1. A number of soils—treated with acid and washed free from it—have been found to possess in high degree the power of destroying phenol. Soils derived from certain geological formations seem to possess this property more than those derived from others. 2. This effect has been obtained from soils treated with sulphuric, hydrochloric, nitric, phosphoric, formic, and acetic acids. 3. The bulk of the loss of phenol is instantaneous; but the maximum loss is attained within about 20 hours. 4. An inverse relation seems to exist between the period of contact of acid with soil and the extent of the subsequent loss of phenol. 5. The loss of phenol is prevente d by several treatments—ignition of soil before or after acid-treatment; treatment with alkalis or sulphurous acid after acid-treatment; autoclaving the soil after acid-treatment and also in less degree before acid-treatment.