The control of infection by penicillin is generally acknowledged to be dependent on the susceptibility of the bacterial species, the relative resistance of the strain responsible for the infection and the duration of its exposure to a therapeutically effective concentration.1 To these three factors we would add a fourth, the attainment of a concentration in the blood sufficiently high to secure penetration into dense inflammatory foci in which bacteria are embedded. Very much higher blood levels are necessary to obtain this objective than for simple sterilization of the blood stream.
In order to facilitate the penetration of chemotherapeutic agents into the vegetations of subacute bacterial endocarditis, some clinicians2 have heparinized their patients. It is doubtful whether the prolongation of the coagulation time of the blood to thirty or sixty minutes has any appreciable effect on the masses of blood platelets and fibrin of which the vegetations of subacute bacterial
GERBER IE, SHWARTZMAN G, BAEHR G. PENETRATION OF PENICILLIN INTO FOCI OF INFECTION. JAMA. 1946;130(12):761-764. doi:10.1001/jama.1946.02870120007002