The blood of the insane

The history of serological investigations of the blood of the insane is traced from the initial such study in 1854 by a solitary Scottish asylum physician, who counted the blood cells of his lunatic patients under a weak microscope, to the January 2005 announcement by an international team of geneticists of the development of a genomic blood test that can differentially diagnose schizophrenia and bipolar disorder. The story of the first claim of the development of a blood test for madness in 1912--the Abderhalden defensive ferments reaction test--is related in detail. Studies of the blood of the insane have followed four general methodological paradigms: the corpuscular richness paradigm (1854); the metabolic paradigm (c. 1895); the immunoserodiagnostic paradigm (1906); and the medical genomics paradigm (2005).