Document XzRvO6RBj819KoBbGO0a3E9yw

2li. Sunraarr and Ictertrstatfon of Inhalation Leerricant with Floata Dujst The findings ia ths expari.Tnnt with Jting's floats dust, can s\iE3arised 'under three heading** A. Effect of the inhalod dust on normal aniraJ-3. Tha flog's float* dust caused a chara.C'teriatic peribronchiolar fibrosis in guinea pigs bat not in rabbits or rats, Tte fibrosis did not progress aftar the dost exposure was discontinued. and the guinea pigs transferred to noraal air* 3, Sffect of tha inhaled dust on tuberculosis in guinea nigs. In guinoa. pigs in fected with attenuated tuberclo bacilli snd then placed la tha dart roce, the results were sorts -rariabla than ia usual'in an experiment of this type, l few animals showed co sign of progression; in .-cost of then there was eridar.es c tea-. ( v Fcrcrp progression frith o?ibsequant healir.gy in one animal there was continuous / progression to death. In contrast, when guinea pigs, after being infacted, are exposed to quart; instead of asbestos dual, the infectious procasa continues to progress and srwr.tua.llr rsnises the death of the animals.. On the other hard, ex posure of infected aniswi* to .% harmless dust liV,* calcite or gjpsum do not load, to anr progression of tbs infection. Quins* plgff infected with atterroat^d tubercle bacilli following tha tamioAfcion of shout two rears' exposur-e to asbestos dust did net darrslop proersasirs disease. The onlj modification of the infection wa5 in its Local! action, * few b7.ci.1lX baing retained in the fibrous tcrminil bronchiole* sod forairu? tubercles there in addition to the uovaI foci beneath th* pleura. In view of this Yarisbilitj, the unusual nature of the response and tha high proportion of doatha Tran, intarcurrwifc po.cngapla. it is felt that deficit* condi tions as t/> the influence cf this dust os the course of tuberculous infection are not Justified-