Document Lpqz0naaDEXMVzw6rmRJajoJg

June 13, 1941 Up. -Joseph kelson 120 -last 39th 0treat Hd'ti iork r Dear Doctor Felsen: I aia sorry that I did not havo a chance to see and talk with you in Cleveland. However I was only there for a short tl -e and prac tically all of ray tine was taken, while I was there in talking with various people about our exhibit. 1 was interested in what you had.to say about the discoloration of the Intes tinal nuoosa. Actually I have never had occasion to look for the condition you describe through the use of the proctoscope. I have seen this condition in experimental animals and I have no doubt it exists frequently in the human being. I have had occasion to 3o this condition in the external anal tissues and I think there is very little question that it is discernible much more frequently than is a lead line in the gingival tissues. I shall be very much interested in your article but X am afraid wo shall not be able to contribute much in the way of additional information. One reason for this is, of course, that all of these observations have as their purpose the detection of abnormal quantities of metal as a means of estimating the magnitude of the exposure to metal compounds which give rise to a black sulphide in the body. Our own experience has been chiefly with, lead but we have also had some interest in this same problem, particularly in the case of bismuth. In both instances, however, we have had facilities for the determination of the magnitude of the lead exposure In very precise terms, as determined by the study of the lead content of the excreta, blood or tissues. Having such infor mation we have pot failed to Jake the usual observations as to the existence and character of a lead line, but we have not resorted to the use of the proctoscope. I may say furthermore that although this is a very in teresting and, I think, useful procedure, it could hardly be used regularly or even frequently In industrial practice as a means of detecting evidence of abnormal lead exposure. 2 Ho doubt you will realize that one of the most important aspects of our work has been the practical consideration of how under industrial conditions one could determine the existence of hazardous lead exposure. This*, we believe, is done more effectively by the study of the lead content of the blood or of t'.io excreta, than by any other means. Cordially yours. RAKsis Robert A. Kehoo, M.D. 0015643