Grouping diacharges of both parkinsonian tremor and clonus of the calf muscles were suspended a certain period with a same patient (160 to 180msec.) in tremor and 100 to 110msec. in clonus followed by the same grouping discharges as before the shock when a shock was given to the nerve to provoke the monosynaptic H-reflex response on the calf muscles. It should be noted that this is not anommission of the grouping discharge but a suspension of a certain period. This difference of the period observed in tremor and clonus does not seem to depended on difference of mechanism driving the tremor and the clonus as the period of suspension showed pararell relation to frequency of the motor unit discharge when measured during voluntary contraction with various in tensities in normal subject. The following clinical data of the chemopallidectomy may support this opinion that localized lesion of the pallidum is not always effective to the tremor although it is effective to the rigidity unless otherwise the pyramidal tract is involved somewhat.