Abstract
Summary: The etiological factor responsible for the demyelinizing meningoencephalomyelitis which occurs in guinea pigs following a single subcutaneous injection of a water-in-oil emulsion containing killed tubercle bacilli and brain is apparently a heat-stable, phosphatide-like material present in the white matter of the adult central nervous system. The active material does not seem to resemble any of the five previously described brain-haptens, except possibly the alcohol-soluble one. The mechanism of its action is not yet known, nor is the relation between the experimental disease and the various demyelinating diseases of man known, except perhaps for its similarity to the paralytic accidents following rabies vaccination.