Our early findings that the cardiostimulant effect of camphor appears inconstantly and only after a latent period during which the drug remains in contact with the tissues; while the depressant effect is seen constantly and forthwith, led us to suggest that (1) the camphor as such is to be regarded as, not a stimulating, but a paralysing agent upon the heart; and (2) the heart seems to be stimulated rather by some of its transformation products in the animal body. This really formed the starting-point of our investigation of the correlation between the fate and the action in order, if possible, to isolate the true active principle from the intermediate products. Just then, we had started to reinvestigate Schmiedeberg's achievement on the fate of camphor in the animal body, and had succeeded to separate the Schmiedeberg's campherol into its constituents, i.e., p-, o- and π-hydroxycamphors; but all our attempts to find the true cardiostimulant substance among the intermediate products of camphor before it is finally excreted as detoxicated glycuronic acid derivatives failed. Therefore, we changed the course of our inquiry into possible oxidation products of camphor in the body and, by this time of last year, we were led very close to the find object with our π-oxocamphor, as was reported previously.