Document dgEX27KypLrdbxdg2MMNn5MG

infundibular passages, they aro also present m mo rnsnoni Vivas, in tho neighbourhood of the phthisical cavities, ami somo can bo demonstrated in tho fibrotic areas surrounded by defmito fibroblasts. Ono in particular (seo Fig. 12) measured about 75 fi. It is clear aud segmented in its middle part, but tho extremities are nodular and dubbed. It is difficult to.imagino tliat a foreign body of such longth could bo transported by phagocytes, but they may represent larger bodies left in a bronchus which has hecomo obliterated. Tho bodies haro boon oxamined with tho micro-spectroscope, but so far no cluo as to their naturo has been obtained by thia means. They aro aot refractilo by polarized light. Nature of the Bodies. ' Wo hare shown these preparations to several patho logists, but tho appearances are new to them. To coofirm our own opinion we havo submitted them to experts in zoology, who are unanimous that they aro not of animal naturo. Wo havo also submitted them to botanical and chemical authorities, and though thcro has been a consider- alio difference of opinion, some regarding them as hypho- mycetes,. tho general opinion has been that they are not vegetable forms. ... * . 1 The fact that exactly similar bodies hare been found in tho lungs of another asbestos worker, and, so far as X can ascertain, havo not been found elsewhere, would seem to indicato that they aro* essentially derived from or associated in somo way with tho asbestos itself. It is also certain that they do not in any way resomble concretions, largely com posed of calcium and other salts, andginlso containing iron derived from blood, such as havo been described as strepto tlu'ix forms in tho spleen, and which may closely simufato mycelial 'filaments. Tho hypothesis advanced is that these bodies aro portions of asbestos fibres in tho process of altera tion aud absorption by hydrolysis, either by direct chemical action or by enzymes. Tho particular variety of asbestos with which this patient worked was a Canadian serpentino (chrysotilo). It would probably contain silica and a magnesium salt ip .^bout equal proportions (40 per cent.) with up to 3 per'cent, ferrous oxide, 1 per cent, of alumina, and water. From its high resistance to heat wo aro apt to regard asbestos as indestructible, but, given time, it is possible for hydrolysis of such silicates to occur, even in pure water. Such hydrolysis would bo hastened and intensi fied by tho prcscuco of CO, in tho pulmonary alveoli, and Jio warm moist atmosphere there would, no doubt, accclerato die process. Even under theso conditions tho process would loecssarily bo a slow ono. Tho magnesium could bo teparated out as relatively insoluble carbonate, or moro tolublo bicarbonate, which in turn would be converted into my other salt for which thcro happened to bo tho appro priate acid available. . Tho iron existing in- a ferrous condition in tho presenco >f an oxidizing agent' might bo converted into tho forrio itnto, and subsequently precipitated *aS hydroxide. Tho dltcn might pass into a colloidal state, at first in sol form "(orthosilieic acid), later passing into a gd (metnsilicic acid). If this were so in sol form, it would tend to remain associated with tho surfaco of tho asbestos fibre by adsorption, and might bo held thcro till it bccamo a gel. Iu timo tho gel might adsorb tho solution, and so gradual conversion of tho fibro into a mass of gel would occur. Thcro might bo iu tho tissues sufficient albuminoid material to effect rapid gclatinizatiop of tho sol, particularly if, as would bo the caso here, tho sol was being slowly produced. Tho fact that the gel is of high surfaco tension, and funned at an irregular rato, would giro it a spheroidal structure and account for somo of tho appearances seen hero. Whether this bo tho exact explanation or no, it is at least an hypothesis which should bo capablo of experi mental verification. As has been hold by Gvo and others, in cases of silicosis there may bo a direct chemical action of silica on the tissues apart from the merely mechanical irritation of tho particles, with the production of fibrosis. Oithosilicic acid is, as has been shown, an activo poison, but rapid couvcrsion into mctasilicio acid would mininrizo its action. _. As to tho rulutivo part played by tho asbestos and *J*o kHiimi.iumi.') Mill IWUH in M1I.1 1.4W1, (11 ruiuuou to change, it is difficult to say, but it is a rcasnnabl^SSTu tion that the tuberculosis was a superadded infection, ari!*i in Dr. Gricvcs's caso referred to above thcro was in i}.,, sections oxamined a considerable degreo of fibrosis witiio:'^ apparent tuberculosis. Tho iminediato cause of death i-\ that caso was a tormina! broncho-pneumonia. Till sorul* experimental work is completed tho oxact naturo of tin** foreign bodies must remain in doubt, but their hi--Ut-v characteristic appearance may well prove to bo an impor tant diagnostic point in tho recognition of tho lucg of * worker in asbestos* T urn much indebted to Dr. Cooke for material from his at* to Dr. Griovo for an opportunity of examining his mierotcenkA sections, to l*. L. Robinson, D.Sc., of tho Chemical Dcpantiwi,, Armstrong College, for bis advice and suggestions on the ehcmmtv of tho sifieates, and to Professor W. ft. Lang, of ban. Chester, for a reasoned opinion as to tho Qoa-ootanical aaturw v; Uio foreign bodies. ' - * CLINICAL ASPECTS OP PULMONARY ASBESTOSIS. _ . . ST- . . Sat THOMAS OLIVER, M.D., F.R.C.P., Consulting Physician, Royal Victoria Infirmary, Newcastle*** Tyae; Emeritus Profcssor of the Principle* and Practice . . . of iledkine. University.of Durham. . . Dit. XV. E. Cooks has given a short account of .tho history of asbestos, also of tho processes of Its manufacture into cioth-liko structures much in tho same manner as raw cotton fibro is woven. He. has told us that in the cardin * department a considerable quantity of dust is evolved. The crushing of tho rock is not carried on to any extent is this country; tins is usually done in tho countries where tho mineral is quarried. Canadian rock is crushed in Canada so as to reduce tho expenso of transport t,, Great Britain. Our workers aro thoreforo less exposed :o tho harmful infiuoneo of the dust--a fortunato eircau.- stancc, since tho rock frequently contains as much as from 50 to 60 per cent, or moro of silica. - With tho exception of Dr. Cooke's paper on pulmonary asbestosis published in 1924, and tho details of a fatal rs>o published by Dr. Montague Murray in tho Charimj (7 .j Hospital Gazette in 1900, thero has not-been, to my km.*, ledge, anything written in this country upon tho suhjet I havo had, however, tho opportunity of visitiug asU-u>* factories in America, and of seeing cases of puluwuaiy asbestosis through tho kindness of Drs. Qaudow and Griovo of Armicy, Leeds. It may, I think, bo safely said that thcro must havo been several deaths of workers i:i British factories from tho malady, but as uo autopsy ami micruscopical examinations of the lungs were made tie deaths woro probably certified as pulmonarv tuberculosis. Asbestos manufacture is largely a familial occupation. It has been carried on in this country only for a litilo over thirty years. Carding and spinning of tho fibre aro important processes in tho manufacture of asbestos good*. In theso departments many women aro employed, mothers boing succeeded by their daughters. Whcro ventilation .J tho carding and spinning rooms is properly attended to tho atmosphero is fairly clear of dust and floating fib?*.', otherwise in these operations considerable quantities of dust becomo suspended in tho atmosphere. In a lltiihh factory tho dustiest process is ** hand beating" of t!.o finished mattresses used for covering and protecting the internal machinery of automobiles. This work should only bo undertaken in a room separated from the main parts of tho factory, with open windows at ono end ami strung down-draughts at tho ofhor, but oven with this prccautiva men working therein should wear masks. Recently, with Dr. Cricvo of Armicy, I examined two women who are tho subjects of pulmonary asbestosis, *:: aged 48 and the other 39. Tho older patient was cue *f tho first to eommcnco work thirty years ago i particular factory I visited. At that date no danger fr- -j dust was anticipated, so that no effoelivo ventilation tho workrooms was attempted, such as prevails ti*lar. Although only 48 the first patient mentioned looks nkhr by several years, am! is extremely emaciated. She up work a year ago on account of increasing physK.u