Document ZJy3R8kwjk7MeyM5wDLm6NpbZ

UNITED STATES TREASURY DEPARTMENT PUBLIC HEALTH REPORTS UbUSU WEEKLY BY THE UNITED STATES PUBLIC HEALTH SERVICE Volume 50 Number 1 - JANUARY 4 - - - 1935 J --= IN THIS ISSUE "! ~ - Effect of Asbestos Dost on the Longs of Asbestos Workers \J The Occurrence and Control of Endemic Typhus in AlabamaThe Prison Educator's Viewpoint of Psychiatric Services Deaths in LargeCities During the Week Ended December 15 Current State and City Reports of Communicable Diseases Quanntmmble and Other Diseases in Foreign Countries 1 I 1 mam STARS oovnmczMT numwa omci WASSXMOTOXilMS 0085 '-N.. \ V\ PUBLIC HEALTH REPORTS VOL. SO * JANUARY 4, 193S NO. t EFFECTS OF TOE INHALATION OF ASBESTOS DUST ON TIIE LUNGS OF ASBESTOS WORKERS A Preliminary Study By A. J. Lahm, Auiotont Medical Director, William J. McCowwelj, Attiidnal Medical Director, and J. Wir.UAK Fxiinrl, CXemul, Metropolitan Lift /ruuranee Co. INTnODUCTtON \N , Jn 1020 tho Metropolitan Lifo Insurance Co. was approached by officials representing the asbestos industry in tho United States, who were desirous of ascertaining whether asbestos dust was an occupa tional hazard in their establishments and, if so, what was tho naturo of this hazard and what should bo done to provent or control it. About this time sovoral articles had appeared in English medical journals describing a pneumoconiosis duo to asbestos dust. While in one or two isolated instances tho occurrence of this type of pneumo coniosis had been described in American journals, the industry itself appeared to* be quite uninformed of the existence of any such occupational disease. T1m hazard of silica dint, with special reference to the lungs, has long been appreciated, and a great deal of study And research has boon applied to the problem Cut the metal mining and certain other industries) in Great Britain, the United States, the British Do minions, and in other countries. Hu nature of the effects of silica dust expressed in the term "silicosis", with the resultant extraor dinary predisposition to pulmonary tuberculosis, is wdT known. Tlicso effects have boon associated with llio inhalation of dust con taining freo silica in varying amounts. The effects upon the pul monary tissue of dusts containing combined silica--silicates--are still a fertile field for investigation, but ovidonco is accumulating that certain of these dusts produce pathological results quite distinct from truo silicosis. The name **^bestows." has boon applied to the pneumoconiosis caused by asbestos dust sad it will be so used in this report! Chem ically, the asbestos of commerce is a hydrated magnesium sQicste constating , primarily of silica (combined silica) 44.1 percent, mag nesia 43 percent, and water 12.9 percent, while ferrous iron and nfekalare present in small quantities. This commercial variety of leisea* a- t (i) \ i i i i 0086  * v. V; \ X ' I . '%:' : r3" ' : . V 2 ashestoa most commonly encountered is designated os ehrysotila nnd is one of the four vitriolic* of tho mincml serpentina, in which it usually occurs in seams. It should bo homo in mind that silicosis (nnd presumably nsbestnsis) dovnlops Tory slowly, taking from 5 to 15 and oven 20 or 2.r> years to booomo established. This rnto of progres-i is influenced mainly by the dnsngo of silica which llio lung* receive, nnd Ibis dosngo, in turn, <k|>cnds upon three variables- the nmount of silira in tlio dust, tlio quantity of dust in tlio air, and tho length of exposure. Individual'idiosyncrasy might bo included ns a fourth variable; however, Iittlo is known of tho variations in susceptibility in those exposed to dust It might well bo Assumed that similar variables would influence the occurrence of naheatoxis. In places where asbestos is' mined or fabricated in North America there does not appear to 1 present tho dear-cut clinical picture which is so uncscapable in communities with a true silicosis hazard, such os hard-rock mining communities. It may be that some of the asbestos plants are of too recent origin for the typical effects of a silicate dust to become manifest, but this would not apply to tho older mines or to all of tho fabricating plants. The industrial health service of tho Metropolitan Lifo Insurance Co. undertook the following investigation during tho poriod from a October 1929 to January 1931, which included: 1. A study of dust conditions in asbestos mines and mills in Canada and in fabricating plants along tho Atlantic Seaboard in tho United States. 2. Physical examinations of osbostos workore, including X-my films. 3. A study of dust exhaust systems designod to eliminate asbestos dust. Data on the fabricating plants only are included in this study and art designated in tho report as plants A, B, C, Dt> and E. This is a preliminary report. A more extensive study of the asbestos industry is now under way. DUST STUDIES Apparatus and methods of sampling.--Both the impingor (1) and the electric precipitator (2) were usod for tho collection of air samples for duets at the breathing levels and in dose proximity to the workmen. Both of these forms of apparatus are adapted for this work, as they are transportable, easily eat up and adjusted for the taking of tho air samples at the proper level, and are extremely efficient. The impingor collects the dust by aspirating the air and then impinging it onto a flat surface covered by a Squid in a container. The Squid used was distilled water, containing 50 poreent alcohol to \ 0087 v x <; \ Xv ' 3 7MMMT7 <* IM prevent the solution of some of tho iltra!*, parlirtilorly any nib'ea which mil'll!. 1m present. Tho ini pinker wns arliuilrd hy nn clrclricolly driven rotary pump and the rate of air sampled wns measured by means of s resistanco typo of flow meter with nn inclined mannnioter for measuring. tlio pressure di(Terence. Knrh sntnplo represents the dust collected from a vohnnn of 100 euhie feet of air. The eleetrie. precipitator is designed upon the Cottrell precipitator principle used for recovering dnsls and fume;* eouimerc.inlly. Thin principle depends ok'electrifying (ho dust particles hy milking them puss tlirough an electrostatic field and thus causin'; them to sctllo out upon a sheet of celluloid. Tlio electrostatic field is set up hy means of a transformer operating from the lighting lines on 120 volts, alternating current. Air is drawn through Urn apparatus by a small rolJtry fan, run by a motor, the quantity being mca-jired by a flow meter. . Samples of dust brushed from beams and pipe lines near the ceiling also were secured for ehomieal analysis. All samples were shipped to tlio industrial hygicno laboratory of tho Metropolitan Co., and Uio dust counts wore mado according to tho methods accepted by Uto United States Bureau of Alines and tho United Slates Public Health Scrvieo (1). Particles in stzs up to 360 microns in tho greatest diameter were counted. Chemical analyses were mado for total (free and combined) silica according to the accepted standard method of Hillcbrand (3). In the first plant studied (A) only particles 10 microns and nndor in size were counted. It has been demonstrated repeatedly that no silica particles exceeding 10 microns (a micron equals one-millionth part of a meter or one-thousandth port of a millimeter) in greatest diameter enter the long tissu ; for this reason, tho larger particles usually are not considered when determining dust counts. Later, as it appeared from wmia of the published articles (4) (Rnglmli) that dsImsUm particles much larger in size were found in lung tissue, it wan dccidod to eount all particles and moko differential counts of oil those 10 microns and under.1 Total particles per cubic foot and tho corresponding weight of the dust in milligrams were obtained. Sinco no relationship between tho dust counts and the corresponding weights was found, the weights are not included in the tabulations in this report. . Table 1 shows by plants and by deportments the maximum and minimum dust counts in miQioa particles per cubic foot of air. -Although the counts in plant A are of particles 10 microns and under, .* tamplm alaM W MS to* toipliqto aaS tha iln iru pnrtplttoto wm amntal. U vHMI--, .'ienslBWotsteWttaMtalWrtkkiw'naJtKMbrMacpnWcfadapaamwBwttSakBUn- ~OMiin|HUr,tktakf*rtpHtldaMsi! Maw! vll* tutor. Xawtlw Itolto mknmmt (by MtMl mmsDi Svaaar.ta wtoatoto tk* vtotetl partieto (to* (B. ItltowS tilto (S toarSteto imWMWtmf*, Om lecwttSsM totfc* laacttos to t a--wit Os tU cm Onto ptottoS <l--spptot ISpwlMHtT to nr inn11 m itoetoq ! 1 ! ; j j j 1 j I 0088 ;mi*ry i m 4 itnd in the other plants are for idl particle, clirret eompnrison is possible, os in no saihplo token were tho number of particles 10 microns sad under less tbnn 04 percent of the whole. Tuu l.--Maximum and minimum dual ernuti in million particle* per cubic foot af air, by plant and department FlutA rUat D iw o rtuii) riant T, IfepatraMt VftSb tor of mum> pfci Ukffi MRUm pmJHn tmdrr Wtolwr Mot of Kttm* hunt tun* pirn UUo Mltton OOfll* tWwf eubi m r ilr Vatutor of mo* pint tIk* Ir Milton parti* riM prr eoWa to* of Mr Vom> tor f Bffli pint tetM KumMilton tor a4 FQrlt* MID* or* nr Pto Cllrif t*r toot of mtde if kmiti Mr Million IWlt* rtre tr mid* leant W Mr PrfparMlwfi..,.......... Ciu*| rtwn__________ Ktns fntrot cjiiaidac Mtk r-ftfitaifte......... Twrime.............. Wrwvrit- ................... XrU tlrimrURHit....... HItort liwiUileg____... Mektcri hr-Mk# bawl mt rlntdl............ ff-IH t h-im $ 1 VX IWS r3 t M- M "~*T n < 1r H 6 1 1 t *49 3H-UM *i -i?. I W-W IncluiM la iptaMiac. ' Imcknita bnml km wnrlat 9 si I 3t l 37 9 Whereas the dust in tho preparation room practically all due to asbestos, tlio contrary is the case in tho other deportments. In tho curdins, spinning, and weaving rooms asbestos comprises stout 25 percent of the material usod. On special jobs tho percentsgo of asbestos may be higher, bat is general tho figure quoted is approxi mately correct, tho other material consisting principally of cotton. In the insulating departments of plant A, asbestos is but 5 percent of tho total material used. In tho molded brake-lining and clutch division of plant D, asbestos comprises about 25 percent of the total material The actual exposure to asbestos dust, therefore, is consid erably less than is indicated in tho dust counts in table 1. l cownmoNS in the plants N \ N, s \ s -v X : v \ 'x The proeesnas in these plants were very similar to those in cotton mlH* in general For illustration, the process in tho preparation room of plant B is here detailed at length: Asbestos is received in begs. These are emptied upon the floor and the asbestos is shoveled into pug mills end run for about 5 minutes in-order to crash sod open die fibers. From there the asbestos is shoveled into tracks and wheeled to hoppers with either horizontal or vertical opeaen, similar to thoeonsed in textile miDe. After passing through the opener, the material is discharged into tracks. Waste x manufacturing material is first run through'a garnet madunc sad $ 0089 ?aatmry . IU* discharged into trucks, which nrc wheeled to Iho openers, mid the mstonal is fed into Uiese in' the same manner as is tiie new material. After being discharged from the opener, the material is put onto a vibrating or shaking screen, whero tho long fibers are picked oil by a suction hood and blown into a bin to be used again in textiles. The short fibers falling through the screen ore either sold os such or used in making an asbestos cement. Tho eotton is received in bales, opened, ami also nn tlirough vertical openers. It discharged into trucks. The filled trucks from the vertic.nl anti Imriumtnl openers containing cither the nshestos filter, tlm cotton, or llio wasto matcriul are taken to separate storngn bins. As needed, (item materials are weighed and dumped onto Iho floor in proportion to tho mixture desired, and tho resulting mixed materials are then passed through a mixing picker. As this mixture is discharged from tho picker, it is sprayed with a light mineral a3. Tho material is then token by a mechanical conveyor to tho storaga bin in the card room. Two of theso mixing pickers discharge onto this convoyor system, whilo a third machine in equipped with a suction dorico which convoys tho material to a storage bin in tho card room. The object of tins two systemn is to facilitate the handling of two grades of mntcriol at tho samo timo. Tho third machino is not equipped with an oil spray. Tho object of tho oil spray is pri marily to entrap the small asbestos fibers and hold them enmeshed in tho eotton fiber throughout the processes of cording, spinning, and weaving. Incidentally, it is apparent that it also diminishes tho amount of dust. The material is saturated with about 4 percent of oil at this point; but by tho time it reaches tho looms, the oil had diminished to less than 1 percent. While mineral oil was used in tho preparation room of plant C, it apparently was not as efficacious as in plant B. In plant E oil was not used, nor was there any attempt at humidification or nny system of dust exhausting. Carding machinas were fed by hand. In plant A there was a humidifying, ventilating, and beating system, while plant B depended on natural humidity. In plant E the carding machines were equipped with a dust-exhaust system, but it was not efficiently usod. In plant C carding was done in 2 buildings, 1 of which was equipped with an air-conditioning system, and in both buildings tho machinas had exhaust equipment. ^Two plants, B and C,.had artificial humidity installations in their ffimhifl rooms. In the former the temperature was 78 F., relative tfmmidity 7$ percent. One plant, C, bod a humidification system in - twisting department and also in tho weaving department, when the (dative humidity wot 78 percent with a dry-bulb temperature of 69 7., as compared with a relative humidity of 44 percent in the \ weaving room of plant A. 0090 v\ v \\ s. V '<IW tW4.4 .M-jM lawyi mi 6 Aside from plant E, it wouia. appear that the dust hazard was not excessive except in the preparation rooms of plants B and C. The dust counts aro interesting, too, when considered in the light of tho permissible standard for granite dust, established by the United States Public Health Service (7), namely, about 10 million particles (10-microns and'under) per cubic foot. However, we are not justified in assuming that because available information suggests that uslxvitnsis is a milder discoso clinically than silicosis, tho threshold <>f pcrmiwublo dust counts is highor. Ahbestows appears to bo patho logically difTcrent from silicosis, anil the experience ho far does not warrant an attempt to dcfmo a standard of dustiness for iisliwtoa dust. STTBT COHTBOL Various measures, such as oiling, humidification, and local exhausts, tended to reduce the dust. Nevertheless, it was evident that they were only partly successful. If it is expected to control dustiness in these plants, final reliance must rest upon property constructed exhaust equipment. In plant C in one deportment on experimental installa tion was set up. In spite of some obvious faults, this equipment, on the basis of comparative dust counts, reduced the dust by 50 percent and with further alterations will probably be 75 percent effective. In this case such a reduction seemed quite satisfactory. It is neither practicable nor economically desirable to install such equipment as will make the air entirely dust free. The normal defensive mechanism of the body takes care of a fair amount of atmospheric pollution. It is when the body is exposed to an excessive amount of dust that this dofenso mechanism breaks down. Tho application of exhaust equipment to textile machinery involves considerable difficulty, especially when tho construction of the plant is such that it is not possible to apply down-draft Buctioa to tho looms. It is desirable to install exhaust apparatus in any plant on on ex perimental basis first, and then cheek its efficiency by dust counts. This practice will remit in saving a needless expenditure of money. fhtsicol xxajaxAxroim X-ray films were made of 126 persons (108 men, 18 women) working in asbestos plants in the United States. All but five of these were given physical examination. The cases were selected more or less at random from among those haring more then 3 yean of employ ment in the industry. It was soon obvious that the early diagnosis of ssbestoeis must test to a large extent on X-ray pictures of tiro chest. As in the early stages of silicosis, tho clinical symptoms of V the asbestos workers were usually indefinite and inconclusive. The interpretations of these films are based on tho readings of ono com petent roentgenologist, but they hove been reviewed by several 0091 7 Jimutt i* IMS oilier* experienced in thin field. T1t (linToirnrc* of opinion wore of ft minor nitl-iire, and there wns general agreement nn l interpretation. Thn film* were rend conservatively, taking into arrounl (lie physical cxnminulinn and Umi 'ge of thn individual, noil were dnssed ns positive only when there wna no major disagreement. All examiner*' wore guided hy their oxjiericnrn in silicosis and other tyi>cs of pnetimiHfinifRies. Thn film* clamed ns negntivn for nsl*rslosis were further subdivided into doubtful nnd negative. Only timn run tell whether tho individual* classed its douhtful lire prugn-tsing tnwiird o defiuito nslteslosis, 1'articular attention was focussed on the prrsenro nr nlisenro of indimlions of lultcmilosis, nod in this respect all I ho reviewers of the filnw were in accord. Willi tlio unliappy experience of silicosis in mind, it wna felt tlmt n great deni of rare should ha devoted to nseertaining, if possible, wlwtlier or not nahestosis pre- <lis|K>scs to tuberculous infection. The eases of asbestnsis were divided into two classes, first stage and second stage. Tlio first stage embraces thoso who show hy X-rny examination dclinito lung pathology sufficient in extent to warrant a diagnosis of pneumoconiosis, but who have no definite symptoms. Tho second-stage eases exhibit more extensive lung pathology and also definite symptoms. All these individuals 1 were actively engaged in factory work, and it was not practicable to mako any distinction on the basis of working ability or disability. Had any individuals been found who exhibited extensive pulmonary involvement and marked physical disability or total dioibility, they would have been classified as third stage, hut no such eases wore found. Of tho total of 126 X-ray examinations, 4 were diagnosed as second-degree asbestnsis, 63 as first degree, 36 as doubtful, sad 20 ns negative. There is a definite increase in the percentage diagnosed as positive in relation to tlio yean of exposure, as shown m table 2 Small numbers mako it impossible to determine bow far tho factor of tgo enters into this increase. Tsais Z CTanQrafira ofeata kg ywi tf apotun 'WESM .................. . iMiat OHaMaavtartantlaalM M ISb Mr. M h MSI > taM hft ftiumi pmMm Tmmtm KM. OaartM wiim ............. tr m m 9 or 9ft ' H3 a 9a t| 3 9 a Hart n .. ........ MMSasa N iiMMriaii s Of tho 64 persons given physical examination-and dingnosed ns having pomtivo asbcslosR, only 8 were entirely free from symptoms, while 10 out of 37 with doubtful and 7 out of 20 with negntivo dine* noses wore free from symptoms. Dyspnoea and rough were tlm symptoms most complained of, but none of these rases exhibited the urgent or evident ty|e of "short wind " seen in true, silicosis. Severn! of llmso classed ah'negative stated that they were "short winded" and we.ro so recorded, blit too much emphasis should not ho placed on statement* of suhjecUvn symptoms. During the progress of the Study, physicians who were prnc.Ue.ing in the communities wlmro nslmslos woritem livod were questioned mm! stated that they did not find on unusual amount of taimrr.ulosM among these workers. Tim contrast between this state of nfTnirs and that found in a community with a silicons hazard is noteworthy. Tim incidence of tuberculosis (based upon X-rny films) is given in table 3; 40 of the 67 examined had less titan 15 years of employ ment in the industry. Tabls 3.--/Kcidmrx of tubereulant rartttM IXbMM NvcmUr, Tt TahwtuMwU (mUtO............... --................... ...........-------- tl 0 a i t a i TMicyawiHn--11 pnfeaMr arUv*M tfc X**y SwUnca Table 4 gives information as to physical signs of chest troublo. Tasls 4.--GUat Jladtss* rwntn DqibtfM KWH* Mt--*iw&:................... '<im1Aot(lUiwmmmm mHtlMt--nmcSutwaSw*wlI--UirarahatiMeawawttMn*BI*niimmdAst wwoUahhwMH, SIiMntafMUafa. >a a i a l| a2 a 1T* ft a What significance, if any, can be attached to the presence of "asbestos eons" on tho hands of workers appears doubtful, as 13 percent el the positives (12 out of 64) and 15 percent of tho others (doubtful, 7 out of 37, negative, 2 out of 20) showod such corns. Each roentgenologist who reviowod the X-ray films collod attention to the fact that those films indicated a very unusual incidence of enlargement of tho heart. It is probable that this is a compensatory enlargement due to the additional work put upon the heart in ofTorts r i i ! ! f i 5 0093 \ ^ \ s' ,\ ' -c 0 to pump through the fibrosed lung*. It is poMtildn Unit, not sufficient attention Ims boon paid to tho cffacls of Clio pneumoconioses upon tins heart. Many workers had changed from one department to another and from ona plant to another during their years of employment in tho asbestos industry. Since only the amounts of dust colioctcd at tho time of this surrey in tho rarious departments are known, thoro is no way of knowing tho avenge amount of dust in tho atmosphere inhaled by these people over the years of their employment. Conse quently, it is not possible to correlate individual coses with definite amounts of dust exposure. XXBUnONCK CLAIMS To throw light on tho relationship between ashcstosbi and pulmo nary tuberculosis, an analysis of death claims and total and ;>ormanent disability claims was made in regard to coctpanics carrying group insurance and having available figures. 'fliere were 2,009 lives involved, with a total exposure of 7,010 lifeyears. Tho death claims are so small in number that reliable con clusions cannot bo ronchod from any subdivision of tho figures. Tho 6<une is true of the sickness claims under health insurnneo. Tho numher of claims for rrspimtory diseases is high in two of tho plants studied hut low for tho others, as compared with the Metropolitan experience of 1927. However, during tho latter part of 1928 and tho first port of 1920 thoro wns an epidemic af influenxa. Tito records of one establishment (plant II) showed that 6 of 30 death claims and 8 of 10 permanent and total disability claims went listed as due to pulmonary tuberculosis. Titis appeared to be an in ordinate amount of tuberculosis from this plant. However, many of the employees were Negroes, and also tuberculosis claims ore gener ally high in this section of the country. Realising the difficulty in diagnosing pneumoconiosis and the tendency to confuse it with tuberculosis, these claims were studied individually. The physicians who had treated the individuals were interviewed, and the hospital and sanatorium records, including available X-ray films, were investigated, with the following results: Dtnlh dnima: 1. A typist, not oxposed to dust; died of pulmonary and intestinal toborealosi*. 2. Colored mate, age 27; worked in asbestos 1 year and 8 months; died of pulmonary tuberculosis following a hemorrhage; ; ^wes in sanatorium 10 months. Also hod a four plus Wssscr\> imann. No evidence of asbestosis. .3. Colored malo, age 32; worked in asbestos plant 1 year and 7 months; died of pulmonary tuberculosis after 1 month in hospital. Cavitation both lungs; no evidence of asbestosis. 0094 n ' .. | \\ 10 4. Colored male, ago 34 j worked in nslicsUw plant 2 yearn ami 0 month*. Ilia physician believes this was a cnsn of uncom plicated tuberculosis. Wn* not inmate of hospital or sanatorium. No information could bo obtained on tho other two eases. Total <tnd permanent dinahility claim*: 1. Main,-employed in aslxxl-os plant 3 years. Ills physirinn Rlnles that hn first came under his observation with nn old cslalvlisiied ruse of tuberculosis about. 2 yenrs after asbestos employ ment started. 'Also bud tul>emilosis of the kidney nnd rervirnl glands. 2. Male, employed in nsliestns plant ft months. His physician HtatcM finding nf old fibroid tiilterrulosis with tulierrle bnrilli in sputum. No X-ray available; but according to pbysirian, as bestos Imdics were found in sputiim. 3. Male, 10 years' employment. Two physicians who treated him nt different limes aro now inclined to lxslicvo this man is not tultcrculoua, but has asbestows. 4. Whito male, was reexamined at lime of investigation. Ills physician reports well nourished, husky looking, good color, no cyanosis; no clubbing of lingers; diminished expansion; ineeswint cough; X-ray shows fine mottling disseminated ihmuglt lxith lungs. No ovideneo of tuiierculosi*. Probably a second sfsgo asbestosis. 5. White male, 13 years in asbestos plant. Is now in sanato rium. As interesting ease. Ilia physician states that he has ex tensive asbestosia and pulmonary tuberculosis; cavity in right lung; sputum boded with tubercle bacilli and asbestos bodies; believes tuberculosis bng antedated ssbestosis. This patient is progressing in a satisfactory manner. It waa not possible to locate tho other throo cases of total and permanent disability who had been diagnosed as having pulmonary tuberculosis. On tho basis of tho information obtained, the deaths in death-claims ease* appear to bo duo to uncomplicated tuberculosis; throo of them were Negroes, who were prnhaidy tuiiorr.iitous at the time their employment in tho asbestos plant commenced.* Of tho 8 disability claim eases, 1 was uncomplicated tuberculosis and 3 ware uncomplicated asbestosia who were put on disability bocause of a mistaken diagnosis of tuberculosis. In this same com munity wa know of one doath duo to uneompGeatod asbestosia in an individual with many years' employment in tho industry,' CONCLUSIONS j-.. 1. Prolonged exposure to asbestos dost caused a pulmonary fibrosis _^. of a typo different from silicosis and demonstrable on X-my films. Clinically, from this study, it appears to be of a typo milder than siBcowa 3. Caaea of dofinito cardiac enlargement were frequently found to be associated with aabestosia. 0095 I \ \ 11 ItaoMTOOf 3. A predisposition to tuhcreulosis duo to asbestos dust was not indicated in (.hi* study. 4. Anlxwtnsin ns observed in this series of eases Had not resulted in marked disability in any case. C. It is not known how much asbestosis may add to tho mortality of pneumonia and acute nontnbcrculoiis pulmonary infoction*. Ci. 11, is not prae.licnblo a* yet to establish standards for Uio asbestos dust eon tent of air. r.' 7. The amount of dust ia tho air in tho asbestos plants studied can bo Buln:tantially reduced. RZCOKMBHDATI0N8 It is recommended-- 1. That the industry seriously faco tho problem of dust control in asbostos plants. 2. That now employees bo oxnminod physically, including X-ray examination of tho chest, and rejected for employment if they show tuberculosis or pneumoconiosis. 3. That employees bo examined physically, preferably every year, but at least overy 2 years, this examination to inciudo an X-ray examination of the chest. 4. That the industry sponsor studies on known eases of asbestosis, as well as studies on effects of asbestosis on the heart and circulation. ACKXOWLBDGMBlfTS Tho authors wish to express their sincere thanks to all those who aided in making this study possible, especially tho officials and em ployees of the asbestos companies wl>o cooperated to tho fullest extent ami gave overy facility for securing data; also to Dr. 1'anroust, of tho University of Pennsylvania, for his interest and valuable advice in interpreting X-ray films, and to Dr. F. V. Meriwether, of the United States Public Health Service, surgeon in charge of Uio United States Bureau of Mines Cooperative Clinic in Piehcr, Okla., whose inter pretation of all the X-ray films listed in this report is followod. Ap preciation is also expressed to Dr. W. Atmar Smith, and Dr. Kenneth Lynch, of Charleston, S. C., for information and advice, particularly ns to the pathology of asbestosis;4 to Dr. W. W. Wild, of Charleston, S. C.; to Dr. Joseph H. Wyatt, of Newark, N. J., and Dr. H. H. Fellows, of New York, for assistin'* in interpreting X-ray films; to Dri pul O. Stroke, of Lancaster, Pa.; to Dr. R. H. Stevenson, of j Danville, Quebec, Canada; and to Dt. L. U. Gardner and Mr. Donald ^ & Cummings, of the Saranac Laboratory, who have undertaken the , study of the pathological effects of the inhalation of ssbostoe dust I < Aihmtmitbmilmt* matam ott tm. 9r bnttU.LracS.M.S-*a4ir. JLtMfMtt.IC.il. I 'Hm.jLa.ittt. in. im aianaan.tw.iset - I Itumrji, its 12 through animal experimentation, with tJio aid of a grant from tho Metropolitan Life Insurance Co. Rsrsii&NCEa 0} Greenburg, Leonard, and Woomfield, J. J.: The (mplnger Hunt sampling ap paratus as used by the United Slates Ihihlie Health Service. I*uh. Health Hep., vol. 47, no. 12, Mar. 18,' 1032. Reprint no. 1538. (Z) Drinker, Philip, and Thornaon, Robert M.: Determination ot atiapenaoida by alternating-current precipitators. Jour. Ind. Hyg* voL VII, no. 0, Juno 1025. (3) Ilillchrand, W. T~ The analysis of silieate and carbonate roekn. ItulL 422, United States Geological Surrey, Washington, D. C. (4) Cooke, W. E.: Pulmonary aabestana. Brit. Med. Jour., Dec. 3, 1027. (5) Green, IL: A photomierogmphic method lor the determination of partiele rise of paint and robber pigments. Jour. Prankfin Institute, 1921, pp. 103,637. (fi) Whipple, G. O; Vital statistica. John WQey and Sons, New York, 1025, p. 451. (7) Runnel, A. E., Rriltea, R. IL, Tliompann, T*. 1L, and IVInemfield, J. J.: The health of workers In dnnty tradea. If. Kxpnnare to siliceous dust fgmnlto Industry). Pub. Health UulL No. 187. 1020. ENDEMIC TYPnDS IN ALABAMA * yt s s 1' oouwicm ocaccs, os is onown m wouri^ inat outer countries nnvo experienced a similar rise in incidence is evidenced by the figures in A /^ |Pn-' of tlna country was first recognized in 1S9R by unu. Me (l) found in the United States a type of fever which, resembling typhoid, gave a negative Widal reaction. In farther studies ho (2,3) demonstrated its simflsrity to^fyphus, but showed that it was milder in diameter and less eonty^oun, only ono esse as a rule being found in a household. Also' he repdefcd that it was most prevalent daring the fall of the year &U.; *. instead, delate winter or spring. In 1012 Anderson and Goldberger (4) nroved that Brill's disease was iminunologicaBy identical with Mtnean typhus, or tabardillo. Naturally this led to the belief that it was louse bona. < *s Ml--fr tmUmm 1 its iwHu PsbSt Bait* t--Ilia, f--rtisa. OUK. 0097