The original intention of this study was to evaluate the plasma L. E. test1as a diagnostic measure in acute disseminated lupus erythematosus. As it proceeded, patients with classic examples of the disease were found to have consistently positive tests. However, the plasma L. E. test was found also to be positive in less fulminating cases, many of which presented clinical histories which were not typical for acute disseminated lupus erythematosus. For example, unusual combinations of diseases such as rheumatoid arthritis and epilepsy were noted in some patients with positive plasma L. E. tests. These clinical variations from the typical conception of acute disseminated lupus erythematosus suggested two important possibilities: first, that the plasma L. E. test is positive in diseases other than acute disseminated lupus erythematosus, i. e., that false positive L. E. tests can occur, and/or, second, that acute disseminated lupus erythematosus is actually a frequent, protean