Up to the present time investigators have been able to isolate by filtration only toxins which go into solution in our liquid culture media. The best known examples of this are the diphtheria and the tetanus toxins. It has been to a degree disappointing that similar toxins could not be obtained from the typhoid, cholera and other organisms, as the possession of such toxins might make possible the preparation of antisera, to be used in the treatment of the diseases in question.
Recent work by Conradi, also by Neisser and Shiga, seems to indicate that some advance has been made in this direction. Conradi had previously observed that when certain organs (e. g., liver) undergo aseptic autolysis or self-digestion, through the agency of preformed intracellular ferments, substances were produced which hindered or prevented the clotting of blood in vitro. The same occurred in autolysis of yeast cells; and, furthermore, in