Document V38dGKkqQnQb6xnjZQNz6OwBw

,October 25 1931*. Mr. G. E. Willoughby E. I, DuPont de Nemours And Co* Wilmington, Delaware Dear Mr* Willoughbyj X am sorry X neglected to fully answer your letter of June Ijjth concerning blood lead-levels in the cancer patients treat ed with colloi dal lead preparations. For a variety of reasons, it was not possible for us to follow these blood lead-levels, and we have no data on the subject for these patients. We are doing as much work as we can on the problem of blood levels in normal individuals and in patients with varying degrees of lead absorption, and I hope soon we shall have some useful information on the subject. At present, however, our information Is not sufficiently wide to be very useful except in the case of normal individuals, and even there I am not wholly satisfied since there was some possibility, thought indeed quite alight, of contamination due to the use of ordinary needles in withdrawing the blood* I feel quite certain that our basic data are essentially correct. I would not be entirely certain that an occasional result a little higher than the average might net-he due to chance contamination In the course of collection of the sample. Cordially yours. RAK:IS Robert "a * ke'Koe, M.D.