There are many studies on radiation disturbances but as for the causative factor of the disturbances it is vaguely considered to be the disorders of the hematopoietic organs and still it is uncertain whether such disturbances are due to the primary or the secondary factor, However, in our experiments we have come across the evidence indicating that such disorders can be induced even by an indirect causative factor. Following upon this point, we have studied the problem from histochemical standpoint of blood cells and have clarified that various substances what may be called toxic granules are produced during X-ray irradiation. Therefore, with the purpose to find an aid in the diagnosis of radiation disturbances as well as a clue in the eluc...