Document mbzBjvrrQOz90Z9xmQXJqm7m0

FILE NAME Quebec Asbestos Mining Association QAMA DATE 1965 DOC QAMA007 DOCUMENT DESCRIPTION Journal Article - Special Asbestos and Cancer  THE THE - , a CODIAN CODIAN .if MEDIO 4 MEDIO ae , R a * et ON VOLUME 92 NO 19-1963 ASSOCIATION ASSOCIATION OURE JOURNAL JUN 7 JOURNAL 1965 1965 ME MD ED II CCAAL LE E . MEDICINE MEDICINE DE MAY 8 8 MAI CA CANANDIEA NNEDIECAN NADNIENENE - OORIGINALRIGINAORIGINAL L AARTIRCLESTICARTLICLEESS tea eres Page Page Radiation Radiation Canada VII Protection Part Industrial in Hygiene in the Field of Role of Radiation Protection N. Williams . 993 The University of Maratoba Follow Study A Prospective Investigation of Cardiovascular Disease Part II Build Blood Pressure and Electrocardio- graphic Factois Possibly Associated with the of Development Coronary Heart Disease F. A. L. Mathewson C. Brereton W. A. Keltie and G. I. Paul ; 1002 The Chilliwack Respiratory Survey 1963 Part III The Prevalence of Respiratory Disease in a Rural Canadian Town D. O. Anderson B. G. Ferris Jr. and Rosalie Zickmantel 1007 The Use of the Mercury Inhibition Test in the Recognition of Virulent Strains of Staphylococci in a Hospital Environment F. Turgeon J. deriesand A. G. Thompson 1017 REPORT CASCASE E REPORT tricular Fibrillation Ver J. G. Gillis with Myocardial Infarction . i. Page 1031 EDI ORIALS AND ANNOTATIONS The Association Asbestos and Malignancy Malignancy Malignancy teres The AssociatAs oiciatoion n Revolting and - Hoy Times Have Changed DIODE 1031 1031 1036 ERS LET ERS TO THE THE JOURNAL JOURNAL JOURNAL Medical Tra The Ralation Medical Aid Chappel Countries G. Screech Tot fic Accidents D. Geggie Baird notherapy Symbol Cardiac A. Baird ieee cece cere eee teens RalMat.ion Minuck ProteNctiaon haProstection Petree ees seer ees a ese eet e este ewes een aes Rodale R Rodale -. PDPD Sourby Sourby 1037 1038 103 1039 1039 1039 1039 1039 SPECIAL REPORT SPECIAL The Recom endations Asbestos and Cancer The Report and Recommendations Working of a Group Geographical Convened under the Auspices Committee of the Geographical Pathology Committee of the International Union Against Cancer . .. 1020 ASSOCIATION ASSOCIATION NEWS Go 1 Medical Practice in the Care of the Narcotic Addict A Report Prepared by a Special Committee Appointed by the Executive : Association Committee of The Canadian Medical J. K. W. Ferguson Chairman G. H. Ettinger G. E. Joron J. J. Lederman and D. J. MacKenzie .. 1040 SHORT COMMUNICATION A Survey of Toxoplasmosis Among Mentally Retarded Children N. A. Labzoffsky N. A. Fish E. Gyulai and F. Roughley . . 1026 CURRENT DRUG THERAPY Pyelonephritis Drugs for Acute Pyelonephritis J. Ruedy ... . . .. 1029 NEWS AND VIEWS ON THE OF ECOECONMICSNOMIECCONOMSICS OF MEDICINE Comments Comments on Medical Services Insurance continued .... 1047 Obi paries cc oo. c . ec . e 1043 | Books Received . ...... 6 Provincial | Forthcoming 0) 18 News PostPgostgraduateraduate Courses ., Meetings 6 Medical News in BrBriief ef 38 Advertisers Index of Advertisers .... $ it nat Ti Published every week by THE CANADIAN MEDICAL ASSOCIATION - L'ASSOCIATION CANADIENNE MEDICALE 150 St. George Street Toronto 5 PRICE Printed 1.00 PER COPY PAYABLE IN ADVANCE SUBSCRIPTION RATES in Canada by MURRAY PRINTING & GRAVURE LIMITED ON DVERtising Page 42. 2973 WESTON ROAD COPYRIGHTED COPYRIGHTED WESTON ONT Authorized as Second Mail by the Post Oflice Departme it Ottawa and for payment of postage in cash FOR THE PSYCHONEUROTIC PATIENT WHO NEEDS MORE THAN TIME AND REASSURANCE ALONE * * * * * # # eH & MERCK SHARP & DOHME OF CANADA LIMITED MONTREAL +10 f ASBESTOS AND CANCER Canad Med Ass J. May 8 1965 vol 92 1 | of Ch chr obs ad Berk by by Y 1020 SPE measuring measuring the resistance resistance or sensi- sensi- to mercury salts have been Surogenes was difference noted but the agar preferred as it is technically easier to to mercury appears to be associ- biotnicceresistance but no difference in ween the two groups was demonstrated of intracerebral injection of mice The t may a as a screening procedure and have place the relationship between the resistance to and to antibiotics We are grateful to Miss Thibeaudeau and Mrs. J. Small for their technical assistance REFERENCES 1. MOORE .; Lancet 2 453 1960 2. SIMPSON D. M Med Sei J. Canada 20 120 1964 3. CADNESS B. et al Lancet 1 730 1943 4. Fisk A Brit J. Exp Path 23 311 1:40 5. WECKMAN1957 5. WECKMAN G. REED L. 1938 B. G. AND CATLIN B. W J. J. AND MUENCH FL Amer J. Bact 73 147 Hyg 27 493 7. 7. BARBER M. HAYHOE G. J. AND WHITEHEAD J. E. M Lancet 2 1120 1949 8. BLAIR J. E. AND CARP M J. 4. Mr. A. 166 1192 1958 9. ELEK S D Ann NY Acad Sc 65 85 1956 10. ELEK S. ) AND CONEN P. E Brit J. Exp Path 38 673 1957 11. FRAPPIER A. SOXEA S Biol 14 152 1955 AND PANISSET M. Rec Canad Asbestos and Cancer The Report and Recommendations of a Working Group Convened Under the Auspices of the Geographical Pathology Committee of the International Union Against Cancer meet EDITOR'S NOTE October 1964 the New Academy of Sciences sponsored an international meet ing on the biological effects of asbestos Following this meeting some 40 delegates from Australia Canada Finland France Germany Great Britain and Ireland Italy South Africa and the United States were invited to study the vast amount of information which had been presented with a view to the organization of an international study of asbestos and cancer The terms of reference of this Working Group covered three major aspects of the problem epidemiology pathology and experimental pathology and physics and chemistry The findings of the Working Group and their recom mendations arising from these studies are recorded slightly abridged form in the following report THE ASSOCIATION OF EXPOSURE TO ASBESTOS DUST AND CANCER THE main types of asbestos of commercial interest are amosite anthophyllite chrysotile crocidolite and tremolite There is evidence of an association between exposure to asbestos and malignant neoplasia This has been established mainly on information from Germany Italy South Africa the United Kingdom and the United States of America The types of tumours which have been shown to be associated with exposure to asbestos dust are 1. Carcinoma of the lung 2. Diffuse mesothelioma of the pleura and peri toneum There is some suggestion of an association also with gastrointestinal carcinoma and possibly with ovarian tumours The latent period between first exposure to the dust and detection of the related tumours is many years usually 20 or more Instances up to 60 years have been reported For this reason further cases of these associated tumours will be expected to occur for many years to come even if dust exposures are now greatly reduced Present evidence indicates that the associated carcinomas of the lung are not limited to exposure to any one type of asbestos fibre However further investigations are urgently needed to establish whether the degree of risk is importantly related to the type of fibre inhaled In the case of mesotheliomas evidence from several countries suggests that exposure to crocido- lite blue fibre may be of particular importance but it cannot be concluded that only this type of fibre is concerned with these tumours and further investigation of this problem is needed Certain types of asbestos fibres in the virgin state have been found to contain oils waxes and other organic matter In addition asbestos fibres readily absorb hydrocarbons subsequent to mining Small or trace amounts of various elements such as nickel and chromium are also found associated with some types of fibre The possible role of such associated materials in the development of tumours following exposure to asbestos dust is not yet clear These findings when considered in relation to the great increase in the use of asbestos for many purposes in all countries suggest that a more serious and widespread hazard from exposure to asbestos dust may exist than is widely appreciated ~ a Canad Med Ass J. May 8 1965 vol 92 SPECIAL REPORT ASBESTOS AND CANCER 1021 RECOMMENDATIONS ON PROBLEMS REQUIRING EPIDEMIOLOGICAL STUDY 1. That the relationship of fibre type to the risk of developing asbestosis carcinoma of the lung and mesothelial and other tumours be investigated International and intranational comparative studies of mining and other populations exposed to b It is also recommended that since incidental to asbestos dust may occur in certain exposure trades and occupations attention be directed to the handling and transporting of asbestos pipe fitting and the building and building in- dustries c It is recommended that surveys be made to study environmental and community exposures including populations near mines and factories and only one type of fibre are recommended Studies of the effect of exposure to different types of asbestos fibre within a country are likely to be of special value but studies of groups exposed to apparently similar fibres in different parts of the same country are also likely to be informative 2. That the relationship of dust dosage includ- ing concentration and duration of exposure and the composition and physical state of the dust to the incidence of asbestosis carcinoma elsewhere d It is recommended that general population be made nationally and internationally to surveys establish by standardized methods in areas of presumed high and low exposure to asbestos dust the prevalence of asbestos bodies and fibres e It is recommended that surveys of asbestosis in domestic and wild animals be extended to areas of high and low exposure 6. Epidemiological Methods of the lung mesotheliomas and other cancers be studied a General In addition to the usual information about the Comparative studies in factory populations in the asbestos textile and other manufacturing processes using asbestos are likely to be useful especially when there are records of past dust measurements In any prospective studies of new entrants the measurement of dust by a standardized method should be regarded as an essential part of the in- individual collected in such surveys special attention should be directed to a detailed social including smoking habits occupational environmental and medical history from early childhood to elucidate any possible exposure to or association with any type of asbestos or other dusts A study of the family unit or household may be of interest in view of the occasional reports of significant vestigation 3. That the effects of removal from further ex- posure to asbestos dust be investigated It is important to establish the subsequent morbidity and mortality from asbestosis and the mortality from cancers associated with exposure to asbestos in population groups no longer exposed to the dust 4. That further investigations be made of past and all future cases of diffuse mesothelial tumours of the pleura and peritoneum to establish any association with asbestos and neighbourhood and household exposures In view of the association between exposure to asbestos dust and pulmonary fibrosis and its complications it is important to obtain as much information as possible about morbidity and mortality from all causes with particular attention to asbes- tosis chronic bronchitis and emphysema bronchiectasis diffuse interstitial fibrosis pneumonia tuberculosis cor pulmonale carcinoma of the lung diffuse mesothelial tumours of the pleura and peri- toneum gastrointestinal tumours and ovarian tu- mours b Clinical Criteria other factors These tumours should be diagnosed on the criteria suggested by the Panel on Pathology see below and the diagnoses should be reviewed by a panel of pathologists with experience of these rare tumours The tumour and lungs should be Symptoms It was agreed that in all surveys the presence or absence of cough sputum dyspnea and chest pain should be recorded as a minimum This should be recorded using a standardized questionnaire investigated for the presence of asbestos by physi- cal and chemical methods see below 5. That studies of morbidity and mortality be extended to asbestos populations that have not so far been widely investigated a It is recommended that special attention be directed to surveys in the insulating asbestos cement and asbestos products industries and other plants in which asbestos is regularly used Signs It was agreed that when physical examination was possible the minimal observations should include the presence or absence of clubbing of fingers cyanosis and basal rales in the chest It was agreed that the measurement of sputum volume first hour on rising and degree of puru- lence recorded in a standard way,,was useful in association with the questionnaires for assessing \ 1022 SPECIAL REPORT ASBESTOS AND CANCER Canad Med Ass J. May 8 1965 vol 92 the prevalence of bronchitis and this may be rele- vant to the disability caused by asbestosis The epidemiological usefulness of examinations of sputum for asbestos bodies and fibres is at present uncertain but needs investigation Mediastinal tissues should be examined for evi- dence of neoplastic infiltration and for tuberculosis Peritoneum Parietal and visceral fibrosis in the peritoneum such as parietal plaques and sugaricing of the spleen should be recorded c Classification of Chest Radiographs of Asbestos Individuals There is no international or national standardized classification of the radiological appearances of asbestosis It is recommended that a scheme based if possible on an extension of the I.L.O. Classification 1958 be developed The aim should be to specify separately and record semiquantitatively the principal radiological features seen in asbestosexposed groups but exposure to mixed types of dust is not uncommon and the appearances may therefore include those caused in part by other pneumoconioses It is recommended that a working group be set up to develop and test a new international classifi- cation d Lung Function Assessment The preferred lists of lung functions to be used will vary according to the type of survey and the facilities available A list of minimal and additional tests likely to be of use is as follows Minimal Forced vital capacity F.V.C. Forced expiratory volume over 1 sec F.E.V b Microscopic Examination It is recommended that at least six sections be examined from the lungs before the degree of asbestosis is decided and these blocks should be taken from specific sites and identified in the follow- ing standard manner 1. Apex of right upper lobe pleural surface 2. Right middle lobe lateral pleural surface 3. Right lower lobe middle of basal surface 4. Left upper lobe central section 5. Lingula central section 6. Left lower lobe central basal section In addition sections should be taken from the bronchi and peritracheal and peribronchial lymph glands and from any suspicious or abnormal tissue c Assessment of the Severity of Asbestosis It is recommended that this assessment should be based on the severity of interstitial fibrosis and the amount of tissue involved The proposed scheme is as follows EXTENT OF LUNG INVOLVEMENT DEGREE OF ASBESTOSIS Slight = Slight < DEGREE OF INTERSTITIAL FIBROSIS _- Slight Additional Transfer factor diffusing capacity of lung for carbon monoxide breath method Lung compliance Standard exercise test Peak expiratory flow Airways resistance RECOMMENDATIONS ON PAthology and EXPERIMENTal PathologY 1. Diagnosis of Asbestosis a Macroscopic Examination At necropsy the parietal pleura should be stripped if possible with the thoracic contents It is desirable that at least one lung be inflated with fixative and whole lung sections be prepared It is recommended that special note be made of the following Pleura for thickening and plaques defined as localized areas of stiff hornlike material The site and size of all pleural lesions should be recorded Lungs The presence of interstitial fibrosis bronchiectasis cystic change tuberculosis pneumonic consolidation and tumours The site of any tumour should be recorded as precisely as possible Moderate Moderate =~Moderate Marked ~ Marked- Marked A category of minimal asbestosis is also pro- posed to describe slight focal fibrosis in the region of the respiratory bronchioles associated with the presence of asbestos bodies such changes are commonly confined to sections taken from the bases of the lower lobes This scheme puts more emphasis on the extent of the lesions than the degree of fibrosis which should be averaged for the six sections Thus a lung with moderately extensive disease but only slight severity of fibrosis is graded as moderate asbestosis The use of an average assessment of the six sections makes it impossible to have a grading of slight involvement and moderate or marked degree of fibrosis d The Detection and Significance of Asbestos Bodies and Fibres Sputum The presence of asbestos bodies and fibres is an indication of the exposure to asbestos dust and not evidence of asbestosis It is therefore suggested that Canad Med Ass J. May 8 1965 vol 92 SPECIAL REPORT ASBESTOS and CANCER 1023 the bodies should be referred to as asbestos bodies and not by the previously used term asbestosis bodies Because of their sporadic appear- ance and in the case of fibres their relation to recent dust exposure quantitative assessment of bodies and fibres in sputum is not in the light of present knowledge a very useful procedure but might become more useful when further investi- gated In sputum detection by direct examination under a coverglass and the use of phase contrast oblique illumination or narrowed condenser diaphragms is proposed If sputum concentration is used anti- formin or Eusol treatment is recommended Lungs From fresh lungs the greatest number of positive results are obtained from smears from the base of a lower lobe of the thickness of a thick blood smear as for malarial parasites dried and mounted in balsam A rough quantitative examination by power magnification is easy and practicable For fixed lungs the smear technique is of limited value and unstained sections 30 microns thick are recommended mon in the peritoneum where the surfaces often remain separate but covered by isolated plaques and nodules or diffuse infiltration Only those meso- thelial tumours in which serosal spread is unequivocal should be termed diffuse A few benign diffuse mesotheliomas have been described Almost all diffuse mesothelial tumours show evidence of malignancy by direct infiltration of adjacent tissues and organs and metastases to regional lymph nodes The differentiation from metastatic tumour is the main problem in diagnosis and can only be made with complete certainty by the exclusion of all other sources of tumour at necropsy Because of the tendency of the tumour to surround and infiltrate subserosal organs these organs most commonly come under suspicion as points of origin The possibility that the primary growth may have been surgically removed must be borne in mind b Microscopic Diagnosis is possible because the growth commonly shows histologic patterns which occur infrequently in other tumours and especially those which might metastasize to serosal membranes Particularly helpful is the presence in some diffuse mesotheliomas of a mixed structure of malignant ele- Fibres For investigation of asbestos fibres in lung sec- tions microincineration acid treatment and ex- amination by contrast are suggested Morphologically the fibres appear as straight rods of varying lengths and thickness but with longitudinal shredding and in the thicker fibres smaller fibrils may be recognized While there are other structures described as asbestos bodies or curious bodies little difficulty is found in distinguishing the genuine from the others These other types usually have a carbon centre and a shape which is other than linear but the body that can mimic an ashestos body completely is the small one found in talcosis which may be tremolite a form of asbestos ments of both epithelial and mesenchymal charac- ter or other diverse combinations Growths in which only one type of cytoarchitecture is present may also have a highly distinctive pattern for ex- ample 1 a tubular or papillary pattern in which the tumour cells show marked uniformity and are cubical or flattened 2 masses of collagen in which there are either a cleft spaces lined or occupied by tumour cells or b fine hyaline strands which form complex meshworks and laminated bundles Other examples of these tumours may have an entirely specific structure presenting the appearance of a spindle cell sarcoma or of an anaplastic tumour Because of the difficultiny clearly distinguishing on histologic grounds alone some of these growths from metastatic tumours cases diagnosed from Chemical Analysis of Lung Tissue Where possible blocks of tissue from the six areas chosen for histological study should be taken and the amount of collagen relative to total proteins estimated by the standard hydroxyproline methods The results of collagen estimations should be expressed in absolute amounts and as percentages of defatted dried lung tissue.4 biopsy material should be called probable mesotheliomas In epidemiological studies precise details of the pathological evidence on which the diagnosis was based should be stated c Histochemistry Most of the mucoid material within mesothelio- mas although often intimately associated with the surfaces of the tumour cells is extracellular Intra- 2. Diagnosis of Diffuse Mesothelial Tumours a Macroscopic The salient characteristic of the diffuse meso- thelioma is its predilection to spread along the serosal membrane in which it occurs In the pleural cavity the entire surface may become replaced by a continuous layer of tumour owing to symphysis of the pleural surfaces This is uncom- cellular or intratubular mucin of an adenocarcinoma will usually take mucicarmine or PAS stains The absence of these reactions in a tumour which contains mucoid material can when taken with the other features be useful additional evidence of a mesothelial tumour Hyaluronic acid is often present in mesothelial tumours The demonstration of its removal from the tissue sections by specific hyaluronidase prepa- 1024 SPECIAL REPORT ASBESTOS AND CANCER Canad Med Ass J. May 8 1965 vol 92 rations is a useful histochemical test but since the acid is soluble in water the test requires that the tissues be fixed in a special precipitating fixative such as formol alcohol acetic acid It also appears likely that the quantitative measurement of hyaluronic acid in effusions where this polysaccharide has been isolated and chemically characterized may well become a reliable method for assisting in the diagnosis of mesothelioma but it is emphasized that positive results for both the histochemical and chemical tests for hyaluronic acid are found in only a proportion of cases of mesothelioma and they should not be used as sole diagnostic criteria d Exfoliative Cytology The contribution to the diagnosis of diffuse malig nant mesothelioma by exfoliative cytology of serous - fluids requires 1 that the exfoliated neoplastic mesothelial cells sufficiently resemble exfoliated neoplastic mesothelial cells to allow them to be recognized as having a mesothelial origin and 2 that they also possess the generally accepted features of malignancy The latter are not often present so a definite diagnosis of mesothelioma is then difficult Usually mesothelioma cells while atypical do not appear malignant but still show evidence of mesothelial origin From cytology of the serous fluid it is possible to be strongly suspicious and in a few cases confident of the diagnosis of mesothelioma but usually its presence can only be re- ported as possible The diagnosis of malignant mesothelioma by ex- foliative cytology requires a familiarity with the neoplastic mesothelial cell Mesothelial hyperplasia and hypertrophy can easily be mistaken for malignant mesothelioma and vice versa It may be imprudent to do more than suggest malignant mesothelioma if there is not good supporting clinical radiological or biochemical evidence The exfoliated malignant mesothelioma cell must also be distinguished from the adenocarcinoma cell by far the commonest malignant cell recovered from serous fluids This cell is well described in standard texts of exfoliative cytology e The Use of Tissue Culture in the Diagnosis The various manifestations of mesotheliomas in some cases cause difficulty in distinguishing such tumours from bronchogenic carcinoma metastatic ovarian carcinoma fibrosarcoma etc. It is therefore recommended that where possible biopsy specimens of pleural and peritoneal neoplasms be studied after short passage a in vivo and b in vitro to determine whether the rate of growth and morphology after transplantation can provide useful criteria for a differential diagnosis of meso- theliomas To achieve this it is recommended that clinical pathologists seeing these tumours operate with workers in experimental carcinogenesis who . are using culture methods 3. The Contribution of Experimental Pathology It was agreed that various types of asbestos induce in many species of animals lesions similar to those seen in human cases of asbestosis meso- thelioma and carcinoma of the lung but the need for more precisely planned experiments was emphasized The desirability of using healthy animals of known response to asbestos under quantitative conditions of exposure by inhalation feeding and parenteral injection at several sites was accepted Experiments in great variety are being undertaken in many parts of the world particularly in Canada Great Britain South Africa and the U.S.A. The prospect of providing standardized samples of chrysotile amosite crocidolite tremolite and antho- phyllite asbestos for experimental work was wel- coined It was agreed that there was a need for improving methods of identifying the type of asbestos in submicroscopic fibres in tissues Further studies of the rate of formation and resistance to destruction of asbestos bodies in different species of animals may be useful It is recommended that there be closer collabora- tion between clinical and experimental pathologists and other scientists in the field of experimental pathology biochemistry and biophysics as applied to the problems of the biological action of asbestos 4. Proposal for Pathology Reference Panels It is recommended that central consultation and reference panels be set up on regional national and international levels These panels will a Assist in establishing standards for pathological classification of asbestosis b Serve as consultation centres for diagnosis of mesotheliomas and other tumours associated with exposure to asbestos c Provide for general exchange of pathological material related to asbestosis and its associ- ated tumours It is further suggested that a comprehensive atlas on the pathology of mesotheliomas should be prepared RECOMMENDATIONS RELATING TO PHYSICS AND CHEMISTRY 1. Reference Samples of Asbestos for Experimental Work It is anticipated that there will be an expansion of demand for asbestos of various types for bio- logical and other studies It is at present impossible to predict the biological effects of differences in mineral composition size distribution associated organic matter and trace metals in different samples of asbestos Also fibres from a particular mine may vary in composition and in the amount of absorbed material Canad Med Ass J. May 8 1965 vol 92 Special RepORT ASBESTOS AND CANCER 1025 It is therefore recommended that a Standard reference samples of respirable size of amosite chrysotile crocidolite tremolite and anthophyllite be prepared from as pure parent material as possible and held at the Pneumoconiosis Research Unit P.R.U. in Johannesburg for distribution to centres requiring them These standards should also serve as references for comparison with larger amounts of material as may be required for inhalation or chemical extraction It is proposed that samples of chrysotile from different countries example from Arizona Havelock Swaziland Quebec and Shabani Southern Rho- desia included in the reference collection b The standard samples be analyzed and characterized quantitatively by Chemical and spectrographic analysis Optical and electron microscopy for determination of shape size distribution and optical properties such as refractive indices extinction angle etc. ray diffraction analysis by the powder tech- nique .. Specific surface measurement by low tempera- ture gas adsorption Determination of amount and type of organic ~ matter present c Oils and waxes isolated from asbestos be prepared and also distributed through the P.R.U. Johannesburg d When the standards have been collected and prepared the P.R.U. Johannesburg will notify workers of their existence through the U.I.C.C. Bulletin and any other appropriate channels 1. Identification and Quantitative Assessment of Asbestos in Tissues In tissue sections identify the type of tative studies of the it may be only possible to asbestos present For quanti- amount present in any organ such as the lung it is necessary to analyze repre- sentative samples of the organs It is recommended that Tissue sections should be treated to remove or- ganic material for instance by ashing or treatment with active oxygen but this will not remove the asbestos bodies completely and chemical treatment may be necessary to free the fibres The best method for this is not known but treatment with acetic acid may be useful Identification of the type of fibre can only be made on free asbestos fibres and not on fibres inside asbestos bodies It is recom- mended that methods of distinguishing asbestos from other fibres which may be present be further investigated This can probably best be done by phase contrast or polarized light microscopy It is also recommended that the treated sections be examined by electron microscopy for recognition of submicroscopic fibres For large samples of tissue acetic acid hydrogen peroxide and formamide methods be tried as they appear to be superior to ashing but the best method of extraction of mineral matter from tissue is not yet known and needs further study However the quantitative determination of asbestos in the residue obtained in this way is difficult but could be based on chemical analysis ray diffraction or fibre counts It is recommended that methods for concentrating such asbestos and separating different types of asbestos from each other be further investigated Reprints may be obtained from the Institute 790 Bay St. Toronto Ont National Cancer REFERENCES International 1. Miller I .: Amer Rev. Resp Dis 88 473 1962 Labor Office Occup Safety Hith 9 63 3. 3. GLOYNE S. R Tubercle 14 445 1933 4. HARINGTON __J S. AND KILROE T. A. Arth Environ Health Chicago 9 395 1964 5. WAGNER J. C. MUNDAY D. 1. AND HARINGTON J. .: J. Path Bact 84 73 1962 PAGES OUT OF THE PAST FROM THE JOURNAL OF FIFTY YEARS AGO WHAT IS TO BE DONE Nor is the death from asphyxiating gases a sudden and articles in German news- hypocritical painless widlelathhaveas us believe In very small doses it first papers cessation of breathing reflexly produces a temporary of the nasal mucous membrane Next through irritation inhibition of necessity ceases the gas is drawn when this and on account of its into the other respiratory passages solubility in moisture it attacks the respiratory mucous membranes producing violent coaftatrhershe Tmheemblraatneressecqauuesle^d are results of the disintegration direct union of the chlorine with their proteins either by the formation of hypochlorous and or by chloric acids and the evolution of nascent oxygen There is fre- quently a purulent discharge with inflammation bronchitis hamorrhage and pneumonia All these symptoms have been observed in rescued soldiers The sufferer may consider- die before pneumonia ensues and in the case of able concentration of the gas over one in a thousand dyspnea coma and death rapidly follow But meanwhile what is to be done Can we bring ourselves to imitate the methods of the enemy To blow steam or atomized water from a spray into the fumes may be effective but it is to be remembered that chlorine water blisters the skin and causes acute inflammation of the conjuctiva A combination of wet respirators and water sprays would be useful and a means of creating a violent updraught of air some distance kienrofsreonnte owfoutlhde storedniclhuetes thbey means of burning gasoline or Meanwhile cloud of vapour as to render it less noxious take some comfort in the thought that it is but we can rarely that atmospheric conditions will render the use of this diabolic means of warfare possible Already if we can our enemies have been caught in their boewln ievEe drieptoortrs ial Canad Med Ass J. 5 516 1915