Letters Sent to Cecil K. Drinker, March 12, 1924

March 12, 1924. Dr. Cecil K. Drinker, c/o School of Public Health, Harvard University, 55 Van Dyke St., Boston, Mass. Dear Dr. Drinker:= Some days ago, Mr. J. A. Singmaster of the New Jersey Zinc Company was good enough to call your attention to a problem that we have at our Plant. He informed me yesterday that the situation interests you and I am, therefore, sending you this brief sketch of the situation. We manufacture phosphorescent zinc sulphide that is used as a base for Undark radium luminous material. The final product is the zinc sulphide combined with very small amounts of Radium and Mesothorium. The radio-active element is measured in micrograms, the amounts varying in different grades of materials. Otherwise the material is the same. Undark powder sells for $1.00 to $10.00 per gram. I am mentioning this since the price limits the amount of radio-active element that can be used. For a number of years, up until 1919 or 1920, we maintained a large force of operators - girls - who applied Undark to watch dials, hands, and other articles. The process is strictly a painting operation. The powder is mixed with tree guar adhesives and applied by hand with fine brushes. Some time ago, one of the operators developed a jaw condition which later became a necrosis, and the young lady subsequently died. I am told that this could have been caused by phosphorus, tubercular infection, or other tooth condition. We use no phosphorus whatever in Undark. It is a highly purified zinc sulphide and contains microscopic traces of impurities which make it phosphorescent. This is principally copper. Late last year, another operator developed a mouth condition which at first was thought to be similar. I understand, however, now that the girl is very much improved, indicating that the condition is not progressive in this instance. I have also been informed that her family have had considerable tubercular trouble. Those whom we have consulted can report nothing to us in the literature on these subjects that would indicate any form of poisoning from zinc sulphide. Nevertheless, we must determine definitely and finally if there is any ingredient or if the material is any way harmful. Mr. Singmaster tells me that you are willing to consider this problem and I gladly seize the opportunity to write you and am having sent to you a few grams of the zinc sulphide. This will be despatched to you direct from our Plant in Orange, N.J. He tells me that you expect to be in New York in April and I hope to see you at that time. It would be akward for me to come to Boston during the next week or two, but I shall be guided by your wishes in this matter. If you would like to have a talk with me before coming to New York, I shall of course make it a point to see you in Boston. Yours truly, ARoeder-HM President.