The investigations described in this paper are in part a continuation of those described by Carroll and McMahon in a previous paper published in 1935. The previous paper demonstrated the fact that the root excretion of potatoes growing in recently sterilized soil does not possess the power of inducing the hatching of eelworm eggs in the normal manner. It was shown that when eelworm cysts were placed in soil leaching (containing potato root excretion) obtained from pots of very recently sterilized soil growing potatoes practically no hatch of the eggs in these cysts took place until after the lapse of about thirty days. It was further indicated that this interval of time which elapses before hatching commences diminishes according as the period between time of sterilization of the soil and time of obtaining soil leaching for hatching experiment increases.