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THE DEATH-RATE OF NORWEGIAN DOCTORS.

MEDICAL men in Norway die before theirtime, speaking generally. At the age of 30their expectation of life is some ten years lessthan that of the average Norwegian man. Lessthan 8 per cent. of them pass the age of 80,while the corresponding figure for Norwegianmales over 30 is nearly 25 per cent. Theseand other statements are set out in a recentarticle by Dr. 1. Kobro,1 and are based on statisticsrelating to 1015 Norwegian practitioners of medi-cine dying between the years 1800 and 1908. Of

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those dying before the age of 50, over a quartersuccumbed to acute infectious disorders (excludingtuberculosis) that were no doubt picked up in theperformance of their professional duties, and othersdied in consequence of the accidents of countrypractice. Among the older medical men malignantdisease and apoplexy accounted for an unduly highpercentage of deaths. Dr. Kobro points out that hisfigures deal with but a relatively small number ofcases, and that the diagnoses of the causes of deathare naturally not entirely to be trusted. Hisstatistics are set out in tabular form, however, andit is plain that he has proved the relative shortnessof the Norwegian doctors’ lives.

THE OCCURRENCE OF CARRIERS OF DISEASE-PRODUCING PNEUMOCOCCUS.

IT is known that there exist in the mouths ofnormal persons as well as of patients sufferingfrom pneumonia definite pneumococci. Dr. A. R.Dochez and Dr. O. T. Avery have shown that thereare four definite types of pneumococcus; that threeof these types are met with in patients sufferingfrom pneumonia, and are together responsible for75 per cent. of these cases, whilst the fourth type(Type IV.) is also met with but is only found in theremaining 25 per cent.; in these cases the diseaseis found to be usually less severe, and what isimportant is that this fourth type of pneumococcusis hardly distinguishable from that to be found inthe healthy person’s mouth. Since the highlyvirulent forms (Types 1., II., and III.) are alwaysassociated with disease, and only occur in otherconditions under circumstances to be imme-

diately explained, the evidence is strong thatin the spread of lobar pneumonia the diseaseis, in a majority of instances, transmittedfrom one individual to another. The same writersrecently in the Journal of Experimental Medicinegive evidence which strongly suggests that personsclosely associated with individuals suffering frompneumonia in a large percentage of instancesharbour in their mouths pneumococci of the sametype as those causing the disease, that suchorganisms are not found in the mouths of normalindividuals not exposed to pneumonia, and that theconsiderable period of time during which theseorganisms are carried may in part account forthe sporadic occurrence of individual cases of

pneumonia. An additional means of transmissionis also afforded by the recovered individual.Thirty-two cases of pneumonia were studied. Theorganisms were observed in the case itself andcompared with those, if present, found amongstthe immediately surrounding nurses or relations.Amongst these associates it was found that therewere 13, or 40’6 per cent., who harboured

1 Tidsskrift for den Norske Laegeforening, 1915, vol. xxxv., p. 873.

the pneumococcus (Types I. or II.) of the sametype as that found in the patient. The

average duration of this " carrying state" " was

23 days, but the figure is probably too low. Aseries of 113 normal people were examined for thepresence and type of pneumococcus. Pneumo-coccus was found in 58’4 per cent. Of these,however, only 9’6 per cent. were of the disease-

producing Types 1., II., and III., and significantlyenough, all these cases were in individuals who,had been closely associated with cases of lobarpneumonia. Compared to this type incidence innormal people, in cases of lobar pneumonia thehighly pathogenic types were present in 77’2 percent. This is strong evidence that specific typesof pneumococci are mainly responsible for theproduction of lobar pneumonia. If these findingsare generally confirmed it ought to open up a.

rational prophylaxis against this dread diseaseby suitable measures directed towards the patientand his attendants, these being potential carriersof the pathogenic pneumococci.

AN ELECTRIC INTERRUPTER FOR ALTERNATINGCURRENT.

I WHEN an alternating current is used to work a,coil for the production of X rays, one of the chiefproblems that presents itself is the choice of aninterrupter. The use of an alternating current isoften obligatory owing to the fact that the distribu-tion of electric energy in towns is effected by meansof such a current, and small plants, if transportable,are not generally furnished with the complexdynamo motors necessary for the local transforma-tion of the alternating current into a continuousone. The ideal solution of the problem has untilnow been found in the turbine interrupter workedby a synchronous motor which interrupts thecurrent at the moment when it reaches its maxi.mum intensity. Such interrupters are, however,somewhat costly, and their use and maintenancenot very easy, so that it becomes necessary to

have recourse to the electrolytic interrupterin spite of the difficulties that its use presentswith the alternating current. Those who are

interested in the practical aspect of the questionwill find a communication by Dr. G. C. Trabacchiin Il Policlinico (Practical Section, August 22nd,1915) describing some improvements effected byhim in the electrolytic interrupter. The essentialdefects of such instruments are principally two : -.(1) the platinum point becomes rapidly worn outfrom acting as cathode for half the time; and(2) during the semi-period in which it is cathodeand which may be called the " inverse semi-period," interruptions occur, usually irregular,which, more than the closures taking place inthe " effective semi-period," induce currents whichare damaging to the tube by causing rapidmetallisation and hardening. The first defect isusually obviated by substituting for the platinumpoint one of iron, which can be renewed fromtime to time at a small cost, while saline solu-tion takes the place of sulphuric acid. To elimi-nate the second defect variously placed valves areput between the coil and the tube to absorbirregularly induced currents. There alwaysremains, however, the difficulty of finding theconditions of good working according to the auto-induction of the coil and of the hardness of thetube employed. By using an aluminium instead