Field observations made in 1935 on a potato crop growing on what was thought to be potato sick land in Bedfordshire seemed to indicate that eelworm damage due to Heterodera schachtii was less pronounced where maize had been the previous crop than in other cases. As particulars of the history of this piece of ground were not available, detailed observations were not made, but it was decided that it might be valuable to carry out experiments with maize to determine whether this plant had any effect on eelworm cysts. Other members of the natural order Gramineae have been shown by Triffitt to stimulate the larvae of H. schachtii to hatch from the cysts, and it was thought that maize might have a similar effect.