Document MJXdjwnpm97bvYqeDygqpqJ1j

o 16 months a dolioato fibruLS raado Its appoaranoe. Tho process evolvod gradually and tho number of fine intercollular collagenous fibers steadily inarcaood. As tilln fibrosis contracted, it partially closed and distorted tho alvooli, uml with this change tho alveoli booaiao .ilnod with cuboidal coils. TUo ror.ult was on adenoma--like appoarance which froqujntly ac companies chro.vlo pulmonary in riammation resulting from many causes, il described a similar atruoturo in the lungs of guinea pigs in haling silicon enrbido. The longer exposures to asbestos r< sultod only in more thickoning of tho walls "of the air spaces, largely due to an Increase in tho amount of fibrosis. Tho fibrous tissue alwayo remained oollular and failed to chow the hyallnization oharaoterlatlo of silicosis. Ashes- , toaia bodies (fig. 3), first aeon in tho lungs of the guinea pigs that had inhalod duct for about 2 months, beoamo more numerous and more di s- tiactly sogmonl'jd with increasing exposure. Tho reaction produood in guinea pigs oxpoood for 6 end 9 months did not progress significantly during a subsequent poriod of 55 and 37 months when tho animals lived in a normal otinocphoro (figs. 6 and 7). Between. 8 and 11 months aftor oxp03uro coaaod, tho collular roaoticn In the lung had been completely replaced by thin atrando of fibrous tiesue. At I . , * t M` * later periods, tho acar tlotuo was loss in amount but In tho last animal sacrlfiood, 37 months after discontinuing dust expocuro, some fibrosis van still visible. 1 ~r* 1 ..................... 1 it' 10. 'Uillla, n.s. ................................--... ....-I .i nnd Brutaaert, P.i -- ... . . Tumor-liko Struoturos in tha Lunga of Guinea Pigs Artificially Expooed to Silica Dust. Am. Bov. Tubore. 17t 2C8, 1920. 11-' - rc