The clinical course and symptomatology of the rare industrial disease due to inhalation and ingestion of dusts containing manganese are now well known. Edsall and Drinker,1and Edsall, Wilbur and Drinker2had an opportunity to examine a larger series of these patients than has been available to other investigators, and they summarized their observations as follows: As we have seen chronic manganese poisoning the following findings make the syndrome. We have numbered them in the most common order of appearance. It is difficult to emphasize in any written description the clearness with which the symptoms come out and the ease with which the diagnosis can be made. A history of work in manganese dust for at least three months. Languor and sleepiness. Stolid, mask-like facies. Low monotonous voice. Economical speech. Muscular twitching, varying in degree from a fine tremor of the hands to gross rhythmical movements of the