Document 0gBgRv0YrqDk53jGz2Y0ZKDDd

December 16, 1935 Dr. E. A. Park Department of Pediatrics Johns Hopkins School of Medicine Baltimore, Maryland Dear Dr. Park: Please accept ray thanks for the reprint describing the roentgenologic studies which you and your associates have made in relation to lead poisoning. I am taking the lib rty of sending you a reprint containing a series of articles which describe our chemical studies in the same field, which may be of interest to you. During the past year we have been studying various parts of the same field which we have covered in our chemical work by means of the spectro graph. Our results indicate that the chemical findings are unlformlylow and that for any one analysis there is a loss of approximately 0.06 to 0.07 mgs. of lead. This means, of course, that our analytical results in the presence of l&rgy"amounts of lead have a very small error, while in the case of the urine and blood where the quantities are considerably less, the error is appreciable. Thus the mean urinary excretion for normal Individuals studied under laboratory conditions is ap proximately 0.075 0.08 mgs. per liter as cor pared to our finding of 0.02, 0.03 i>y chemical methods. I mention this merely because it may be of some consequence to you to know the precise sensitivity of the chemical method w ich we have employed in the accumulation of our data. Very truly yours. RAl'iIS fto'bert X. Kehoe, M.D. B0-8 1 C /? I 1'