The Interaction between Blood Serum and Tis- Sue Extract in the Coagulation of the Blood. I. the Combined Action of Serum and Tissue Extract on Fluoride, Hirudin, and Peptone Plasma; the Effect of Heating on the Serum. by Leo Loeb,

On former occasions we have discussed repeatedly the action of tissue extract and serum separately, as well as their combined action on fluoride, hirudin, and peptone plasma of vertebrate blood,l We pointed out the loss in power of a mixture of serum and tissue extract on standing and the difference in the behavior of fluoride plasma (and similar plasmas) in which coagulation had been prevented through inactivation of calcium on the one hand, and of hirudin and peptone plasma on the other hand. We also determined how far the specific adaptation of the tissue coagulins depended upon a combination with a constituent of the blood serum and on the direct action of these substances on the coagulable plasma. In this and the following paper we shall report on a continuation of these experiments and especially shall we analyze the changes which take place in a mixture of tissue extract and blood serum on standing.2 A discussion of our con-