The author, employing certain rabbits, and after having induced in them a bone fracture experimentally, examined for 9 weeks since that date, such facts as changes that have occurred to serum protein, function of reticulo-endotherial system, number of leucocytes, erythrocytes, Hb, Ht, or B.S.G.: and further, by examining the effects that have ensued the administration of Platonin, finally has obtained results as follows: Those changes that have occurred to the number of leucocytes, erythrocytes, Hb, Ht, or B.S.G., have proved at a glance to be slight, yet showed strong in preaction in proportion to the seriousness of the disease, which, however, recovered by the administration of Platonin. The function of the reticulo-endotherial system has proved to lower at the beginning of injury, but soon revived, even where, the lowering degree has been slighter and sooner recovered in slighter affections, rather than in more serious cases. Moreover, even this thenomenon has been mitigated by the administration of Platonin. As to serum protein, due to the changes in each fraction, certain significance has been attached to A/G value; in changes of which too, the decrease at the beginning of injury showed to be slight in slighter diseases; and besides, proved to recover sooner. Moreover, this tendency has been strengthened by Platonin.