In collaboration with Mr. Selman of King's College, London, I have also investigated the influence of supersonic treatment on sweet corn. Inspection of results indicates that supersonic treatment does have an effect in that weaker seedlings are killed off. Thus the averages of treated material, compared with the controls, for such characters as growth, height, and tiller number, is slightly higher. But on allowing for this, it is found that supersonic treatment of various intensities has little, if any, influence. This disagrees with the results of Wallace but is in agreement with Hersh.