Document YD57w7M6G6QGeXVzDp8nQwaRE

April 1 5 j 1948 Miss Arlene larks, Frigidaire Division, General Motors Corporation, Dayton; Ohio. Dear Miss Parks: ,, Just ih case you do not have it, I am sending you a mimeographed sheet which will give you all the information that we can offer on the stain which we commonly use for blood smears. In ourJexperience the stock solution of stain does not deteriorate, or at least it deteriorates very slowly indeed on standing. In any case, the stock solution that we make up does not last long enough to show any marked effects of deterioration. Some slight difflenities occur from time to time, and what we do under those circumstances is indicated in the paper which I am sending you. If we should have serious difficulty with a particular batch, we should be likely to conclude that something was wrong with one or the other of the products, or that the reagent bottle had not been entirely free of some contaminating mate r i a l . Certainly if we were .0 have serious difficulties, we would merely make up a fresh batch of stafn and begin over again as you have done. I shou d point out that we would not be willing to rely upon the exam in-ation of blood films as a means of estimating the risk of lead exposure in a group of men whose work involved potentially dangero us conditions. It is not possible, especially in individual cases, to arrive at any very satisfactory conclusion as to the extent of lead absorption from this procedure alone. Indeed we find that these results may be quite misleading. I am not saying that th e method is without some value. I am quite prepared to say, however , that it is hpt to be depended upon under conditions of dubious or hazardous lead exposure. Cordially yours, PAK ef Enc. Bobert A. Kehoe, M. D. N 6185