320 



GERMICIDAL ACTIVITY OF EUCALYPTUS OILS, 11 , 



minute to the eight minute interval explains much of the great 

 irregularity in the tests. Concordant results can scarcely be 

 expected during an interval of rapidly altering activity. The 

 same gross irregularity was not noted with the weaker dilutions 

 of Table ii., or with phenol which furnishes a true solution in 

 dilutions over 1 : 5. 



t- 



120 



45 tO '20 180 MINUTES m 



Text-fig. iii. — The Cineol and Phenol Curves. 



By combining the results of Tables ii. and iii., we are able to 

 obtain the complete curves of cineol and phenol. Both are of 

 the same nature, inasmuch as they show a sharp rise followed by 

 a slowing down to a straight line rising slightly from the hori- 

 zontal. Indeed, if we were to enlarge the phenol area, we would 

 find that it had much the same shape as the cineol area. The 

 phenol curve reaches the approximately horizontal level in 1| 

 minutes, while cineol takes half-an-hour. Although more power- 

 ful as a disinfectant than phenol, it is slower in its action and 

 overtakes the quickly acting phenol at the five-minute interval 

 when each has a dilution of 1 ; 75. 



