

 because the neutralisation of the acid did not appreciably alter 

 the efficiency. The crude oil of E. cinerea has, compared with 

 many other oils, a high saponification number, 144 to 24,* which 

 indicates a preponderance of esters. These apparently become 

 hydrolysed in course of time, producing acids and alcohols, and 

 it is either to the alcohols or to their oxidation products that the 

 increased germicidal effect is to be traced, for. as we shall see 

 later, the aldehvdes are the most bactericidal components of the 

 oils. 



k»Ct 



z 

 9 

 i- 



—i 



o 



1*00 + 



10 .>■- 



5K 



■4- 



-t- 



15 30 



60 



HO 



Text-fig. iv. 



H 



190 MINUTES 



MO 



It had been suggested that as the crude oils in most cases 

 contain substances of a phenolic nature, they would probably be 

 more germicidal than the rectified oils. When the crude oil of 



Baker and Smith, The Eucalypts and their Essential Oils, 



