The prevention of cell division by anti-clotting agents

Summary We have continued to interpret cell division in terms of the colloidal theory. This theory maintains that cell division is initiated by those substances which induce mitotic gelation and is prevented by those which inhibit this gelation, and that furthermore the mitotic gelation represents a type of clotting in many respects similar to the clotting of vertebrate blood. The bacterial polysaccharide of Shear, a substance which has a marked effect in causing regression of tumors, is a heparin or heparinlike substance. It prevents mitotic gelation and cell division in theChaetopterus egg. Dicoumarol has marked effects on protoplasmic viscosity, first causing enhanced gelation and then pronounced liquefaction. Its action on cell division is related to these effects. A synthetic vitamin K (2-methyl-1, 4 naphthoquinone) tends to liquefy and then markedly to clot the protoplasm of theChaetopterus egg. In very low concentrations it stops mitosis irreversibly.Aided by a grant from the U. S. Public Health Service.