Document omdv2YLRV0B1yrKkKwzdBRZYr

lagnat 19, I9kfl Hr. K. E. Jackson Safety fegineer .. 22 East. UOth Street Hew Tors 16, II. I. *^ Set Dominic Bertogliat f Saar Sr. Jacksoni We hare forwarded our report concerning the above case to Doctor Berdex, Pathologist, St. Haiy's Hospital, L29 East Third Street, Dalnth 5, Blsnuota. la yon will recall from previous correspondence, he Bade the material available to ns for study and requested a copy of the report concerning oar findings and interpretation. Although individual susceptibility has been mentioned often to the variable incidence of pulmonary daaoge in a group of employees sinllsrly exposed to harmful dusts, nevertheless me have never been able to dcnoBstrate the existence of natural or hereditary factors which sight account for such variability. Ex perimentally, different of the ease species react essen tially the same to alwllar exposures. La tanfcrH mti et4iw) however, there are acquired factors which play a significant role. The major one of these is of the respiratory system, lhethsr active or healed, it say alter the ^ anatomy and physiology of that system thereby alloeisg greater mograss of ths harmful agent into the lung permitting excessive pal mary retention and stimulating inflammatory reaction. In addition, there are other iiialnilx Important factors, including previous dust exposure, ehich say modify the reaction to other dust Inhaled in snhaaipwit unrelated exposures. Thus, the bituminous coal minsr aad tbs hematite sdner react differently to silica than do those without previous exposure to dust. Age and general; health might also be aalntained as acquired predisposing factors. H. U. Jackson Jnhm-Mirr"* ^^ * Corp* .iuirust 19, 19US r^Ro 2 In general, it is aost difficult to evaluate the role of iadiideal susceptibility as a determinant of the pulnonary condition resulting fro* exposure to a dust. It is clearly established that the sineralogie coaposition, the particle size, the atucepherie coo-- cantraticn the duration of exposure are of prune importance in the etiology of any pulscnsry dasage resulting frua the inhalation of cust. ^ In consequence of the above, I can see no other alternative than to anticipate others sith similar exposures to be similarly affected, but I expect also that individual susceptibility -will ef fect sosa selection* Sincaral7 Arthur J Tarsald, H* L. Director m v. na- rv. v