A Considerable area of pasture land in Mid-Somerset, known locally as “teart” land, and also a smaller area in Warwickshire, cause scouring in cattle at certain times of the year. These pastures are a source of loss to the farmers and, from time to time, have been the subject of investigation. In 1862 the late Dr J. A. Voelcker published a valuable report on the subject, and in the main the observations and results discussed in the present paper are consistent with the suggestions which he put forward. Details of more recent work are to be found in various reports in the Journal of the Bath and West Society from 1895 to 1904.