Abstract
In a recent investigation made by the author and a co- worker certain apparent discrepancies were noted in the results obtained. The object of the aforementioned investigations was to determine the value of secreted volatile oils to the plant. In determining the power of these oils to protect the plant against bacterial invasion, the germicidal powers of quite a number were accurately determined. Regularly used chemical germicidal agents are known to differ in their power to kill bacteria; for instance, phenol kills more readily than alcohol. Some bacteria are generally accepted to be more resistant to chemical germicides than others; typhoid bacilli are much more susceptible to germicides than the staphylococci, etc. Yet, it has been thought that a more or less definite parallel existed between the action of various germicides on different organisms. This work, however, failed to show any such definite parallel between the activities of the volatile oils. The question then became one of determining whether this discrepancy could be justified in the light of present knowledge.