Document 4JdaZrKBnR01d1yYM3nwX403G

KCfifBEV t MflTTIJOW COMPANY AIR MAIL MANUFACTURIRt Of AliUTOI AND MAONIJIA PRODUCTS SINC1 l73 A M I l (Ri PlAHlUVBNIA . June 17, 1943 PLAINTIFFS EXHIBIT K&U No. 2895 K. W. F. Shepherd, Esq. Turner & Newell Ltd. Spotland, Rochdele Deer Mr. Shepherd: Re: Dr. Leory TJ. Gardner's Asbestos Dust Experiments Further to your letter, T&N No. 2884 of May 15th, to which was attached a copy of some notes made by Dr. Francis after perusal of the outline of the proposed monograph by Dr. Gardner, I now hand you herewith copy of Dr. Gardner's letter dated June 9. 1943 to Mr. Vandiver Brown, Secretary of JohnaManville, roplylng to the questions raised by Dr. Francis. You will also note from the penultimate paragraph of Dr. Gardner's letter that he does not anticipate completing the final report before January 1944 on account of additional work, 'vdiich he feels is necessary, as well as the manpower short age.. ?our9 sincerely, em: ck Att. Copy by boat KEASBEY & UATTISON COMPANY V N c- 060 06 00120 0 p Y THE SARANAC LABORATORY FOR THE STUDY OF TUBERCULOSIS : of the Edward L. Trudeau Foundation 8aranac Lake, :H.-Y. June 9, 1943 Mr. Vandiver Brown, Secretary Johns-Manvllle Corporation 22 East 40th Street New York, New York Dear Mr. Brown: I am pleased to submit the following,comments on Dr. Francis' pertinent questions about our 4xperlaens\upon asbestosls. He is correct in assuming that these pointswlll be discussed in the forthcoming publication but for hi3 benefit I- will amplify them at the present time. The differences that we have observed between Bolivian and South African blue asbestos may not apply generally to commercial products, We worked only with small samples furnished us by Profes sor Larsen of the Harvard Department of Mineralogy, which he had selected because of their purity. In these particular samples the differences in fibre flexibility were very obvious; the Bolivian material being composed of a bundle of straight, stiff fibres over3 inches long while the South African sample was a block of mineral from which the fibres could be scraped off as a fluffy mos3 of fine fibre. In our effort to determine the effect of very pure substances we may have defeated one of our purposes. Nevertheless, I trust that the further experiments still in progress with the latter type of asbestos may establish the importance of fibre flexibility in the production of pulmonary fibrosis. : .The question of tuberculosis in association with as bestos Is one .that has been long discussed. All observers have been impressed with the very pbvioua differences in the incidence pf this Infection in American and English asbestos fabricators. T^have cor responded with Dr. Hereweather about this subject for many years and on the occasion of his recent visit to this country we discussed the matter at great length. Unlike silicosis, which is universally as sociated with an excessive Incidence of tuberculosis, asbestosls is apparently so complicated only In certain locations. In the United States surveys of asbestos workers have never revealed an usual fre quency of this infection. In Quebec the rates are high but as far as one can learn they do not surpass the generally high rate for that province. In England, the incidence of tuberculosis in asbestos fac tories is generally accepteu as excessive but the basis for belief is largely post mortem material. I know of no report based upon roentger ographlc surveys of large groups of living employees. While autopsy v \ CO 060 06 001 Mr. Vandiver Brora 2- June 9, 1943 studies are extremely valuable and as a pathologist I would be the last to belittle their significance, 1 cannot help but feel that selection of cases may have influenced the picture in England. The cases that die of tuberculosis in institutions are apt to come to autopsy but we do not know the proportion of the cases dying of othei causes that may have escaped this method of diagnosis. In animal experiments, done with Canadian chrysotlle, there is no such tendency to increased susceptibility to tuberculosis as. observed with quartz. In asbestotic guinea pigs, infected with tubercle bacilli of low virulence, the infection may spread for a time but after some months it generally heals with the formation of scar tissue which accentuates the fibrosis produced by the asbestos. In the case of silicosis, on the other hand, such Infection is con tinuously progressive and ultimately terminates in death. The result with asbestos much more closely simulate those produced by infection in combination with relatively inert mineral dusts like coal, iron or gypsum and various aon-fibrous silicates.- Not a few of Dr. Mereweather's cases of tuberculosis i asbestos workers oocurred in the same families. He sent me one group of specimens in which five bad the same surname. This would point to a strong familial factor and one cannot escape the conviction that th sane result might have been observed had these people been working In some oilier industry. Personally, I do not believe that asbestosis creates specific predisposition to tuberculosis or otherwise this effect, ar> in silicosis should manifest itself throughout the world. I believe that the exceptional English experience is a manifestation of the effect of more general social-economic factors that may pre vail among the workers in that country. -The question of carcinogenic action from asbestos is bj no moans settled. Gloyne in England is strongly impressed with its probability; 1 have always been most sceptical and it was not until ot chance observation upon mice raised questions that I gave it serious consideration. I hope tiiat we may be able to obtain funds for further investigation of this point. Until that is done I shall maintain the came attitude ana say nothing about our observation. I an sorry that confusion has arisen over the question of the effects of aluminum. The references to this matter were neces sarily abbreviated but they are based upon five years of experimental study of the influence of this substance and its compounds upon quartz These happened to have been started before we had heard that Denny, Robson and Irwin were using metallic aluminum, blit have not yet been reported. We hit upon the fact that colloidal alumina would effective neutralize the toxic action of quartz. Subsequently, we discovered th \ 060 06 00118 Mr. Vandiver Brown June 9, 1943 apparently only the alpha monohydrate of aluminum has this effect. Other forms of alumina seem to be quite inactive. The Ontario in vestigators found that in silicotic animals treated by inhaling meta llic aluminum, the quarts particles were coated with a layer of alumina as.alpha monohydrate. It would therefore appear that the metallic particles dissolve in the tissue to form the alpha monohydra and that this is the ultimate inhibitor substance. Since this is the case we have continued to work with this particular compound as we fo that it also possesses other advantages over the metal itself. ' f When we applied this same compound to asbestos the res were quite different from those obtained with quartz. 1 showed Dr. Uereweather our dissappointing results when he was here and we di cussed the similar experiments which King ani Belt are doing in Engla kr. Muehleck asks when the final report will be receivi It is my feeling that before publication we should complete the few experiments stiil in progress upon the action of different forms of blue asbestos as this is a matter of practical importance. I might point out further that a method for producing asbestosis bodies has recently been published which may enable us to obtain a sufficient quantity of these bodies to test their action on the lungs of suscept; animals. Should they prove incapable of causing f5.brosis, as I antic; pate, we would have further confirmation of. a protective mechanism. 1 in turn has an important bearing upon the matter of progressiveness oi asbestosis; if in the formation of the asbestos body the capacity of 1 mineral fibre to irritate tissues is destroyed, then there should be r profession after exposure ceases. We have already applied the new teclmique in the hope that we may obtain enough coated fibre for test. The latter would require another year for decisive results. However, we should have some indication of the ultimate outcome within 2 or 3 months and can then decide whether the final answer is worth waiting 1 In the mean time 1 shall start assembling the many illustrations that rill be necessary for such a monograph and will wor on the actual writing as fast as I can. In no event could I promise anything before January 1944* A curtailed.staff and the necessity for almost constant traveling- leaves few evenings that I can devote to the business of writing. V- I greatly appreciate Dr. Francis' interest and trust th the above amplifications have clarified the points that he has raised. Should he or any other contributors have further questions 1 would be happy to have the benefit of them in the preparation of any final re port. Sincerely yours, /s/ Leroy U. Gardner LUG:RBH Leroy D. Gardner, U. D. Director \ - -b L (,-'9 060 06 00119