The investigators who employed frequently repeated intravenous injections of adrenalin into rabbits for the production of aortic lesions commonly noted at the autopsy not only blood-vessel but also myocarditic changes. So far it has not been possible to study the succeeding stages in the development nor the ultimate outcome of this disease.
A short time ago we found that one single injection of adrenalin (0.2 c.c.) cause in many cases a myocarditic lesion and that one injection of a combination of a relatively small dose of adrenalin and spartein or caffein produced macroscopic changes in the heart of the rabbit in about 60 per cent. of the cases and microscopic changes in almost all of the animals. We concluded therefrom that a cardiac and not an aortic lesion was the typical effect of intravenous injection of adrenalin. This enabled us to establish the sequence