In a report on lead poisoning published in 1925, Aub, Fairhall, Minot and Reznikoff1drew the following conclusions: Most of the lead absorbed into the body is deposited in the skeleton, where its behavior resembles calcium in many respects. Stored lead is apparently harmless, but the skeletal deposits may be released by a slight change toward either the acid or the alkaline side of the usual hydrogen ion concentration of the organism. They proved that abnormalities of diet or certain pathologic conditions bring about such changes and so release the rather unstable deposits of lead, flooding the organism with soluble lead. The mechanism of acute toxic attacks which occur in lead poisoning as a result of infections or of acidosis is at once apparent. This study of lead in relation to multiple sclerosis was inaugurated in November, 1932, by the discovery made by one of us (W. C.) that