APPARATUS FOR HYDROCYANIC FUMIGATION
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1223 bounded by the middle line, the right clavicle, and a point three finger-breadths above the right clavicle. Deep fluctuation was demonstrable, and incision of the swelling under a general anaesthetic yielded much offensive pus, which oozed out from under the sterno- mastoid muscle. The pus contained the Streptococcus pyogenes. The abscess cavity was as large as a hen’s egg and was situated between the right lateral iobe of the thyroid and the mid-cervical fascia. The patient made a slow but uneventful recovery. In distinguish- ing between this condition and suppurative thyroiditis more help may, in Prof. Clairmont’s opinion, be obtained from the history of the case than from the local examination before operation. APPARATUS FOR HYDROCYANIC FUMIGATION. THE fumigation of ships by hydrocyanic acid gas has been enthusiastically advocated and practised by the United States port health authorities, but the occurrence in America and in England of fatal accidents during the process has hitherto prevented the universal adoption of the method. Dr. G. R. Seager Thomas sets out in our present issue the post- mortem findings in two fatal cases which occurred last July at Southampton as an instalment of a more complete report. In the current number of the Journal of Hygiene Lieut.-Colonel W. Glen Liston, 1.M.S., and Mr. S. N. Gore compare the results of fumigation with HCN gas in a series of experiments on a ship using alternately the " dumping fixture" and Liston’s " cyanide fumigator." The character- istics of these two forms of apparatus may first be briefly described. The dumping fixture has been employed extensively in the United States. It consists of a barrel, to the upper edge of which one or two boxes are fixed on hinges. The barrel serves to hold a strong solution of H2SO4, while the boxes are filled with NaCN. The contents of the boxes can be tilted into the acid when desired by drawing upon cords adjusted for the purpose. The HCN gas is generated in this way. No special arrangement is made to distribute the gas, and the quantity evolved depends on the quantity and quality of the NaCN used. The concentration of the poison gas present in the space under treatment is not estimated at any stage in the process, and no means are provided for getting rid of the poison after it has accom- plished its work other than the natural ventilation existing on the ship. Liston’s cyanide fumigator is a more elaborate apparatus. The gas is generated in a closed box which can be placed in the open air. On the lid of the box a petrol motor, a fan, I and a chemical cabinet are fixed. The motor is capable of revolving the fan at a speed of 3600 revolutions per minute, and at this speed it can draw into the generating box, through an inlet pipe six inches in diameter, and deliver through an outlet pipe of the same diameter, 1200 cubic feet of air per minute at a pressure of six inches on a water gauge. The apparatus and chemicals required for generating, measuring, and testing the poison gas are contained in the chemical cabinet. The gas is evolved within the generating box by allowing a solution of sodium cyanide to mix with a solution of sulphuric acid on a mixing platform within the box. The quantity of poison gas evolved is regulated by the rate of flow of the two liquids upon the mixing platform ; this rate is controlled by two screw clamps fixed on the rubber tubing which conducts the fluids from the vessels in the chemical cabinet into the generating box. When the motor is working the poison gas is diluted as rapidly as it is generated with air drawn by the fan from the compartment under treatment through the inlet pipe connecting the generating box with the compartment. The poison gas, diluted in this way, is at once blown back by the fan along an outlet pipe connecting the fan and generating box with the compartment. The outlet pipe extends into the compartment for a considerable distance ; it is furnished with a number of branches of gradually decreasing diameter, so that the diluted gas is carried to the remotest parts of the compartment and delivered there at from eight to ten different points. These points may be selected on the various decks of the ship. The air and poison gas within the compartment are thus continuously circulated through the generating box, where more poison gas can be added at will up to the concentra- tion required to destroy rats, bugs, fleas, or other vermin. The concentration of poison gas in the air circulating through the machine can be estimated at any time by stopping the generation of the gas for a few minutes, while a measured volume of the air mixed with poison gas is taken either from the outlet pipe from the fan, or, by making special arrangements, from any part of the compartment under treatment. The apparatus and chemicals for this purpose are provided in the chemical cabinet fixed to the machine. Liston’s fumigator thus differs from the dumping fixture in that (1) the poison gas, on generation, is rapidly diluted with air, so that high concentrations are avoided ; (2) the evolution of the gas is con- stantly under control during the whole period of fumigation ; (3) the concentration of gas within the room can be estimated at any time ; (4) the distri- bution of gas in the compartment is rendered more rapid and even by mechanical means ; (5) the gas can be displaced by fresh air when its work is accom- plished, a system of artificial ventilation assisting the natural ventilation of the ship. The machines are portable and can be carried by two men. Each is equipped to deal with 60,000 cubic feet of space at one time, so that a number of machines or units are required for the fumigation of a ship ; the units should be used simultaneously, so that the whole ship is fumigated at one time. The period required for completing the process is from three to four hours. A port health officer should be provided with at least ten units or machines. The experiments detailed by the authors in their paper demonstrate the defects and dangers of the dumping fixture and the advantages, noted above, which are to be derived from the use of the fumigator. For instance, while 7 Ib. of sodium cyanide scarcely sufficed to kill all rats when the dumping fixture was employed, 6 lb. were sufficient to kill all rats with the fumigator. The use of the fumigator probably ensures greater safety, first because the poison gas is generated in the open air, secondly because its rapid dilution prevents the occurrence of pockets of poison gas in high concentrations. With the fumi- gator economy in the use of cyanide and acid effects a saving which goes far to cover the greater primary outlay and running expenses, as against the smaller cost and maintenance charges of the dumping fixture. On the grounds of safety and efficiency, therefore, it seems possible that Liston’s cyanide fumigator may replace the dumping fixture in the fumigation of ships by hydrocyanic acid gas. The publication of the complete report on the Southampton cases will be awaited with interest. ARSENOBENZOL AND THE SPIROCHÆTE. AN excellent survey of the position of arseno- benzol in the treatment of syphilis is contributed by Mr. Claude H. Mills to the April and May numbers of the British Journal of Dermatology and Syphilis. After considering the various methods of administering the drug and the points in its favour, the author discusses the limitations of the arsenobenzols in syphilis. He points out that the failure of arseno- benzol to cure cases of syphilis, in which some time has been allowed to elapse before treatment has commenced, is due to the fact that the Spirochœta pallida has a power of remaining latent in avascular retreats where arsenobenzol is unable to reach it. No matter what drugs may supersede those in present use, they will be faced with the same problem of penetration. Another important point upon which the author dwells is the variation with which indivi- dual cases presenting a clinical similarity with regard to duration of infection respond to a uniform course of arsenobenzol treatment. It is probable that the rate of excretion exerts an important influence, for, as Mr. Mills points out, the patient who eliminates a given dosage slowly does better clinically than a patient who excretes the same rapidly, although at the same time he is more likely to develop such collateral effects as dermatitis and jaundice. The slower he excretes the greater the chance of a large proportion of the injected dose being converted into spirochaeticidal derivative. Another point on which the paper lays emphasis is the dangerous nature of the relapses met with in cases that have been insuffi- ciently treated with arsenobenzol. These relapses
Transcript of APPARATUS FOR HYDROCYANIC FUMIGATION
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bounded by the middle line, the right clavicle, and apoint three finger-breadths above the right clavicle.Deep fluctuation was demonstrable, and incision of theswelling under a general anaesthetic yielded muchoffensive pus, which oozed out from under the sterno-mastoid muscle. The pus contained the Streptococcuspyogenes. The abscess cavity was as large as a hen’segg and was situated between the right lateral iobe ofthe thyroid and the mid-cervical fascia. The patientmade a slow but uneventful recovery. In distinguish-ing between this condition and suppurative thyroiditismore help may, in Prof. Clairmont’s opinion, beobtained from the history of the case than from thelocal examination before operation.
APPARATUS FOR HYDROCYANIC FUMIGATION.
THE fumigation of ships by hydrocyanic acid gashas been enthusiastically advocated and practised bythe United States port health authorities, but theoccurrence in America and in England of fatalaccidents during the process has hitherto preventedthe universal adoption of the method. Dr. G. R.Seager Thomas sets out in our present issue the post-mortem findings in two fatal cases which occurred lastJuly at Southampton as an instalment of a morecomplete report. In the current number of theJournal of Hygiene Lieut.-Colonel W. Glen Liston,1.M.S., and Mr. S. N. Gore compare the results offumigation with HCN gas in a series of experimentson a ship using alternately the " dumping fixture"and Liston’s " cyanide fumigator." The character-istics of these two forms of apparatus may first bebriefly described.The dumping fixture has been employed extensively in
the United States. It consists of a barrel, to the upperedge of which one or two boxes are fixed on hinges. Thebarrel serves to hold a strong solution of H2SO4, while theboxes are filled with NaCN. The contents of the boxescan be tilted into the acid when desired by drawing uponcords adjusted for the purpose. The HCN gas is generatedin this way. No special arrangement is made to distributethe gas, and the quantity evolved depends on the quantityand quality of the NaCN used. The concentration of thepoison gas present in the space under treatment is notestimated at any stage in the process, and no means areprovided for getting rid of the poison after it has accom-plished its work other than the natural ventilation existingon the ship.
Liston’s cyanide fumigator is a more elaborate apparatus.The gas is generated in a closed box which can be placed in the open air. On the lid of the box a petrol motor, a fan, Iand a chemical cabinet are fixed. The motor is capable of revolving the fan at a speed of 3600 revolutions per minute,and at this speed it can draw into the generating box,through an inlet pipe six inches in diameter, and deliverthrough an outlet pipe of the same diameter, 1200 cubicfeet of air per minute at a pressure of six inches on a watergauge. The apparatus and chemicals required for generating,measuring, and testing the poison gas are contained inthe chemical cabinet. The gas is evolved within the
generating box by allowing a solution of sodium cyanide tomix with a solution of sulphuric acid on a mixing platformwithin the box. The quantity of poison gas evolved isregulated by the rate of flow of the two liquids upon themixing platform ; this rate is controlled by two screwclamps fixed on the rubber tubing which conducts thefluids from the vessels in the chemical cabinet into thegenerating box. When the motor is working the poisongas is diluted as rapidly as it is generated with air drawnby the fan from the compartment under treatment throughthe inlet pipe connecting the generating box with thecompartment. The poison gas, diluted in this way, is atonce blown back by the fan along an outlet pipe connectingthe fan and generating box with the compartment. Theoutlet pipe extends into the compartment for a considerabledistance ; it is furnished with a number of branches ofgradually decreasing diameter, so that the diluted gas iscarried to the remotest parts of the compartment anddelivered there at from eight to ten different points. Thesepoints may be selected on the various decks of the ship.The air and poison gas within the compartment are thuscontinuously circulated through the generating box, wheremore poison gas can be added at will up to the concentra-tion required to destroy rats, bugs, fleas, or other vermin.The concentration of poison gas in the air circulatingthrough the machine can be estimated at any time bystopping the generation of the gas for a few minutes, whilea measured volume of the air mixed with poison gas is
taken either from the outlet pipe from the fan, or, by makingspecial arrangements, from any part of the compartmentunder treatment. The apparatus and chemicals for thispurpose are provided in the chemical cabinet fixed to themachine.
Liston’s fumigator thus differs from the dumpingfixture in that (1) the poison gas, on generation, israpidly diluted with air, so that high concentrationsare avoided ; (2) the evolution of the gas is con-
stantly under control during the whole period offumigation ; (3) the concentration of gas within theroom can be estimated at any time ; (4) the distri-bution of gas in the compartment is rendered morerapid and even by mechanical means ; (5) the gascan be displaced by fresh air when its work is accom-plished, a system of artificial ventilation assistingthe natural ventilation of the ship. The machinesare portable and can be carried by two men. Eachis equipped to deal with 60,000 cubic feet of space atone time, so that a number of machines or units arerequired for the fumigation of a ship ; the unitsshould be used simultaneously, so that the wholeship is fumigated at one time. The period requiredfor completing the process is from three to four hours.A port health officer should be provided with at leastten units or machines.The experiments detailed by the authors in their
paper demonstrate the defects and dangers of thedumping fixture and the advantages, noted above,which are to be derived from the use of the fumigator.For instance, while 7 Ib. of sodium cyanide scarcelysufficed to kill all rats when the dumping fixturewas employed, 6 lb. were sufficient to kill all rats withthe fumigator. The use of the fumigator probablyensures greater safety, first because the poison gasis generated in the open air, secondly because itsrapid dilution prevents the occurrence of pockets ofpoison gas in high concentrations. With the fumi-gator economy in the use of cyanide and acid effectsa saving which goes far to cover the greater primaryoutlay and running expenses, as against the smallercost and maintenance charges of the dumping fixture.On the grounds of safety and efficiency, therefore,it seems possible that Liston’s cyanide fumigatormay replace the dumping fixture in the fumigationof ships by hydrocyanic acid gas. The publication ofthe complete report on the Southampton cases willbe awaited with interest.
ARSENOBENZOL AND THE SPIROCHÆTE.
AN excellent survey of the position of arseno-
benzol in the treatment of syphilis is contributed byMr. Claude H. Mills to the April and May numbersof the British Journal of Dermatology and Syphilis.After considering the various methods of administeringthe drug and the points in its favour, the authordiscusses the limitations of the arsenobenzols insyphilis. He points out that the failure of arseno-benzol to cure cases of syphilis, in which some timehas been allowed to elapse before treatment hascommenced, is due to the fact that the Spirochœtapallida has a power of remaining latent in avascularretreats where arsenobenzol is unable to reach it.No matter what drugs may supersede those in presentuse, they will be faced with the same problem ofpenetration. Another important point upon whichthe author dwells is the variation with which indivi-dual cases presenting a clinical similarity with regardto duration of infection respond to a uniform courseof arsenobenzol treatment. It is probable that therate of excretion exerts an important influence, for,as Mr. Mills points out, the patient who eliminatesa given dosage slowly does better clinically than apatient who excretes the same rapidly, although atthe same time he is more likely to develop suchcollateral effects as dermatitis and jaundice. Theslower he excretes the greater the chance of a largeproportion of the injected dose being converted intospirochaeticidal derivative. Another point on whichthe paper lays emphasis is the dangerous nature ofthe relapses met with in cases that have been insuffi-ciently treated with arsenobenzol. These relapses
