[Role of the liver in producing heat-stable antifactor Xa]

The thermostable antifactor Xa is demonstrable in liver homogenate extracts in an amount exceeding its content in other parenchymatous organs and blood serum. In the course of liver perfusion and incubation of liver sections, the antifactor is demonstrable in the perfused liquid and in the medium used for incubation. Affection of the liver with carbon tetrachloride was attended by the decreased content of the antifactor in serum. The liver seems likely to play an important role in the production of the thermostable antifactor Xa.