Document jmv32yJrgkgQVQB5p6dLVDvwp

lUOCHBM. IUiS. Lah, lueitiTia) MAY 8 1944 ST 0852437 INTERNATIONAL LfpOUR OCCUPATION and HEALTH Encyciopattfla of Hygfono, Pathology and Social Welfare, Studied from ttm Point of View of Labour, Industry and Trades SPECIAL SUPPLEMENT INDUSTRIAL HEALTH IN WARTIME // o .fj THE DOW CHEMICAL' COMPANY $ T18O0X3 IBCUOILLODGINYGLIBRARY O 25 cents. MONTREAL 1944 QT) 1 shilling. S T 0852U38 Silicosis and Other Pneumoconioses French: Silicose el aulres pneumoconioses. -- German: SUikose und andere Staublungenerkrankungen. -- Italian: Silicosi ed allre pneumocontosi. -- Spanish: Silicosis y, otras neumoconiosis. During the past few years many in silicosis or develops into a silico-tuber- vestigations have been made and inter culosis. esting reports published concerning the occurrence and prevention of silicosis, a disease with characteristic modification of the lungs caused by quartz containing dust. Some of the more important papers, describing the conditions in different countries and different occupations, re late to the Witwatersrand goldmines'; the Schauinsland mines (gneiss quarries) *; the Joachimsthal pitchblende mines*; the "Tri-State district", a zinc and lead mining district in Oklahoma, Missouri and Kansas4; and porphyry quarries.* Several investigations were made among coal miners, especially among soft-coal miners, who inhale coal dust mixed with quartz dust. D'Arcy Hart, A8lett, Hicks, Yates, Belt, and Ferris have published the results of their examination of workers in South Wales coal mines'*, where 560 anthra cite miners were examined in all details; 1,392 bituminous and anthracite miners were examined only by X-rays; and 470 coal trimmers were examined mostly by X-rays. Pathological pulmonary changes The conditions in steel plants were in vestigated by Cummings*; in rock drill ing by Niohmanand Kiessling7; among casting cleaners by Hedenstedt*; and an investigation was also made in the silica brick industry.* A paper on mica and pegmatite work ers, handling material containing quartz, was published by Dreebsen, Dalla-' valle and others.10 could be found by X-rays only in workers who had been employed for more than five years, and these changes were much more frequent in anthracite miners. The authors describe an increase in reticular tissue, different from the fibrosis of sili cosis, caused by the' combined effect of carbon and silica dust. The nodules were generally softer than in silicosis. Flinn, Seiffert and others have studied the situation in three bituminous Very interesting is a "Restudy of a coal mines in the State of Utah.14 The Group of Granite Workers", reported by dust content of the air in these mines Russell." A large number of granite was very high. The quartz content of the workers, first examined in 1924", were dust, however, was not exactly deter re-examined. The re-examination corro mined. Among 507 coal miners, 58 per borated the experience that the develop cent, of whom had been working 10 years ment of silicosis is not stopped by shift or more in the mines, there were 16 cases ing to non-dusty occupations. The pro (3.15 per cent.) of slight anthraco-eili- cess continues towards a more serious cosis, while in a previous examination of 2 ST0852U39 anthracite workers, among 2,711 men, were discussed by the Germans Roem- not lees than 616 (22.7 per cent.) were held, Kempf and Wedler.50 suffering from silicosis; of these, 82 were in the second, or moderate, and 24 in the third, or advanced, stage. An important paper on "The Dust Hazard in Tremolite Talc Mining in cluding Roentgenological Findings in Another study, dealing with the con Talc Workers" was published by Siegel, ditions among non-ferrous metal-mine Ross Smith, and Greenburg.11 The workers in Utah was published later.1* talc of these mines is of the asbestine Among 727 workers examined, 66 cases of variety, mixed with tremolite and an- silicosis (9.1 per cent.) and 42 border-line thophyllite. The content of free silica is cases were found. 1 per cent, or less. Among 221 tremolite Clarke and Moffet examined 774 workers in bituminous coal mines in Massachusetts.1' They found only eight cases of silicotic nodulation: a rock driller who had worked 11 years, an undercutting-machine operator working for 16 years, and five coal-loaders working for 23 to 36 years in the mine, and one worker who had worked in other mines before. talc miners and millers, advanced fibrosis was found in 32 men who had worked for 10 years or longer in these mines. Apart from this fibrosis, which was of a fine diffuse type with a roentgenographic ap pearance of granulation or nodulation, deposits of an opaqu6 material, "talc plaques", were seen roentgenologically in the periphery of the lungs. The men. suffered from dyspnoea, cough and fatigue. The illness had a disabling char The results of the examination of coal acter. miners in the Donetz Basin in the UiS.S.R. were similar to those obtained in South Wales.17 Porro, Patton and Hobbs" exam ined 15 cases of pneumoconiosis, with five post mortem examinations. Talc It must be emphasised that the pneu mining and milling were the obvious moconiosis seen in coal miners is a sili cause of the pneumoconiosis in all these cosis altered by coal dust. cases. The lungs were stiff, showing Grieshahmer1' investigated, by means of experiments with animals, the reaction of the lungs to brown coal (lig nite) dust. This dust caused neither fibrotic nor other permanent changes in the lungs. weakly outlined grayish bands and no dules in the parenchym. The authors point out that "diffuse haziness is the most constantly noted roentgenographic abnormality, and it is probably the earliest change detectable in pneumo coniosis due to talc". There is only one dust, besides quartz, which is commonly known to cause severe lung diseases, but different from silicosis: the dust of asbestos, a magne Gardner" also considers a homogene ous haze as the characteristic pheno menon of X-ray pictures in asbestosis. sium silicate. The effect of free silica is a chemical Interesting work on asbestosis has been done during recent years by the Italian authors Vigllani, Mottura and Fagiano.1* irritation, not a mechanical one. The effect seems to be different in asbestosis. Gardner" writes (p. 316): "Experi mental observations seem to be indi cating that asbestos fibres cause fibrosis Some, clinical aspects of asbestosis in the lungs because they act as mechan- 3 ST 0852440 ical irritants in an organ whose function formed into water containing aluminium involves considerable movement". silicate (clay substance). Thus both Talcs appear to be capable of produ cing a lung disease similar to asbestosis, but with some added silicotic signs. It must be emphasised, however, that no other silicates, except asbestos and talc, aluminium and silica had been made innocuous. This fact, however, has no bearing on the damaging effect of alum inium as such, on which Goralewsxi17 has reported. have been proved to produce serious Joetten1* tries to prove by means of changes in human lungs. animal experiments that there is no true There are many problems- connected with silicosis. One of them is the question how other dusts, inhaled simultaneously with quarts dust, modify the X-ray pic tures and the pathological findings. The antagonism between the inhaled quartz and aluminium, but his experiments are not convincing. Further investigations are necessary to solve this important problem. inhalation of pure quartz (stone-cutters, grinders of sandstone) gives X-ray pic tures and pathological changes different from those found after inhalation of quartz dust mixed with coal dust (coal miners) or with clay (potters), although the principal fibrotic changes of the tissues are always the same. Further in vestigations are, however, necessary to clarify this problem. The question whether silicosis can de velop in the lungs without the co-operation of the tubercule bacillus is settled. There is no longer any doubt that sili cosis can develop independently of tuberculosis. A small group of French physicians are the only opponents of this conclusion; but they have prevented the inclusion of silicosis in the list of com pensable occupational diseases in France In 1937 Denny, Robson and Irvin published their first article on "The Pre vention of Silicosis by Metallic Alumin ium".14 A second article in 1939" re ported extensive chemical investigations. Experiments in vitro had shown that by adding metallic aluminium to a sus pension of quartz, the solution and the poisonous effect of quartz was stopped because the quartz particles were wrapped in an insoluble and imper meable coating of gelatinous hydrated aluminium. Animals could be protected against silica dust by adding 1 per cent, of aluminium dust to the total amount of dust. These amazing findings were corrobor for a long time. Courozier and Magnin19 assisted by Martin reported on a large number of observations contra dicting the opinion of this group; and, in 1941 a report was submitted by the Industrial Hygiene Commission stressing the fact that in France silicosis consti tutes a definite risk to approximately 200,000 workers. In its report the Com mission also presented a draft Decree concerning the compensation of silicosis and silico-tuberculosis, together with a draft notice concerning the technique to be used in making radiographic and radioscopic examinations. This report, prepared by Professor Duvoir has also been published in book form.10 ated by studies undertaken by R. Jae During the past few years the medical ger and F. Jaeger. 16 If very fine silica aspects of silicosis have been thoroughly and metallic aluminium were mixed in investigated: the differential diagnosis vitro in certain proportions, no free between silicosis and tuberculosis; the silica remained but all of it was trans X-ray findings; the chemical analysis of 4 ST0852UUI the lungs; the difficulties of expert opinion on compensation. All these questions are exclusively medical and will not be discussed here. The effects of other inorganic duBts have also been studied and the results published recently. Koelbch described "Iron Pneumoconiosis in Electric Wel ders".*1 In 18 out of 40 welders working with unsheathed steel electrodes, he found more or less marked deposits in the lungs. He explains this phenomenon as follows: "Fine iron particles are in haled into the alveoli and then trans ported to the lymphnodes They are gradually covered by fibrous tissue, but there is no proliferation of fibrous tissue and no generalised fibrosis as in silicosis, which develops only in welders working with certain sheathed electrodes." A critical survey of the literature on pneumoconiosis caused by sulphur was published by.ScHiAViNA.** Animal ex periments with injection of sulphur into the pleural cavity have shown results completely different from those of any other dust injected in the same way. is administered by an administrative board. The Secretary of State may grant disablement benefits to those workers who, though disabled by byssinosis, have not been employed sihce the com pensation scheme came into operation. In the United States, Neal, Schnbiter and Camnita** have published a "Re port of Acute Illness among Rural Mat tress Workers using Low-Grade Stained Cotton". The workers used a very lowgrade dusty stained cotton. Nearly three million families in 46 States of the Union were engaged in this type of work in 1941, and reports of illness came from 25 States. In one State alone over 700 cases of illness were reported. The disease is characterised by a sudden on set, occurring one and a half to three hours after the exposure, and is of short duration (24 to 48 hours). The symptoms are: headache, cough, pains in the joints, tightness around the chest, vomiting, diarrhoea, vertigo, rise of temperature, and high leucocytosis. The illness is caused by a specific bacteria, present in the cotton dust, which is called "cotton bacteria" by the authors of this report. The dust diseases caused by the in halation of organic dust have received more attention recently. Byssinosis is now a compensable disease in Great Britain in spite of the fact that its cause has not been satisfactorily explained. The Workmen's Compensation and Benefit (Byssinosis) Act of 20 Novem ber 1940 provides for the payment of compensation or disablement benefit in the case of male workmen who have died from or become totally and permanently incapacitated for work as the result of the respiratory disease known as bys sinosis. The compensation is given to men who have been employed for not less than 20 years in cotton card rooms or other specified parts of factories en gaged in the spinning of raw cotton, and Another recently detected disease is "bagassosis".*4 "Bagasse" is broken sugar cane after the extraction of the sugar, and has been used recently as a heat-insulating material. It causes an acute inflammatory lung disease among the workers, giving the radiological picture of influenza-bronchopneumonia. The pneumonia usually undergoes a slow solution and recovery follows, but chron ic cases also seem to occur with longlasting dyspnoea. A group of workers called "grainhandlers" were examined in the United States by Smith, Greenbtjrq, and Siegel.** These workers unload grain carrying ships or work on grain eleva tors, and some of them were suffering / ST 0852442 from "grainfever", i.e., general malaise, on tuberculosis in wartime", states pains, chills, fever. These symptoms that good results are obtained when used to set in two or three tours after certain conditions for a good picture are the men stopped working, and usually fulfilled, but that ``no diagnosis other disappeared the next morning. In some' than suspected abnormity" should be cases the symptoms appeared when the made from the miniature film. The same men first began to work, in other cases holds true for silicosis. In Germany, at the beginning of every season or where smaller films (24 x 24 mm) are whenever they had been away from used, the results were not satisfactory, work for several weeks, or when the dust according to Saupe*7, for detecting slight was concentrated, or when certain grains degrees of silicosis. In the United States were handled. of America two sizes of microfilms'are This disease may be a foreign-protein reaction, an allergic reaction similar to "sine fever". The X-ray pictures of the lungs sometimes showed pulmonary fi brosis or non-specific lung infections. Another effect of this kind of work was an irritation of the mucous membranes of the conjunctiva and the upper res piratory tract. used: 4x5 inches and 35 x 35 mm. It must be emphasised, however, that under certain circumstances the diag nosis of silicosis is more difficult than the diagnosis of tuberculosis. A report by Plunkett, Weber and Katz" gives a clear picture of the advantages of microfilms. It may be said, in conclu sion, that microscreen photography makes mass investigations possible at New Diagnostic Methods low cost and that this work can be done in a very short time (50 and more The diagnosis of silicosis and of other changes in the lungs caused by dust is possible only with the help of X-ray pic pictures in one hour); but if the screen picture is not very clear the usual X-ray picture has to be taken. tures. Since the usual X-ray pictures are Reliable apparatus for collecting dust comparatively expensive, a new method from the air exists, but the counting of has been elaborated, the microphoto dust particles of a size under 0.001 mm graphy of the X-ray picture seen on the usual radioscopy-screen. The great ad vantage of this method is that a large number of pictures can be taken in a short time at low cost. The cost of the usual X-ray pictures (14 x 17 inches) is 65 cents, while a microphotographic picture (4x5 inches) costs 6 cents, and one (35 x 35 mm) 3 cents. This method is therefore used for mass examination of soldiers, workers and children. under the microscope is very trouble some. Therefore, a simplified technique of counting has always been sought, so far without complete success." Another difficulty is to distinguish, in dust samples as well as in the lungs, be tween quartz particles (which are the only ones that cause damage) and other dust particles. X-ray diffraction has proved to be a good method.4 X-ray diffraction is also used for the measure Different sizes of microphotographical ment of these small particles.41 pictures are used in different countries. In Great Britain the usual size is 35 x 35 mm. The ``Technical Sub-committee Preventive Measures on Apparatuses for Mass Miniature Many years ago the United States (Indirect) Radiography", in its report Bureau of Mines established schedules of 6 ST 0852UU3 minimum requirements for respirators and other protective apparatus, and since then it has approved many pro tective respiratory devices. From time to time the list of such approved devices is published. enclosed conveying systems must be installed as far as possible. Before erect ing new premises or making important changes, the establishment must consult the Accident Insurance Association or the Office for the Combating of Dust. In 1940 a "Committee on Devices for the Protection of Workers from Dust" was set up in Germany. This committee publishes its findings concerning both suitable and unsuitable devices in the journal Staub (Dust), with descriptions and pictures of both. Among those de clared unsuitable are many old and wellknown respirators. Among'five devices for sand-blasting only three were found suitable. The directions for the construc tion of such devices prescribe an over pressure and a supply of at least 80 litres of air per minute in the headpiece. They have to be constructed in such a way as to make it impossible to go below this amount. For the time being the use of air taken from compressed air mains is permitted, but if the apparatus is con nected to such an air main a high-grade filter of activated carbon has to be inserted. On 1 August 1940 new regulations were published in Germany concerning the establishment of new plants using asbestos.4* They prescribed the installa tion of devices making it possible to measure the depression at various points of the ducts of the exhaust system. The machines must have individual drives to avoid raising dust. Pneumatic or other It may be mentioned here that in several countries the establishment of a water supply system and the use of wet drilling is prescribed for mines. In the United Stales a symposium on "Tuberculosis in Industry" was held in June 1941, in the Saranac Laboratory and the lectures given on that occasion were later published by the National Tuberculosis Association.41 Besides lec tures on clinical and statistical prob lems, there were lectures on predisposing factors (dust, fumes, gases, fatigue, trauma) and on certain industries (to bacco, needle trades, gypsum and ce ment industries, steel plants, foundries). According to the summary of the find ings by L. U. Gardner, Director of the Laboratory: "Of the environmental fac tors . .. the standard of living is univer sally accepted as significant. Of all the accessory environmental factors peculiar to industry, only free silica is accepted without challenge." Fumes and gases, lead, high temperature and humidity could not be proved to favour the de velopment of tuberculosis. Of the dusts only those high in free SiOs increase the susceptibility to tuberculosis. In modem tobacco and cigar factories there is little excess tuberculosis. * Williams, Enid: "Care of Miners on the Witwatersrand", in Iron and Coal Trades Re view, Vol. 140, 9 Feb. 1940, p. 260. * Winterer, R.: "Ergebniase der Reihenuntersuchungen fiber Silikoae bei Arbeitern dee Schaninalandbergwerkes", in Arthiv far - Qewerbepaihdtogie und Geweriehygiene, Vol. 10, 1940, pp. 24-36. * Sadpb, E.: "Berieht fiber cine rflntgenologisebe Reihenuntersuchung an Joachimsthaier Bergleuten", in Fortschntte auf dem Gebiete der Roentgen*trahlen, Vol. 60, Aug. 1939, pp. 163-171. 4 TJ.S. Department or Labor, Division or Labor Standards: Conference on Health and Working Condition* in the TrirState District, Minor Publications, No. 30,23 Apr. 1940. 7 ST0852U44 * Gaubatz E.: "Die Porphyrailikoee. Staublungenerkrankunsen von Arbeitern in den PorphyrsteinbrQchen der badischen Bergstrasse", in Arbeitsmedizin, No. 17, 1941, p. 68. * Cumminos, D. E.: "Industrial Hygiene in Steel Plant Practice", in Industrial Medi cine, Vol. 9, Industrial Hygiene Section, Vol. 1, July 1940, pp. 43-46. . ' Niqhman, C. E., and Kiessuno, 0. E.: Rock Drilling, National Research Project Report E--11 [Mineral Technology and Output Man Studies], Feb. 1940. * Hedenstedt, S.: "Das Vorkommen von Silikose und Silikotuberkuloee bei GuasstQckputiern dee Eisenwerkee Soderfors", in Ada Tuberculosea Seandinavica, Vol. 14, 1940, pp. 266-276. * Pennsylvania Bureau or Industrial Hy giene : A Study of Silicosis in the Silica Brick Industry, Minor Publications, No. 2, 1941. i' United States Public Health Sebvice: Pneumoconiosis among Mica and Pegmatite Workers, Public Health Bulletin, No. 250, 1940. 11 United States Public Health Sebvice' The Health of Workers in Dusty Trades' VII. Restudy of a Group ofGranite Workers, Public Health Bulletin, No. 269, 1941. " United States Public Health Sebvice: The Health of Workers in Dusty Trades: II. Exposure to Siliceous Dust (Granite Indus try), Public Health Bulletin, No. 187,1929, 11 Medical Reseabch Council: Chronic Pul monary Disease in South Wales Coalminers, Special Report Series, No. 243, 1942. United States Public Health Sebvice: Soft Coal Miners' Health and Working En vironment, Public Health Bulletin, No. 270, 1941. 11 United States Public Health Sebvice: Health and Working Environment of Nonferrous Metal Mine Workers, Public Health Bulletin, No. 277, 1942. " Clarke, B. G., and Moftet, C. E.: "Silicosis in Soft Coal Mines", in Journal of Industrial Hygiene and Toxicology, Vol. 23, May 1941, pp. 176-186. 17 "Dust Diseases in Russia", in Lancet, Vol. 242, 17 Jan. 1942, I, p. 85. ! Grieshauuer, W.: "Zub Fbaoe des Verh&l- tens der Lungen gegenOber Braunkohlenstaub"; in Archivfur Gewerbepathologie und Gewerbehygiene, Vol. 11, 1941, pp. 1-52. 11 Viquani, E.: Studio sull'asbestosis nelle manifatture di amianto, 1940; "Due casi mortal! di aabestoei polmonare", in Rassegna di Medicine Industrials, Vol. 11, Jan. 1940, f. 26-52; Mottura, G., and Faoiano, : "Anatomia patologica e patogenesi dell'asbestoei polmonare", in Rassegna di Medicina Industrials, Vol. 11, May 1940, pp. 234-284. ' Roemhild, L., Kempt, H., and Wedleb, H. W.: "Untersuohungen Ober die Lungenfunktion bei Asbestoae", in Deutsches Ar chie far KHnische Medisin, Vol. 186, 1940, pp. 63-70. 11 Siegel, W.,8mith, A.R1, and Gbxekbubg, L.: "The Dust Hazard in Tremolite Talo Min ing including Roentgenological Findings in Talc Workers", in American Journal of Roentgenology and Radium Therapy, VoL 49, Jan. 1943, pp. 11-29. ** Pobbo, F. W., Patton, J. R., and Hobbs, A. A.; "Pneumoconiosis in the Tale Indus try", in American Journal of Roentgenology and Radium Therapy, Vol. 47, Apr. 1942, pp. 507-524. I* Silicosis and Aebeetosis, by various authors, edited by Lanza, A. J. (Oxford University Press), 1938. Denny, T. T., Robson, W. D., and Ibvin, D.A.: "The Prevention of Silicosis by Me tallic Aluminium", in Canadian Medical Association Journal, Vol. 37, July 1937, pp. 1-11. Idem , Vol. 40, Mar. 1939, pp. 213-228. M Jaeqeb, R., and Jaeger, F.: "Kolloldchemisches und Histochemisehes sur Frags der , Lungenschadigungen durch Alummlumstaub. I Mitteilung", in Archie far Gewer bepathologie und Gewerbehygiene, Vol. 11, 1941, pp. 117-130. *' Goralewski, G.: "Zur 8ymptoinatologie der Aluminium-Staublupge", in Archie far Gewerbepathologie und Qewerbehygiene, Vol. 10, Deo. 1940, pp. 384-408; and "Klinik der Aluminiumlunge", idem, Vol.. 11, 1941, pp. 108-116. ii Joetten: "Zur Frage der VerhQtung von Sllikose durch metallisches Aluminium", in ArbeitsschuU, 1940, pp. 252-254. " Coukozieb, M., andMaonin.J.: "Deuxoents cinquante cas de silicose. Lee formes de debut", In La Mtdecine duTravail, Vol. 13, 1941, pp. 5-55. 10 Duvoib, Professor: "La prevention et la re paration des pneumoconioses" (silioe, ardoiae, amiante, talc), Paris, Imprimerie Nationale, 1941, 450 pp. " Koklsch: "Eiaenstaublungen bei Ehktroschweissern", iii ArchivfdrGewerbepathologie und Gewerbehygiene, Vol. 10, 1940-1941, pp. 510-S2S. Schiavina, G. P.: "Contribute critioo e sperimentals alio studio della tiopneumoncomosi", in Rassegna di Medicina Industrials, Vol. 12, Apr. and May 1941, pp. 173-185, 244-266. ** Neal, P. A., Schnkitsb, R., and Caminita, B. H.: "Report on Acute Illness among Rural Mattress Workers using Low-Grade Stained Cotton", in Journal of the American Medical Association, Vol. 119, 1 Aug. 1942, pp. 1074-1082. 8 $T08521flt5 >4 Castledzn, L. I. M., and Hamilton- Pater son, J. L.: "Bagaaaosis", in British Medical Journal, 24 Oct 1042, VoL II, pp. 478-180. * Smith, A. R., Gbkhnxubo, L., and SiegeL, W.: "Respiratory Diseases among Grain Handlers', in Industrial Hygiene Bulletin (Division of Induatrial Hygiene, New York State Dept of labor), VoT 20, Jan. 1041, pp. 33-30. > Medical Research Council: Report of Committee on Tuberculosis in War-Time, Special Report Series, No. 246, London, 1042. it Sacra, E.: "Erfahrungen beim Vergleich von Scurmbildaufnahmen mit Groesfilmen in Rahmen von Staubarbeltanelhenuntamuehungen", in Fortschritte auf dam Gebiete dor Rontgenstrahlen, Vol. 62, Sept. 1040. pp. 146-150; "Zur Frags der Ritatgenrelhenuntersuchung von Btaubarbeitern mittela dm Scbirmbildverfabnna", in Ar&iofOr GewtrbtjxUhologis und Geuerbehygiene, Vol. 10,1040, pp. 03-06. Plunxett, R., Weber, G., and Kan, J.: "Comparative Value of Roentgenphotographio Methods", in American journal of Public Health, Vol. 31, Aug. 1011, pp. 772776. it Ohlheiseb, H. R., and Lawhence, L. B.: "Dust Counting--Simplified Technic", in Journal of Industrial Hygiene and Toxi cology, Vol. 22, Dec. 1010, pp. 472-476; Hmii, W. B.: "Modified Eyepiece Mi crometer for Use in Dust Counting", in Journal of Induttrial Hygiene and Toxi cology, Vol. 23, Apr. 1041, pp. 148-150. < Bebielhamek, L. H.: "X-ray DiffractionImportant Tool in Pneumoconioses Re search and New Method of TissueAnalysts", in Journal of Induatrial Hygiene and Toxi cology, Vol. 23,' May 1041, pp. 163-175; Untied States Bubeau or Mines, R.I.: Quantitative Analytic by X-ray Diffraction, I. Determination ofQuart* (Ballard, J. W., Oshcbt, H. L, Schbknx, H. H.), June 1040, p. 3520; GIetnxb, H.; "Die Rdntgenfeinstruktoruntersuchung an Gewerbestauben", in Archie far QeuerbepatMogie und Geuerbehygiene, VoL 0, 1030, pp. 377-300; also "Rbntgenfeinstrukturuntersuchungen an Ponellanstaublungen", in Archie far Geuerbepathologie und Qeuerbehygione, Vol. 10, 1040; and "Die Rontgenfeinstruktunmtersuchung als medisinische Untersuohungsmethode", in ArbeiieschuU, 1040, p. 108. Hai.sebstadt, H.: "Ober Grtiesenbestimmung unaiohtbarer Tellchen", in Staub, VerojfentUchungen der StaubbekampfungsstsBs beim Vtrbande der deuteehen gewerblichen Btruftgenottenedufien, Vol. 13, 1010, pp. 151-180; Wdbdiaann, G., and Fbvtbb, G. ". "Versohiedene Metnoden lur experimentellen GrOasenbestimmung kleinater Teilohen mit Rdntgenstrahlen", in Fortschritte auf dem Gebiete der Rontgenetrahlen, Vol. 61, Feb. 1040, pp. 110-127. *' International Labocb Omen; Induttrial Safety Survey, Vol. XVII, July-Sept. 1941, p. 101. < Saranac Laboratory Symposium, 1041; Tuberculosis in Industry, National .Tuber culosis Association, New York, 1042. 0