What if multiple sclerosis isn't an immunological or a viral disease? The case for a circulating toxin

The literature contains studies on many causes of demyelination: Vascular occlusion--exogenous toxins--allergic reactions--and virus diseases. There remains, however, a small group of conditions which seems to have been ignored almost completely in discussions of cerebral demyelination. These consist of brain damage apparently resulting from some toxin liberated within the human body and not obtained from the outside.