Document zdJgLkRjL97Nvv53qZY9RdZV7

fe-ASBEY &. MaTTISON GuMI'A^ AMBLCm. r i 7:*. AV!* October 28, 1946 Confidential Mr. Vandiver Brown Johns-Manville Corporation 22 Ecrt 40th Street New York 16, N. Y. Dear Mr. Brown: Saranac La.bor=+'^ry Report on Asbestos Dust Experiment Thank you very much ior your letter of October 22nd tog-ether wnm copy of the Saranac Laboratory report dated September 30, 194S entitle; "Asbestos Pneumoconiosis" and also copy of your comments on the re which we briefly discussed over the telephone the other day. In addition, I wish to thank you for your letter of October 27th and for the kind invitation to be present at a luncheon in the Johns-Manville Corporation Board room on Thursday, November 11th, at 12:30 P.M. I accent with pleasure and will bring my copy of the report with me to the meeting. I wish to make the following comments: 1. I fully agree with the views as expressed in your memorandum sent with your letter of October 22nd. 2. The report is confidential and is the property of those who ad vanced the funds for carrying out the experiments at the Saranac Laboratory. 3. The report should be confined to the results os animals only. 4. There should be a separate later report, not a supplementary report, dealing with human asbestosls. 5. Experiments reported on to dale covering tumors and pneumonia caused by asbestos dust are inconclusive. The entire paragraph Nc. 52 on page 39 "Neoplasm" should be deleted, 6. The number of million asbestos particles (long and short) per cubi loot of air is, in my opinion, a more accurate and indicative measureme than the percentage of long fibres. Mr. Vandiver Brown 2- - Octo: r 7o me, after having studded the report quite caref-_.lv, th- follow:.-, are the most significant points: Paragraph SI, Page 34 - Comparison of Long-Fibre and Shori-Fitr-: Dusts. "Willi quartz dust it has been demonstrated that the smaller the particles, the more intense is the tissue reaction, and that there is little reaction to particles larger than three rr: in diameter. Ir. the C2se of asbestos, however, the rev-rsc is true and apparently only long fibres have any specific effect." Paragraph S7, Page 37 - Theory of Irritant Action of Asbestos Minerals "Ln view of this evidence it seems more likely that asbestosis is caused by an unusual mechanical irritation from long asbes tos fibres/' "Further support for the theory of mechanical irritation is that asbestosis occurs in an organ of high mobility -- the lung -- and that a fibrous reaction can be produced by injection cf asbestos fibres into the peritoneum, where there is also a de gree of mobility, but not in other extrapulmonary organs." Paragraph 90, Page 36 - Susceptibility to Tuberculous Infection "When the fibrous dust was being inhaled during the evolution of the infection, there was a spreading of the tuberculous pro cess for a time but usually the stimulus for continued pro liferation of the tubercle bacilli was not sustained, the pro gression was arrested and healing followed. Looking forward to the pleasure of seeing you on Thursday, Novem her 11th, and with best wishes, I remain sincerely. suck ec Mr. J. F. D. Rohrbach President