Document 7MOXxeD2opbyxNnOOvB4EvdvB

i *f Xarch 15, 1943 DEPOSITION EXHIBIT Dr. Ludwig Hektoen, Chairman. Committee on Cancer Research National Causer Institute Betbeeda, Haryland Dear Dr. Sehtceai . la analytic? the results or a recently completed f >Wg * it!on_ experiment on asbestos!a, X vas startled to discover that a snail group or 11 whit* aloe that had been ^ * ng- tabes- toe dust from 12 to 24 nonths aheved an excessive incidence (Sl.c2) oT pulmonary cancer. This experience vas quite at variance vlth the- results la.all our previous Long-term. dust exposures which were sumarized and published by Tcrwald and Xarr la the Aaarlcaa Journal or Pathology#- January 1933. X would have attached little significance to this recent ftnding because or the acall number- or an Inal a Involved, bat ror the ract that the literature now contains sons 10 reports or pulmonary cancer In cases of faesaa asbestcsls. 2ren these X hare heretofore attributed to selection or saterlal ae ve have found no eases of pulncsar? tumor In. surveys of employed asbestos vorhers. Sovewer, Cloyae, Xarsvether and other 5ngtih observers contend that asbestos has a specific carcinogenic action on the lungs. The question la of considerable Importance In Indus-- ... trial medicine- because of the associated compensation aspects and . from & scientific: rlev point. It Interests me a great deal. Xa view of this recent finding X have reanalyzed the results of a large number of dust Inhalation experiments that ve have carried on during the past 23 years. The incidence of pul monary tumors la shown in the appended table. It would appear that, except In aloe, tuners have been generally unoemmou In the* strains-- - of different species that we had used. Guinea pigs have shown oc casional adenomas of the lung whose Incidence la not Influenced by . dust exposure or by the type of dust Involved. Eovever, in white ' \ mice that survived for 13 or more months in our dust rooms, various \ forms of lung tumors were much more frequent. The average Incidence 'Of such tumors In a group of 143 mice exposed to 4 different quart z- tontalnlcg dusts vas 13.82 but this appears am all in contrast to ~hls Incidence of 81.82 In the asbestos nice. In 51 younger sice 'hat died or were billed after exposures of 10 or 11 months there s only one Instance of pulmonary tumor. Therefore, either age or a..%atlo of dust exposure must be Important. PRODUCED . JM-83 010253 A Dr. Ludvig* Sektoea -2-- Xarch 15, 1543 Sons of these experiments was planned to study* caeclmogenic effects. HIce vers only used as there vaa soace in the dust rooms and many of these animals that died after short exposures vere discarded without autopay as they could not have developed a 'ficient anouj ` " -3t reaction to be of interest. The strain of nice kept in the -abcratcry has changed fron tine to tine by pcrtation of nsv 3tock- At one time ve did procure from Dr. Rand Sly sore csroer susceptible stock but as these an.lan.Ie failed to react tc inhaled quartz vs lort Interest In the subject. under such ocnditions, the results with asbestos rear nothing hut in view of the considerations which I have cited. Z believe they should be checked. A decisive answer to this questis-s vculd be of real practical value. Proa what ve have learned about the action ef a3bestifom ninerala In the living tody, I would sot be surprised tc discover that their carcinogenic effects are dif ferent from those of ether minerals. Their crystallographic structure is unique. They apparently act as mechanical irritants rather than chemically as is the* case with quartz and other fame of free silica. Ca crushing or grinding, asbestos fibres loose parctically all their irritating capacity; quartz cn the ether hand, beccses acre, irritating as the particle also decreases. Asbestos provokes fibrosis only in the lungs of certain species; quartz excites such reaction in any* organ of any species of animal that ve haTe tested. Asbestos seens to have no specific action upon pulmonary epithelium but in soae species, it caus-?-~ an unusual type of diffuse fibrosis which cocpresses and distorts the epithelial-lined respiratory bronchioles but often fails to obliterate them. However, this aechanisa would not appear to be the one responsible for the* mouse tumors for this Is one of the species which develops no fibrosis on exposure*. Possibly, the lack of reaction is due to stxp-srior'Upper respiratory, protection against inhaled.foreign bodies^* The., lungs of aloe, exposed to asbestos dust for two years reveal relatively few fibre and all of these are short and eoated to forn that peculiar . structure* known as the asbestos body. : In order to verify our accidental discovery of pos sible carcinogenic action of fibrous asbestos, I would like to repeat :he souse inhalation experiment under properly controlled conditions. * would breed a large number of cancer susceptible aloe, splitting oh litter into three groups and keep a record of the ages of each. ~ 1 third of the offspring would be kapt in a normal atmosphere as a .: .trol; another third, would be exposed to quartz dn3t as a second .* 'rcl and the other third, would be exposed to asbestos dust. Ve PRODUCED 00010235 JM-83 <?/ OM * 3r. Ludvig Sehtoen Harch IS, 1343 Yould at tespt to obtain 5C0 nice for each group. The expo aura a would a;r psrently have to be continued for IS to 24 Booths. Cur routine In such experlneats provides for dusting: S hours a day, 5 days a veeh. hare all the necessary eqoitaent for such ex periments and a trained laboratory personnel, Ponds are lacking hcverer. Cur prerloua study of aabeatoals vhlsh continued for a period or 7 years was financed by the Asbestos Association. Since this group af nacsfaaturers has already Invested |3C,CC0, I cannot ash then for further contributions. 1 discussed the natter vith Ur. Shades at the Hescrial Hospital who favored and was of the opinion, that It van worthy or consideration by your consittee. I as therefore applying for a grant of *5,0CG to cover the cost or the first year's expense. .. ' , ' ... - ' Xhad told Sr. Hhedes that 1 vcnld be willing to do the entire experinent for this asount and ordinarily Z should. How ever, on cy return fsva Hew Tort, I found two proposals for Investiga tions or other Industrial dusts each or which yield the Laboratory #3,GCO a year. As X have only two dust rooss at the present tine free for nev work, X cannot afford to tie up one of thea for two years for half ths anoust. ` . you be favorably Impressed with this proposal X would appreciate any arltiaissa or suggestions. - Sincerely yours, - LTOtHHH y-Ss-DsDirector 00010236 PR00UCE0 JM-83 010255