Document qdLnpg0onRzppOzN4g5m0m7Vn

7 for bud narrow) wearing, wel, not accurate liaci the figur* has been ^ raised by dust from a neighbouring di7 cloth boa. hfaUress ButVia; without any precautions, (uch u axhauat ventilation, or damping fioor*, table* and *010111, follow* out with * figure of 1.S3 (See footnote Table S). Application.of exhaust, ventilation, and damping reduce* the figure considerably, but it but be that the figure* la column* i end 10 are too low, tiaoe oousu for aome subsidiary proemes, ittch u buttoning, aewlag, and cutting oat, an aot available. } It will be obeerred that carding, although essentially a very duity proeexi, produced a eoeparatire figure of only 1.17. Title ia duein part to partial andoeutt of Uu working parte of the carding machine, hot it taoctly the remit of the applicatioa of local exhaust Tenlilation. Moreover, the figure doe* sot take into account tha aztremely duaty oporatiou of (tripping. fieldtire to the comparative Dumber* for tha other different prootua, the figure of 1 for epinning, plaiting and braiding i* probably rather too high, owing to contamination ay doit from neighbouring and nor* duty processes. Sample* of a*be*toa vary much in chemical couetitutiou and physical pro- Cirtiea, and of the throe main varietiee, ehryaotUe, eroddoUle, and amodte, the iter two, in the opinion of experienced worker*, oaaally tire rite to more due than chryaotile in the textile manufacturing proorosu*. no evidence ni found to indicate that any oaa of tha throe varicue* ia more, or leas', potent than tha other* in producing fibre*!*, other factor*, such a* ooocsutratiou of dual, being equal. A peculiarity of (ho aabetto* fibre ii that it first fragment* longi tudinally, and apparently thia process can go on indefinitely, aince there it so ultimata fibre comparable to a vegetable fibre ouch a* cotton. Cenctntraiicn #/ Ihut cad Lrufti / cycnr Jfactuary ta Predvi* fiirttu.--Yrosz the data ao far examined it oeern* clear that bhroeu of the lung* ia a definite oouupational riak among*', atbeato* worken a* a claaa. Furthermore, it appear* that the riak fall* meet hearfly on throe longest em ployed and on throe engtged ia tha more duaty processes. Soma farther consideration of these two important facto**, length of em ployment and concentration of dust, ia desirable. Obviously, to some extent, they axe interdependent, aince, a griming that a (pacific quantity of aiheeto* dual moat be faVslwt to produce a generalised fibrosis, the fibrosis will result from exposore for a period of time varying with the concentration of dust is the air breathed. ^.Simsoa" report* the cate of tut aihrotro mill worker iu South Africa, txproea for 12 month* to a very duaty atmosphere, who died from a rapid tuberculosis; section* of tha tune* showed, apart from tha changes due to tuber culosis, a moderately marked fibrosis.1 Burton Wood and Page" report the earn of an^tabeams apinner, employed 13 months, who died from a generalised tuberculosis, 6 month* after oeaaing work. In tbit cate a little fibrous tissue wu generally to be men surrounding tha ubeun* fibres found in the lung tiude, but there was no gross fibroma. It seems probable, therefore, although further research is very suucasary, that not oaly u a certain minimal quantity of tha dust required for the production of a featrallied fibrosis, but that inhala tion of the dust in high concentration results tn the production of a more marked degree of fibrosis in a shatter time, than when the oonocnlration is low. Investigation of this important matter--concentration of dust and length of expo*ura necessary to produce fibrosis--from the clinical side is beset with difficulties, one of the most confusing being that the "existence of a clinically Koognuahle diffuse fibrosis is quite compatible with contioued work in the industry, and, therefore, the eases of fibroau discovered in such an investigation at this are in various stages of the disease, with the result that the point at which they first became recognisable clinically eaonot be ascertained. Despite this, same confirmatiou of the hypothesis that the length of ex posure to asbestos dust uwesaary to produce norosis varies inversely with the rouccntration of the dust io U air, within certaiu low and high limit*, mav be ebuinod.