[Circulation of tissue thromboplastin in the blood]

Tissue thromboplastin injected i.v. in the form of microsomal fraction of the aorta intima was rapidly eliminated from the blood flow but did not enter into the lymph in any considerable amount. The disintegration products of the microsomal fraction of the aorta intima are released into the blood flow mostly within 5 days as revealed by the 5'-nucleotidase activity.