What does the word serum mean?

Usage examples for serum

  1. By that time he could be practically certain whether or not the serum had " gripped" the disease, and would at last conquer it. – The Brightener by C. N. Williamson A. M. Williamson
  2. Uhlenhuth, Nuttall, and others have established the fact that the blood- serum of a rabbit which has previously had human blood injected into it, forms a precipitate with human blood. – Darwin and Modern Science by A.C. Seward and Others