Several plants attacked by Synchytrium fulgens exhibit the resistance termed by Stakman as hypersensitiveness. In the course of the intracellular development the parasite suffers sooner or later from the necrobiosis and finally, as a manifestation of death, semipermeability of its protoplasm vanishes and causes shrinkage of its body. At this moment the host cell is still alive. The substances released from the dying parasite are considered to act upon the host cell detrimentally and to kill it immediately. Thus, it may be said that the host cell kills the parasite and in turn is killed by the dying parasite. Therefore, the death of the host cell does not participate in in ducing the resistance.