Abstract
In vitro exposure of normal leukocytes to several procedures, among them heating to 58C with high molecular polyvinyl alcohol-polysulphuric acid-ester, produced changes morphologically identical with those seen in the peripheral blood leukocytes in acute disseminated lupus erythematosus. The theory is advanced that these changes in vivo depend on abnormal mucopolysaccharides which combine with gamma-globulins to produce Haserick''s factor.