Calcium content in the serum, bone, muscle, brain tissue and urine of the ep-mouse were measured. The results were as follows; 1) Urinary calcium excretion of the ep-mouse was higher than that of normal mouse. 2) As to the quantitative change of urinary calcium excretion of the ep-mouse in the days following birth, it was observed that the urinary calcium excretion was highest in the early stage of immaturity, thereafter gradually decreased in the late stage, then moderately increased again in the mature stage. 3) As to the quantitative change of urinary calcium excretion during convulsions, it was observed that the urinary calcium excretion decreased in one hour following the convulsion, then gradually increased, attaining the normal range within five hours. 4) No significant difference was found in the calcium content of serum, bone and brain of ep-mouse in comparison to normals, but decreased calcium content was observed in the muscle of ep-mouse. 5) Calcium content in the brain of ep-mouse increased a little during the convulsive stage as compared to that of nonconvulsive stage, but, after convulsion, it gradually reached the normal range.