Document yrKdE4aJQrOZMXVGLYbvzyJpX

73. Rate and ?rne of faction. All fgut ar.irala sacrificed at 25 tenths showed a well-marked peribronchiolar fibrous. It,\ Uj 15-wnth anisal, reaction vus just beginning. isbestesla bodies were practically absent at both 15 and 25 aonths although two small 33100th bodies war* found In the 15-sionth aniaul after z long socrch. Thus, these anlnala exhibited fibrosis without asbeetosis bodies. 7U. Hice. Oat of 20 white slice used in this experiment, 11 lived & year cr aaro in chirl and died or were killed without showing an appre ciable degree of pulmonary infection. !$ Rate and Typo of Baactlon, Reaction was Halted to phagocytosis by oonotrueLear colls. Usually these were wide ly scattered through the sir spaces j & liadted nintsar were grouped about the ter minal bronchioles producing son* thickening of their walls. There was no sug gestion of fibrosis. The striking feature of the experinant was that 9 out of the 11 nice (82 per cent) exposed to dust for a year or care showed pulocmary turners, usually adanonetoo- in type'. These lesions did not contain dust or esbestosls bodies. Numerous asbestosis bodies wore observed in anir.au; killed late in th experi ment, Thus, these aidnilf exhibited antes to sis bodies without fihroeie. 76, Suaemtt and Interpretation. The perpeae of this experinant was to evaluate the Importance of long fibers in the tissue response to inhaled asbestos* The results indicate strongly that long fibers are chiefly responsible for the reaction. Thus, in guinea pigs react ion developed earlier and became acre extensive than in previous experiment* in spite of a ewaller concentration of atoo spheric dust and a lower ninaral con tent In the lungs. Furthermore, a. typical peribronchiolar fibr< ------1 J