Document Lp0KNGeNz5VOYXpd28Z5qgw2g

rxmjutu.'fnjj qnpnnittnqgiamiUMgaggqm3l^JWBBBainaBBSHHl*v^ '940 illi* rnch rntintrtl vnlnal|t nnlhra- of 592 "ml that ml 76 to lilts 145, ntpanicd larly Inrc avail * accordmajority pncmnoirc from ltlnsis occurred prrsent. r, it was c disease st group 22 per it. of the a killing Analysis >' 'oris '!> >n nm ix years, sr in tin upbeat* .1 t folio" nplirntrd nriimo- nnini* 9r \Prrrmhrr r949 ` * WYERS: Asbnunh 6j! nevertheless that a considers! Ic number of men who develop complicated pm rmnoconiosis when f pged 30 to 40 are a very had risk. Tuberculosis was present in jf> per cent, of all pneumoconiotic ' deaths, in if> per cent, of all d rnths due to simple pneumoconiosis, and in 39 pc 1 cent, of all deaths due to complicated pnemnocn ninsis. 'The figure | (\(> per rent.) of the extent bf complicating tuber* * culosis in coal miners' pneurr oconiosis is higher than the figure given by Hooding and others, hut it is considerably lower than the figure for other industries, especially for slate mining in North Wales where tuberculosis is present in 75 per rent, of pneumoconiotic deaths. Finally, one is impressed by the apparently in creased susceptibility of coal miners with simple pneumoconiosis to pneumonia and acute respira tory infection. \ ftinuottRAruY hAi.oAiniF.s. E..nixi.rnca o., jary. j., nj nadiras, r. J*k (i04*), ftnur Mrrtrrttl* Atimrtr, a, 1:1, [pUMMlNR, R. LYI.F.. ind SI.AUDEN. A. F. (i<jjo), J. f Poth. * n.trf.. 33. 1*AMA7,IAN (FII.S). PIERRE (1047:. ' Rrrl.trrlir* Sor l.r ' l'nr\tmitknu<or Dan* l.e* J DAVIES, t., nfl MANN. It- (MM*). ' Procrr.ltn** of the Ninlh Inlrr n*lioii| Conffrf** on ln<lo1rii Mriticine.1 (In th* prfi* ) t pi .FT(_1 ir.n. C. M. ( mm*), fit it. Atrtf. .7-. *. 1015. tooj. M;noniNr:. <*. (J. (191S), ijttHfi. a. ftoi. fsMITJI, c;nni)ON, 1`fMnml mnnnnrrtion. tCOl'GII. J.. JAMES. \V. R. ......... ,1 WENTWORTH. J. E. (hmo). A ('nmr**r*non of !ho Hndir>l*>ir*l nttd l`llmli*Birl (liupr in \]ol Wokrr*` I'ikiih' n frtutnol nf the I'nruhy rtf llrtiiinlnfiitt, I. I. r<;m-(;onY, J. C. t*u). F*K*i. Mf. *"J Xi-r*. Jrturnnl, 3ft, )Rg. f t.'HKNFF.lI), R., rrf*ool rommnnirMion. |v( HART. T. D'AKC'Y, nH ASI.ITIT. E. A. (ig*i), Spf-ril nrpmt Sr,ir. M.K.C;. No. t\) <). JENKINS, I'. |(. (>o^S), * Mnliro. Minin* A*|>rrlt of Pnciimn- rmiiMii in Sotiii> rirt kkI hrfnrr thr S*Mh \VI ln*inulf of E.rtRin^crft. KF.A't't NfJ. N.. IVnm*wl cwnmnnif^ion. i.r.ri.r.nnj. j.. nAi.oAiRir.s. e. iionie, g., nd I ll-'.f.1 .KIU.'IJ, (. (mmS), /low Atrthrnir Atinirr*, 4, *3. MrCANN. HURTADO, KAI.TRKIDER r*l FRAY (19.17). ymirn. t'lm. 1J. MI' lKI.I'.jnilN', A. (t9|0l, f.nnrrt, t, ^9, ' ("<nliiliitinn nf lli liHpliipiHiil lo Oiniral lUllIt'.IIS, l-NII) (m)mI, I'nprr rr<l Itrfnrr ihf Y*il*prrtil /\tnCItK0. Kt'IIIN, 1.1.1 II. (mm7). * iwl ( o. *f llf Ch*l,' \Y. II. Smimlrr# TATtYHSAl.l.. N. .7. 1 f.hn. )iy,irnt, S, 4(,h. THOMAS, R. \y., I'cMmnil com>nnnirlion. ^, . ASBFSTOSIS Uy H. Wvtrs, M.A., M.D., D.I.II. I: 11 *! Although certain difltcultics remain lo he ex plained, the theory that silica ii a causative agent Sn pulmonary fihrnsis Is wulely accepted. When, Jvnvrvcr, the fihrogcnic potcniialilics of silicates Vr considered, these difficulties arc very greatly Increased. Olivine, for example, has been shown So provoke only a foreign hodv reaction and has i>rrn suggested for foundr) work, whereas kshrstns is notorious. Studies in minernlogiral piinposition of atmospheric dusts and ashed lung Sissue aic progressing and tr the data found Shrorics of soluhilily and crystal form are being Ipplird. If the solubility is high, as in the ease of jilicic acid gels and sols, the material is eliminated loo fast to produce fibrosis. A low solubility, such T* in mixtures of quartz and n minimum, equally retards fihrnsis (King, 1938). ' 'here appears also he an optimum size nf particle with a surface Itca which will release silica in %uff\cirnt quantity Upr a sufftrirnt length nf time. T In animal experiments this was found to he innut o.t micron (Tebbens et oL, 1945). fn the Ease of asbestos fibres, it has been shown that .. I' whereas there is an excess nf chrysotilc over Jiorn* blende varieties in d usts, ashed lung tissues con tain only hornblende (Sumlius, 1938; Kulm, 1941). It is concluded that it is the chrysntile ift solution which is the fibrosing agent. Gardner (193.8) demonstrated by animal experiments that longer fibres produced a fibrntic reaction which did not occur with shorter fibres and concluded that asbestnsis is, at any rate in part, a mechanic ally conditioned complex of lung changes. Fn support of this mechanical theory, Johnstone (1948) records the clinical observation that workers at the Thetford Mills, exposed to high concentra tions of extremely fine: asbestos dust, did not suffer from nsbestosis. ,` 1 ' * ' ^' Structurally silica shows continuous three dimensional arrangements of Si04 tetrahedra and to these may be related such a surface as to pro duce the characteristic biological effects. Those silicates, therefore, which most nearly resemble quartz in having a three-dimensional network of silicon-oxygen tetrahedra are likely, theoretically'* to produce similar biological phenomena. These 6u / POSTGRADUATE MEDICAL JOURNAL , Dccembrr 1949 i' % > arc grouped in diminishing order of similarity by Nagnrhehmidt (1949) ns alkali feldspars, sheet Structures such as micas and kaolin, double and single chain structures like arnphibnlcs and pyrn\rnrs and, finally, the orthnsilicatcs such as olivine. Animal experiments tend to confirm tins, but it is pointed out that (he type of binding of the silicon-oxygen tetrahedm is of biological im portance and aluminium silicates, such as scricite and kaolin, arc not likely to present a major silicosis hazard, t The diagnosis of pathological states of the lungs, due tn dusts, also presents many clinical and radiological difficulties. A high incidence of pul monary disease among those exposed to pure silica is presumptive evidence of ;m etiological re lationship, but the rare ease of talc pneurno- rnninsis is difficult to establish High atomic weights and consequent radio-opacity produce shadows on the X-ray film from inhaled dusts which arc not necessarily pathological, as, for example, in the sidcrosis of arc welders (I)oig and McLaughlin, 1936). Asbestos, its History, Uses and Mineralogy Whatever doubts there may be as to the fihro- grnic potentialities of many silicates, the pro cessing nf asbestos unquestionably exposes tire ^vruTrr to the risk of lung disease. It has been used on a small scale since very early times, bring known tn the Greeks as o nifterr* rx, signifying un quenchable. I Tsed as a substantive, ti was nnsbikee! lime, whilst the' masculine gender, A *fofltrr?o was used to denote asbestos. The word nofloTTovr u which in modern English speech signifies the disease ashestosis, was to the Greeks a plastering nr stuccoing. This last word was nrig nnlfy suggested by Cooke (1924) when he also diew attention to a passage in Herodotus dre/ rjbing a cremation cloth made of asbestos. Tb< Homans knew it under the name of amianthus, a word of Greek origin signifying absence of miasma or pollution. 'They obtained it from the Italian Alps and the Ural. It seemed appropriate that the Vestal Virgins, guard arts of the Sacred Fire, symbol of the deepest emotions and instincts in Homan family life, the last rite of paganism to he extinguished, should have used nsl>cstos lamp wicks. Another fibrous mineral resembling Italian amianthus was spun and woven into a cloth in Siberia during the 13th century. A factory for the manufacture if asbestos articles was opened in Russia in 1760. The rc-discovcry of asbestos in 3876 contributed greatly to modern industrial expansion. * . Today asbestos is used for a wide variety of purposes. Textiles enter into the manufacture of fire-fighting suits, safety curtains and boiler' mattresses. Asbestos enters into the* com position of fagging material for steam pipes, jointing for steam pipes, panelling of rooms, tiles, the lining of chemical pans, the coating of bulk heads of ships and marine piers and perhaps most significantly into the brake linings and clutch rings of motor cars. ' The properties which commend asbestos to modern industrialists arc its resistance to heat, acids, electricity and sea water and its fibrous structure which enables it to be spun. Unlike vegetable fibre, it can be split in a longitudinal direction to microscopic size without discovering an ultimate element and without loss nf identity. The shortest fibre recorded is Grand Canon chrysolite and is nf the order of 0.00075 mm. in length, whilst the longest is exhibited in the Marit/.burg Museum and is 4 3 in. in length. This latter fibre came from Umsinga, Natal, and is also probably cbrysolilr. The best length of fibre for spinning is in. (.1-75 cm)* The asbcstifnriu minerals form a group of silicates which differ widely in chemical com position, but resemble* each other in being fibrous and in their resistance to heat, acids and sen water. Legally ` asbestos means any* fibrous silicate mineral, and any admixture containing any such mineral, whether crmlr, crushed or opened * (Asbestos Industry Regulations,^ 1931). Min eralogists classify I hern ns folbpvs:-- t. Serpentine Group, 2lT,(* jlMfiO, *Si()f. Characterized by a high percentage pf magnesia and water, generally white in colour, naturally lubricant and therefore Suitable for stuffing boxes and glands. Examples, chrysotilc, pirrolite. 2. Rhombic Amphiboles, (MgEr)O, SiOt. Soda confers a brown colour when present. Like the third group the members of this division contain high percentages of ferric oxide and have a low water content. The texture is harsh and elastic, enclosing a maximum amount of air in a minimum of incombustible matter. They are particular!) efficient as heat insulators. Examples, anllmphyhitc, amositc. 3. Monoclinic Amphiboles. Tremotite, Ca(>. 3MgO,4 4S1O,. Actinnlitc, CaO, 3(MgEc)(>. 4$iOs. Crocidolitc, NnEc, (SiO,),, he Si()v The presence of soda in this group confers a lavender blue colour (Hall, 1918). I he ferre nxidc content of crocidolitc encourages slag forma lion when it is employed as a wrapping for elec trodes. The countries of origin are cbirlK Canada (white chrysotilc), South Africa (him crocidolitc and the brown anmsitc), Australia and the U.S.S.R. It is found in the banded iron stones, the deposits being classed as cross fibre, slip fibre and mass fibre according to the direction of cleavage relative to the orientation of the vein. te3 \)cnmh< r l`>19 lv949 '1 hulk- ps most clt i mgs WYKRS: /isbcslosis fi.U imip * i| nl rn'ml fibrous and c;i fibrous nine nnv opened ' Mift- 'iP. mnimmi: ttirwlai I ;, ntllli'i -U', ( n* ` MKI;r)C iOv rnnfcis ' 'hr feei ng form ' for cl' i c cli" 1'^ ica (h!u tralia and ded iron* oss film. (1 i rcct ion the von. ^ ,* :,** ?raU| Fie:. i.--Ad>cstc*b bodies in a section of filirnlic lung. Photomicrograph x 400. ^ p* . From the ease sl>n*n*in 1`igj 4. Ft'bnnira! analysis explains some of the varying Guopertirs of the three groups. \ (Innarlinn ('hrv*ntilf niur (.`mei.tolilr AmoMtr MS.fi. :( .. DAIimmin . I rrnr ( Niilc . . Kl\ 1 .. MAIlcUt* j^Wnlrr .. .. Per rrnt. 41 3 2 40 -- M Per rent. so i 35 2 R 4 Trr rent. 17 U 37 r. 1 3 K----------------------------- 100 >00 100 [M nnufncture The mineral is obtained by open mining, akin to quarrying. Outside the mine adit the crude asbestos is reduced in size and pieces nf iron arc Idetached manually (' cobbing *) nr by mechanical means. It is then transported to the factory in paper-lined sacks where it is crushed in a large [edge runner nr a small pan mill, foreign matter fremnved and the fibres opened in a Crighton finachinc. The ancient process of carding follows, by which (hr fibres are made tn lie parallel In a continuous ' slivrr.* f'ssrnlinlly this machine con sists of toothed drums and condenser rollers. 'I'lie derivation of the word ' card ' from the Latin cnrduws, a teasel or thistle, doubtless indicates the means by which this operation was carried nut on other fibres in primitive times. Slivers arc twisted together to form strong yarn on spinning frames, by ring nr flyer, as in other textiles. The material is then plaited into rope or it may hr woven into cloth on the conventional power loom. To the medical observer, perhaps, the loom as a special significance for the weaver's beam has given its name to living !issues. Occupying a horizontal position in modern looms, its historical position was vertical. The Greeks called it mr#t, as they did a ship's mast or indeed anything which \vas; set upright. 'J*bc word came to be applied to the cloth itself and eventually to the histological structure of living organisms. History of Asbestosis :' In 190b the Departmental Committee on Com pensation for Industrial Diseases (1907) heard evidence from various authorities arising out of . Cl1 ' f>.1 l Postgraduate medical journal. ( Den other 1 >!<> AiJ p-r W'' "l :lf ' S3 V. I*IG. 2.-- 1,.U.S.. frm^lr, net. 15. Spinning drpt., five year*. P.M. section of lime showing blur-black |>olvi*nn:i! arms nf nsbcslnsic nntl ihirkrnrd pleura. At the lower pole a squamous carcinoma surrounds an abscess cavity. thr inclusion of certain irdustrinl diseases m the Third Schedule of the Workmen's Compensation Act, 1906. At that enquiry Montague Murray reported the ease of an asbestos worker who had died in the Charing Cross Hospital in 1900 of ' typical fibroid phthisis.' This man, a card room worker aged 34, had stated that nine of his work mates had died round about the age of to. Whilst agreeing that fibroid phthisis was a clinieal entity and specific to certain occupations, the Committee fell they could not recommend its inclusion in the list of diseases under the I bird Schedule owing to difficulties chiefly of cr rtification. Cases of ashcslosis continued to he reported, notably by bahr (tqt4) and by Cook (1924). It was Seiler's ease (1928), however, which seemed to establish an unequivocal relationship between asbestos and pulmonary fibrosis and which precipitated the inquiry leading to the Report of Mcrcwetlur and Price (1930). In the following year appeared tlie Silicosis arid Ashestosis (Medical Arrange ments) Scheme (1931), the Asbestos Jndusin (Asbestnsis) Scheme (1931) and the Asbesto Industry Regulations (193r). The first dealt wit! the constitution and functions of a Mrdira Hoard, the second with the award oT compcnsatini and the third wilh the control of dust. I^cgislatioi has been gem rally effective in controlling th* disease. --------- - Since 1931 all entrants to dusty department have been medically examined initially and again annually by panels of experts. Use has been mad of radiology and much pathological material examined. Du:;t exhaustion has rereived special attention ; in one factory spinning frames arc being totally enclosed in perspex with an ingenious rust! dt e it I K ti V ]i| 11! <to ,h pi Hfitl til rw> at >to>41 tr t. cr into.'l \sK III :|p,| tn rn ! ca inntl si L pi issaVl so cinq pi Irif 1 as rslril 111 nltJf f, etc (ojin ar. I ll* I pi sene I as c*lTMt co.ntrx* I 'U> ir'vcl Inpprni Ai r.m> lndux< Asbest Icalt v Mc'if prpsat cgislati lling t >:n l tnr-i m<! ng:t rrn mm materi al spccD. arc He in.; ingenious Dnrmhrr *949 WYHH$: Ashnlnsis ' ft'",* hi , device which permits easy access to bobbins. Handling has been reduced to a minimum and . good housekeeping kept on a high standard. With ; very few exceptions, eases certified by the Hoard as ashestosis have industrial histories extending to ,, periods prior to 1931. , Pathology . * Whereas the heavier and smaller particles of silica find their way to the alveoli and thence to the lymphatic channels, the lighter ami larger particles of asbestos block up the finer bronchioles. C hains of silicate tetrahedra with intervening cations determine the fibrous structure of asbestos and these chains in frayed bundles interlock anti arc arrested, lienee silicosis is a fibrosis of the lymph nodes and ashestosis a fibous cuffing of the bronchioles. Dangerous fibres measure about 20 nicrons and a noxious concentration is said to r when the dust count exceeds five million articles per cubic foot of air (Page, 1937). 'There is no local necrosis rr leucocytic reaction o the trapped fihre such as would occur if a irolnplasmic poison like colloidal silica hydroxide vrrr liberated. It seems significant that if the jhmus character of chrysntilr asbestos i? absent, Sjs in its chemical equivalent serpentine, the dust inert. Instead, the lining epithelial cells arc rscpiammated as a result or friction and make [iUempts to engulf fibres which proving ton long, ire sometimes observed prrjccting from these dust ' cells. Ashestosis giant cells arc also seen, iuc to small aggregations of dust cells. They are igmented, stippled and multimiclcar. Fibrodasts appear around bronchioles and alveoli, in Enlcrlnbuiar septa anti in the subpicural connective ,, issue. Ashestosis bodies and pigment are also resent. Finally there is an invasion by collagenous ibres to form the characteristic reticular pattern ijnuml the distal arborisations of the bronchia! ree. The alveoli, capillaries and venules arc Irushed bv the fibrosis. Ashestosis bodies can be demonstrated in the mgs, pleura and sputum. The length of time aken for them to develop is unknown. They annot be found in the mineral itself. It has been '"*vn by staining reactions with sodium nitroTuxsidc and ammonium .sulphide and by disidving th6 outer portion with enneentrated sulhnric arid that they consist of a central fibre of ibrstos (Fig. 1) with an iron-containing, seg mented covering which is thought to have been eposited by a colloidal reaction between the fibre nd the blood proteins (Gloync, *929). Their rrsrnce is eld to be evidence of exposure to ibrstos and not of the disease itself. Dense, sessile adhesions of the pleura arc minion and the interlobar fissure obliterated. The pleura has a ground glass appearance with yellow, horn-like plaques 2 or 3 m. In diameter besides patches of recent pleurisy. The cut surface of the lung exhibits the typical blue-black poly gonal areas, roughly lobular in distribution, J in. to J in. (3 mm. to 6 mm.) in diameter on a red background of bronchopneumonia. The nrens tend to confluence at the bases ami exhibit the ' pleural drift ' common to the pneumoconioses. Confluence is becoming rarer as the dust cloud becomes less concentrated (Fig. 2). Compensa tory emphysema, on the other hand, seems to be occurring more frequently ns cases live burger. It occurs chiefly along the margins of the lungs, sometimes giving rise to bullae but not so commonly as in silucnsis. One ease in the present series of 115 fatal cases died of a spontaneous pneumothorax consequent on rupture of such a bulla. The right heart is generally enlarged ami there arc the usual signs of back pressure in the liver. * Clinical Syndrome In the writer's scries the average exposure for males was ifi.2 years, for females 73^'cars and for all eases to.4 years, The duration of the disease was 6.4 years for both sexes. The mean Age at death was 46.5 years in thc,*e&se of men, 37.5 years in the case of womcr^qd 40.8 years for all , y 4 |1 ' : . ' f '*' 1 * % F? *^WIi r -A > m#m*' , , "H y'.'V- v, `.A- utfl r Fie. 3.--J.N., malr, act. 45. Sectional dept., iR years, X-ray of limp shnwinR Hnr molding. Fingers show gross clubbing. Advanced nsbrstosi*. , e,.- -j / I f 6j6 i lOSTGUADUATK MKDICAI, JOURNAL Drrcmhrr 1940 ^ i .*. eases. Dyspnoea is a universal complaint: burton Wood regarded asbestosis as a mono- symptomatic disease. Dry cough is noticeable on rising in the morning and during changes of temperature. A paroxysm usually terminates with the production of some thick mucoid sputum, very rarely flecked with blond and in the later stages containing mimmulcs of pus. An increase in the quantity of sputum indicates n complicating factor. rz. $ Anorexia, loss of weight, fatigue ami chest pains are occasional symptoms. The cardiovascular signs of I ic disease arc im portant, because once established they arc per m manent, whereas adventitious sounds in the chest tend to he evanescent. An earthy cyanosis has been described. Of 53 comcrutivc cases of asheslosis examined by the writer, 29 showed clubbing of the fingers, the tors being similarly affected in right of the cases, an incidence of 54-7 Pvr cent. In the same series the second pulmonic sound was found to he accentuated in 33 patients, that is to say ft2.2 per cent, of the cases. These signs appeared separately, together aod quite ohm not al nil even in advanced disease. 'The liver was never palpable in an ambulatory patient nor was there oedema of the dependent parts. . 'The rhrst is flattened bilaterally. 'The respira tory excursion rarely exceeds 1 in. (2.5 cm.). Percussion often reveals a sensa ion of resistance to the finger f felting ') which may be general or localized. Probably this is a reflection of the Tin. T.McK., rl .15. KrrM*nn!*Uept., 1 R vrr. AhrMoM* slmwn in t ig. ^ X-ray of lone *hmv< cor>r*r filuocis nnd rjUphx firms rlofthin^ of fmirrs. KventiUU died with Uihvr- cuIons infection. ' V dense character of the fihrotit lung or of the pleural plaques which arc often seen post mortem. I (yper-rcsonnnee is occasionally noted. Dry, crackling sounds can generally he heard along the emphysematous margins hut oft:n become gen eralized or disappear altogether in the same diminished. The cnslo-phrenic sulcus is fre quently blunted. A shaggy left cardiac border is often seen in advanced cases and sometimes thr entire silhouette and diaphragmatic cupolac an blurred. individual. An odd sonorous rhonclms may he heard. 'There is deficient air ertry at the bases and expiration over the anterior aspect of the chest is harsh. Complications Hrnnchicctnsis has been staled to occur fre querdly. Only three undoubted eases occurred ii the present series and one of these was a con Radiological Appearances genital condition affecting the apex. ^rcgnancy was associated with the deaths 1 ' Whereas the roentgenogram may show con siderable involvement in silicosis with fexv, if any, symptoms, the reverse is apt to he found in two women suffering from ashestosis. 'The disen' does not seem to be adversely affected by prey nancy, but the strain of labour may tip the balnn asbestosis ' (Sayers, 1938). This s the opinion of nil with experience of the disease. The typical in favour of right heart failure, ^'monchopncumonia is almost invariably four./ appearance of the lung fields is a diffuse haze or pin-point mottling in the lower halves or twothirds (Fig. 3). Emphysema may he seen in the upper zones and, of later years, a granular pattern in the lower zones somewhat resembling cotton wool which has been teased out (Fig. 4). The domes of the diaphragm are flattened and may sho w coarse slriac running up into (lie lower lung fields. The vertical diameter cf the chest is post mortem. 'The next commonest complicatin' is tuberculosis with a much lower incidence tha ; in silicosis and affecting a lower age group, hi 115 fatal eases, 15 men and 21 women, 31.3 pi 1 cent, in all, showed also pulmonary tuberculosis 'The mean age at death was 34.9 years after an average exposure to asbestos of y.(\ years. Taking the remaining eases alone, the age at death was 43.6 years, after an exposure of ir.5 years. ,J Sot ic^ ii it 11 factors 1 familim ociupath the p*d till** rewk hal it of I winch thr| has imlir losis an j.c>r I'isaW nee tpati*] dying of I clo*-' thfj isan.:- bm isbi sir*. !'nst-<n did' refill ;icri* s iuh 1 .doubt mK Sytuplorrul ,time hirt-'" Of the  H \ f sn v \ nl lurn.' . c;r..v- tH mi>i i * ' . sK.e i ; [[ I >,v - . i . ectiuber 1949 ' tyil1,WYEftS; Asbplotit. /; 1*C. Hi An excess mortality from crmcer of the lung in ,,scs of asbestosis wax recorded by Mercwcther 1)947). Of 6,884 cases of silicosis 1.32 per cent, ere found to be complicated hy pulmonary cancer hcreas the incidence was 13.2 per cent, in 235 ses of asbestosis. Wedlcr 11943) collected 92^ >s(-mortcm reports of asbestosis eases from ifTerent parts of the world and ' found an inidcnce of 16 per cent, pulmonary cancers. The cvelopment of the lesion corresponded with the tngths and intensity of the exposure (12 to 42 ears). Tlocmke (1947) called attention to the tsociation of asbestosis with pulmonary cancer, le latter almost always taking the form of car noma of the pavement epithelium. lie thought possible that, in addition to chemical processes, e purely mechanical effect!; of the asbestos ecdlcs may also be responsible for the develop^ ent of carcinoma. In the present series of 115 deaths from bestnsis 11 males and six fcmrles had pulmonary necr whilst cancer of other organs was present three males and four females (pancreas, colon, oniach, ovary). The proporlion of pulmonary neers in the series was therefore 14.8 per cent, piammis cancers Were present in nine cases, oat II in five, columnar cell in one, endothelioma t^f .pleura in one and the histology unknown in e. Twh of the cases were brothers. The mean e at death was 52 years, the mean exposure to iheslos dust 17.3 years and they died a mean Criml of 6.6 years after leaving the industry t ' I-" s cio-Medical Aspects of Astestosls g; It difficult to assess the effects of such fetors as personal habits and the preference of milics and those of defective physique for certain rciipatinn'S. Mriklcjohn (1929) has pointed out )r possible effects in the past nn the spread nf thercnlosis among Sheffield knife grinders by the shit nf spitting into the water trough through hicli the abrasive wheel passed. Stewart (1929) is indicated that the high incidence of tubcrcu- sis among boot operatives is Hue to the attraction ' disabled persons and their fimilics to a light ;cnpation. Similarly the family histories of those , ling of asbestosis and tubercle frequently dis- Jise the presence of tuberculosis in those of the ' me household who have never been exposed to bestos. Tost-employmcnt survival showed a sex fferentiation; the mean period for men in this fries was 2.3 years and for women 9.8 years. No ylibt many women ceased work to marry and hnptoms of asbestosis did not appear until some Jnc later. " ' t i [Of the 115 deaths only two had commenced work subsequent to the 1931 Rrgniaamna. mkn alter fen years' exposure annHd a woman whl o also had tuberculosis after two years' exposure, 'three other men have also developed the disease after exposures of five, four and four years respectively, the last one having been certified in 1946. 1 The writer has 2B eases under observation at present. The men arc occupied as follows: business executive, storekeeper, painter and window cleaner, lagger (in other employ), cleaning brasses, ventilation engineer, in charge of sports and social sections, laboratory handyman, retired,/ small printing press operator, foreman in charge nf stores, foreman in charge nf robber department/ light carpenter, tally clerk (week-end relief! handyman in canteen, at home recovering fron . tuberculosis and one relief gateman. The womc i are occupied as follows: light housework, i 1 charge of works solarium, canteen work, repairiri ; overalls in works laundry, three doing light house , work and two doing sewing duties and mendin| \ duties at home. A\ The reduction in the intensity of the dust cloud' srems to be producing a more chronic type of disease. Mcrcwclhcl's investigation nf >929 In dicated a period nf seven years' exposure fof the' disease to develop, whereas thij, series, which commenced in 1931, indicates t(i|f an exposure, of ten years is necessary. 7 ' ` ' ' 1 Through the kindness Tit Dr. ^Roodhoust Gloyne, the writer had access to mfe late Dr. Hurton Wood's notcii nn 89 cases of asbestosis which he had collected up to 1931. . Of these cases s. 17 showed clubbing of the finger!!, I.i. r9-t per cent., a much lower figure than the incidence of " ' 54.7 per cent, in this series. Radiologicdlly, the fine mottling is giving place to a coarser shadolving which seems to be due to compensatory emphysema. At post mortem, confluence nf the characteristic lesion is becoming rarer and cancer' incidence is rising. . . .'' > Ai - .E) < I . |. Other Silicates '1 j Of the other silicates, talc is the only one con-'' corning which there is definite evidence of a' harmful effect on the lungs, although there is some.' ' clinical and radiological evidence of pulmonary1 fibrosis due to mica. McLaughlin et nl. (1949)' reported the first ease of talc pneumoconiosis,! confirmed at post mortem, to have occurred in this country. The radiographs showed nodular, shadows which, on the left side were fluffy.* Histologically the lung showed greyish nodules of: loosely woven fibrous tissue in association with' bronchioles. There were also 'curious bodies '! closely resembling asbestosis bodies. Mincralogicalj investigation proved that the condition was not,;' in fact, asbestosis but due _to_ talc, 4a hydrated'. ' 'YVl'. (Vi:Vi . ' A-fiY !': /' 6j8 POSTGRADUATE MEDICAL JOURNAL Dectmber 1949 magnesium silicate Mg,Si40,0(OH1). Talc may in certain instances arise as an alteration product of tremolite and it may replace anthophyllitc, in both cases inheriting an imperfectly fibrous form. Norwegian and Canadian talc* are platy but contain a proportion of fibres. The respiratory passages appeared to have acted as a filter allowing the fibres to get into the lungs whilst rejecting the plates. The authors concluded that talc pneumo coniosis may be ascribed primarily to the physical form (acicular crystals) of the mineral, but that asbestos is more actively fihrogcnic. mnuoonAriiY. ASnrSTOS INDUSTRY (ASnKTOSIS) SCIIF.MF, H.M. Stationery Off*et. ASBESTOS INDUSTRY REGULATIONS {1931), H.M. 1 Stationery Offiet. . BOF.MKE, F. (194?). Mtd. Mimahtcfir., I, a-6. _* HOF.MKE, F. (194?). CArm. Zrolr., |, 833. *` COOKE. W. E. (1914), ffrtf. AW. J., 1, 147. DEPARTMENTAL COMMITTEE ON COMPENSATION . FOR INDUSTRIAL DISEASES (1907). Mitmin of AWdrnrr, Cd. 349*, p. ta?, H.M. Rmiwtrrr OIrw. ` DOIC, A. T,, and McLAUOIILIN, A. I. G. (1936), t, 771. . . FAUR. T. (1914), 1 AKtIi.rtumocOTmw1' MwwA. AW. . KVA., Ii, fti). GARDNER, U U. (>93*),.7. Amir. ftrd. Au., *, 1. GI.OYNE, S. R. (1910). Tuherrte, in, 404. . HALL, A. L.. * Aahrsina in ihe Union of S. Africa,* firologirat Survey, Afmsmr A/n. it, I q 18. JOHNSTONE, R. T. (t94X), Otnifn'ionn! AfrrftVmr tmA Industrial flygirnt, p. 369. KING, F.. J., and ROMAN, W. {193D, RVArm. J., 3a, *t8j. KUHN, J. (1941), Arckf. Gmrrhrpat.i. and Gncrrhehyg, 10, 473. ' McIAllGHLIN. A. t. C.. ROGERS. F... and DUNHAM. K. C. (1949), * Tak rMiimnconimii,' /Irif. J. lodustr. Atfd., 6, 184. MEIKLEJOHN. A. (19*9). M.D. Thesis, Glatgon. MERF.WFTIIEIL E. U. A. <*947). Am,*t Report of thr Chief /aifurlrr of Fnrlnrn 1, H.M. Stationery Offset. MERF.WETHER. E. R. A., ami PRICE C. W. (1930). tlrfm n, Effrttt of Atheito* /Vsf on lAr /,unfi, H.M, Siiliotirry Offrcr. NACJDEIJ*(*HMIDT, G. {949). RrsntrcA. *, 179. PACFK. R. T.. ami IILDOMKIELD. J. J. <937). V.S. Pub. Ibolth Rrpn., 5, 1713. * SAYERS, R. R., nml IAN7A, A. J. (1938), Silirotit ood p. ho. SEILER (ttaft), Hra`l. AFrd. J., it, 981. SILICOSIS AND ASIIBSTOSIR (MEDICAL ARRANGE. MF.NTS) SCHEME (19.lt). H.M. Stationery Office. STEWART, A., rf /. (9*9). Rrtf. AW. J., 1, 9*6. SDNDIUS, N.. and I1YGDEN, A. (1938). 7. M. Hyg. Tv.. jn, 35 TF.nnr.Ns, n. n., scmiulz. r. z., and drinker, r. (19451. .7. tod. Hyg. Tor., H7. t99- WEDI.ER, II. W. (1943). ' Ashoiwr tmd l^mrrnlirrhs,' Dci. AW. IIWA.Aub- h. 99, No. 31/31, 575*6. y 1---------------------------- ;------------------------------------------------ :--------------------------------fi--------- -------------- , THE ROYAL MI5IIICAL FOUNDATION -' of Epsom College ' W tpptil to *ll member* ol (He medltil profession who do not lre<ly do *0, to subscribe to i;he above Royal Medical Foundation. In every profession some mutt It'll by (He wayside; others must inevitably fall upon evil day*. * * , 'V! Our object la to kelp the fam-lie* ol thote less fortunate brethren. To that end the Foundation in 1948 has provided t (a) JO ordinary penalona to meilical men or their widows ... ... ... ' ... ... ... ... ... ... |,$00 (A) 45 Foundation Scholarship* 'or boya--educated, tloth^d and maintained entirely free of cost *................. ... ' .., 1,703 (c) 13 Scholarship* for ylrla ............................... ,............................................................................................................................ . ... 570 (tf) Education of 38 boy* at reduced feet ... ... ... ... ... ... ... ... ... ... ... ... 1,988 (a) 140 pension! and annultle* t'f varying amount* t (f) Grant* toward* education of S( boy* and |irIt (f) Grants to medical men, widow* and ipinaten ... ... ... ... ................. ... ... I... ... ... ... ... ... ... ... ........................................................ .... ... ... ... ................. ... ................. ... ... * ... 3.033 1,843 477 ' ' '* ^ ` Thl* is an expenditure of {18,103 In the year. , (` ^ ' ^ ' In order to maintain this assistance we have to rely upon the fenerosity of our aubseribera and donor* for over i 4,500 per annum. J ** s ., Without tuffident help from them even otrr eeiitinf benafactioni would have *0 be curtailed. Owlnj to lack of fundi, many deierv. *' ' ln| applicant*--medical men, widow* and children of arhool aye--remain onaatiated. The Sherman Bijy Fund enables tha Foun* t ' dation te maka educational (rant! lor thote who cannot obtain Scholarahipt. Donations to auyment the income of thia Fund will ba moat waleoma. y.*,. *, * . " |V * . 1 . .*? . Wa therelora ba| you etrneily to tend either a subscription or a donation te thit Foundation during 1949. When doing 10 you may, II you with, stipulate the particular form of benelaetion on which ft Is to ba expended. ' , . . , .; i Subscriptions end donations may be tent te any of u, or preferably to the Secretary, the Secretlry'i Office, Epsom Collett, Surrey, 1 w. by whom Kill Information will (ladly ba aent on request. -'i-r::: : I* . '' vn ! :l* ; . JOHN SEU COTMAN, Treasurer i` HAROLD SFITTA. Cholrmen ' ' ERNEST GOODHAAT, Ylct-Chehmoft tl'. ............................................................................ . '.-I ' :-T9 ilcnip recently little mors j last df "I'prcriiiia^jj siilcrahl;, J rmiiini, rf j been 'Jt< been inr_ (liseaivM rf| article h n ` stunrtliiry^ briefly they ciun.,4 been eh . fur fmihtfj ilnntn. Mintrslj 1'itntmn Ai(firiu|t'| ini|>rlin( i th-rr in i Manrrfi nmiiitu minernki K; prr'.i nl.'J whet her aci'mofd is often m is s > nr 1 all. cwf | : pu. vinf I t which either bjJ aih.iixtJ | > inluilatlt SlIJCMl tin only) 1 silu atel Mi reirct In the irJ frnm It I further Minnthi I anres i"1 wire 1 Allliotijll