Memorandum to Mr. Roeder [A. Roeder], no date

138 Memor andum Relating to the probable causative element underlying the disease of about 12 girls formerly employed by the U. S. Redium Corporation at Orange, N. J. Origination of said disease attacking the gums and jawbones of operators and finally becoming systemic causing death ultimately, are associated with the painting of numerals and hands of watches, clocks, etc., with so-called self-phosphorescen materials using fortheir fixation, various dhesives and a camel's hair brush. During the process of painting, in order to keep the brush pointed, the operator acquires the halbit of shaping the brush by putting it between her lips and in so doing it is now suspected that a certain amount of self-phosphorescent material may reach and be de- posited between the interspaces of the teeth, gums or tongue thus causing or contri- buting to the ailment inquestion. Since in this process, the operator deals with sev- eral substances and is also exposed to various other irritative agents, it is well to consider each agent separately and the action they could have alone or in combination with others to provoks such conditions. Luminous Material The materials that each operator has to deal with are 8.S follows: UNDARK, a composition of phosphorescent crystalline zine sulphide compound containing small quantities of other elements such as copper, manganese, lead, arsenic, thalium, uranium, selenium, etc,; in order to render it luminous in the dark, it is mixed with various radioretive elements. The usual radioactive mixture contains radium, mesothorium and radiothorium. The usual luminous material an operator deals with most of the time contain various proportions of radioactive elements of joint radiosctivity equivalent to about I milligram of gomma radiation of radium element as an average, mixed with about 40 grams of phosphorescent zine sulphide in most minute sub-divisions; ultimate particles of radioactive elements being rendere insoluble in ordinary solvents. This also ap- plies to phosphorescent zinc sulphide crystals which are not, or very little, soluble in ordinary solvents. ADHESIVES - Most commonly used adhesives are represented by a solution of gum arabie in water. Luminous material is mixed with this adhesive and painted. This ad- hesive when put in the crucible for mixing is not sterile since certain smounts of it remain in the crucible every day and are used, with new material, the following day. Crucibles remain exposed more or less to air, dust, etc. Furthermore, the camel's hair brush is not sterilized before or after working with luminous material or adhe- sives and so also carries a certain amount of contamination from saliva and its contents. Conditions during Operations It is well to consider the process of "pointing" the brush by moistening it between the lips in order to estimate the probable amount of material that reaches the oral cavity. The small brush as used for painting, when dipped into the thick mixture of radioactive inc sulphide with adhesive, can hold, when fully dipped into the mixture, from about 7 to 10 milligrems of substance as a whole. The "pointing" of the brush, however, is done before dipping the brush into the mixture, or after removing as much of the mixture as is possible from the brush onto the side of the crucible. That is to soy that at the time of "pointing the brush does not hold more than a few milligrams at the most. When the operator "points" the brush be-