steel dentures

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is only a step from this to the theory of specificityamong the streptococci, and in rheumatism we arefamiliar with the organisms of Beattie, Poynton andPayne, and Birkhaug. All observers agree, however,that most cases of rheumatism do not yield organismseither from the blood or in local lesions, and none ofthese has yet been recognised as the specific cause.The latest claimant is the " Streptococcus cardio-arthritidis " of J. C. Small, which has lately attractedsome attention. Its claims, as now set out 32 aredifficult to appraise. Only three of Small’s strainscome from the blood ; most of them are from thethroat, where streptococci abound ; and no evidenceof any normal controls is given. Though the organismis said to be non-haemolytic, to vary in its sugarreactions, and to be specific in its agglutinations, nocultural characteristics are adduced which wouldmake it possible to recognise the strains. Many ofthe references are " in the press," others are " personalcommunications," and on the whole, technical detailsare inadequately presented. It may be noted thattests of cutaneous sensitiveness are on the wholenegative, which is remarkable, since other workershave recently claimed specific results with theirstrains and, in fact, a surprisingly large number ofrheumatic patients are Dick-positive. The author’sparsimony in bacteriological information, however,is balanced by his generosity in clinical detail. Patientsare treated by vaccines, by " soluble antigen," madeby washing the streptococcus, and by antisera, andespecially by concentrated globulin precipitates.Striking results are claimed ; very exact and ampleclinical details are quoted. Opsonic indices andagglutination titres show a speedy upward change ;chorea disappears ; valvular lesions are ameliorated.In considering these reports it should be rememberedthat a relatively new claim to the identification ofthe causal organism of rheumatic fever lends itselfto criticism. Many independent investigators haveincriminated the streptococcus, whereas few haveproduced evidence to show that other organismsmight be to blame ; but even if its guilt be proved thequestion would remain, whether one strain of strepto-coccus is specific for the disease or whether a varietyof strains may cause it. The trend of opinion all overthe world appears to favour a fresh trial of strepto-coccal antisera for many diseases whose aetiology isnot as yet completely understood.

INDUSTRIAL ACTIVITY AND FATIGUE.THE history of human endeavour in the past,

whether in the construction of pyramids, cathedrals,industrial works, or engineering plants, has too oftenbeen a tale of effort forcefully directed by task-masters with but little care for the well-being of thelabourer so long as the task progressed. Not untilthe beginning of this century did it begin to dawrlupon employers, as a class, that maximum productionis contingent on the fitness of the worker. In theeighth annual report 3 of the Industrial FatigueBoard an account is given of the way in which thework of the Board started and has since progressed,and of the gradual expansion of its activities. Theproblems recently submitted to the Board for solutioncover a wide field and are of considerable importance.They include hours of work in relation to the valueof rest pauses during long spells, and to the double-shift system for women ; the physiology of ventilationwith special regard to heating by the panel system ;vision and lighting ; accident causation ; vocationalguidance, and other matters. Government depart-ments and industrial associations have soughtinformation as to mining conditions, telegraphists’cramp, weight-carrying, and sickness in the cottonindustry and printing trade. A further line ofactivity has been concerned with research into the ’,principles governing muscular activity, muscular ’

effort, and the effects of noise and vibration. I2 Amer. Jour. Med. Sci., 1928, clxxv,, 638.

3 Eighth Animal Report of the Industrial Fatigue Research Board, to Dec. 31st, 1927. H.M.S.O., 1928.

Laboratory research often helps to disentangle thehost of interfering factors which confuse the issue inindustrial practice. Evidence, at first inconclusive,has been reinforced from different sources-for

example, the increase in rate of output on shortshifts, the beneficial influence of short rest pauses,the importance of high illumination in fine processes,the deleterious effects of high temperatures on workinvolving muscular effort, are among the conclusionswhich were tentatively made at first and as the resultof many investigations, gradually came to be accepted.The Board is steadily gathering and propagatingnew knowledge, and even more important, is showingthat improved conditions of work are beneficial aliketo employers and workers.

STEEL DENTURES.DURING the late war the shortage of rubber and

precious metals in Germany affected, among others,the dental profession, since the construction ofdentures involves either a vulcanised rubber or agold base. As a substitute for these materials thefirm of Krupp began to experiment with stainlesssteel as a denture base. The method soon passedbeyond the experimental stage, and before the endof the war dentures of stainless steel were beingmade on a considerable scale. Even now thatboth rubber and gold are freely procurable, steelis still being used in Germany to some extent,apparently with satisfactory results. In Englandexperiments have been chiefly directed towardsfinding a synthetic resin which could be colouredto resemble gum more closely than is possible withvulcanite, and these attempts have been so farsuccessful that it is hoped that vulcanite may soonbecome obsolete. The German investigations have,however, stimulated some preliminary trials of steelin this country, and Mr. A. C. Hutchinson, in theBritish Dental Journal for May 15th, records someexperiments carried out in the Manchester DentalHospital with the cooperation of Messrs. Firth andSons, of Sheffield. It appears that Krupp’s use fordentures a rust-proof steel belonging to what istermed the VA group, which has a high resistance tocorrosion even when soft. It contains 20 per cent.of chromium and a medium content of nickel. Adenture made of this material is only half the weightof a gold plate of the same thickness, and in order toensure equal strength the gold denture would haveto be twice as thick, and would weigh four times asmuch. Mr. Hutchinson experimented with Firth’sStaybrite silver steel and found it possible to hammerand swage the material into dental plates. Soldering,on the other hand, presented great difficulties and,so far, the search for a suitable flux has not beenwholly successful ; but it was found possible toattach teeth to a steel plate by means of vulcanite,and the attachment appeared perfect. The work isstill in the experimental stage in this country, andthe production of dentures which are satisfactoryin the mouth is still some way off, though there seemsto be no reason why the German results should notbe repeated here. We understand that in Germanythe process is complex, involving a technique notpossible in a dental workshop, and that the actualswaging of the steel is carried out by Krupp’s tomodels supplied by dentists. Nevertheless the methodhas distinct possibilities and we hope that Mr.Hutchinson will continue so promising an experiment.

SPASM OF THE PYLORUS IN INFANTS.ONE effect of the introduction of Rammstedt’s

operation for hypertrophic stenosis of the pylorus ininfants has been that a distinction is drawn betweencases in which there is a palpable pyloric tumour andthose in which there is not. With an experienced andcareful observer it is safe to say that if a tumourcannot be felt after several examinations, and visiblegastric peristalsis is well marked, the case is probablyone of pyloric spasm, for which operation is contra-