1674 AERO-TRAFFIC.—MEDICINE AND THE COLONIAL OFFIOE.

of that of the soldier in particular, and we consider thatthe committee is cut off from a valuable source of informa-

tion by not containing a medical member. Has life in the

army kept reasonable pace with life outside it, or can it

with a due regard to order and discipline be still further

altered and improved for the soldier’s comfort and advan-

tage ? 7 Are the system of recruiting and the characterof the buildings set apart for that purpose of a kind

calculated to keep up the soldier’s self-respect ? 7 These

are specimens of the broad questions which the committeemust answer, while all proposals for reform must be pre-sented in subdued colours. For of one thing we may feelquite sure-namely, that the soldier desires to be treatedas a reasonably independent being in the nature and choiceof his own amusements and pursuits, and that he is justas keen as any other man to fight shy of all ill-judgedattempts to thrust upon him religious or moral instructionunawares.

Sir ALFRED KEOGH in his lucid and practical address atManchester particularly dwelt upon the necessity whichexists for some method of expansion of the Army MedicalService in the case of war by means of the civil medical

profession. He wants to see the Volunteer Medical Service

affiliated to the regular army, so that when war occurs

abroad it may take its part in mitigating the horrors of

warfare by tending to the sick and the wounded on the

field. Everybody desires the same, but members of the

medical profession, especially those who have done volunteerservice with the army in time of need, are perpetually madeto feel that the War Office does not wish to treat a Volunteer

Medical Service with any consideration. If Sir ALFRED

KEOGH can persuade or convince the War Minister that a

military medical reserve could be created with comparativeease by promising fair treatment to its constituents we mightfind in Mr. HALDANE’S promised declaration of a comprehen-sive army scheme a satisfactory proposal for dealing with anobvious reform.

Annotations."No quid nimis."

AERO-TRAFFIC.

THE aeroplane has come to be discussed so glibly as tosuggest that it is already un fait acceompli. There is, how-ever, abundant reason for thinking that the experimentalstages of aero-navigation have made a very fair beginningand as that is the case many people are naturally speculatingas to what are the prospects of future development whichwill bring the aeroplane within the sphere of everydayapplication. Improbable as such a consummation may

appear to be we cannot dismiss such an idea entirely fromour consideration when we reflect on the enormous advancesmade in motor traction. Only a few years ago the opinionthat motor traffic would attain any magnitude was scouted,and yet we are told that in spite of the large number ofmotor vehicles which we now see on the road the industryis still merely in embryo. So it may be with the aero-

motor as soon as a good working principle has beenestablished. The aeroplane is not simply a balloon but amachine propelled in any required direction-the humananalogue, in fact, of the bird in flight. It is interesting toask whether the new kind of locomotion is calculated to

bring fresh ills to the human race. Accidents apart, travel-

ling by aeroplane is calculated in some directions to be ahealthy mode of getting about from place to place. The

vehicle will rise above the impurities contained in the air ofthe streets and may even reach a level far removed from the

madding crowd of microbes. It is well known that on theearth’s surface at normal level we practically exist in a

sediment of bacteria, but as we rise above this level so thenumber of organisms sensibly diminishes until at last theycease to exist at all and the air is bacteriologically pure andsterile. The difference in this respect is even marked betweenthe ground floor and the top floor of an ordinary building.The air in the former case is rich in bacterial flora, whilein the latter their number is not only reduced but the

pathogenic members are frequently absent altogether. Ifwe were guided by this fact, therefore, we should standa much better chance of escaping bacterial invasion

by living on an elevated floor of a house rather thanon a floor near the level of the street. The bacterial

purity of high altitudes has been established by experi-ment. Chemically speaking also the upper strata of air arepurer than the lower and even in this regard a distinct tdifference in the quality is seen between the air of the

top and of the ground floor in favour of the former. The

impurities of the air at ground level are, of course, ex-

plained by the force of gravitation bearing the particles toearth. The aeroplane, it may be assumed, will ascend abovethis contaminated air and soar, it need not be at a verygreat height, yet nevertheless into regions of air purified bylight, ozone, and the process of sedimentation. All thissounds ideal, but, on the other hand, there will be a

diminution of pressure which may unfavourably affect theheart’s action, for the pulse-rate increases as atmosphericpressure is withdrawn, the secretions are diminished,while the evaporation from the skin and the lungs is de-

cidedly augmented. At extreme heights there are swellingof the veins and bleeding from the nose and there is

a sense of being unable to use the legs and the arms.The distressing symptoms of mountain sickness may even besimulated during a journey in an aeroplane. Doubtless,however, all these evils could be avoided by keeping theaeroplane as much as possible within certain limits of

elevation and at a uniform level. The aeroplane would atleast spare us from one serious nuisance of the motor-car,and that is its unfortunate habit of raising dense clouds ofdust. To some extent, too, it should be free from the

reproach of making distracting noises and possibly its sphereof action would be too remote to affect us by the dissemina-tion of offensive smells.

____

MEDICINE AND THE COLONIAL OFFICE.

WE have received through the courtesy of a distinguishedLondon teacher a note written to him by one of his latepupils from an address which we will give as simply "theBritish Central Africa Protectorate," inclosing a photographof a very interesting case of elephantiasis. The colonial

surgeon’s note upon the case is : " 210 ounces of clear fluidfrom one and 12 ounces of tarry fluid from the other sidewas the amount I measured. After removal of several poundsof greatly thickened and ulcerated scrotal tissue a veryrespectable result was obtained and the patient went off

home, 45 miles away, on foot, vowing eternal prayerson my behalf." Other passages in the letter would

hardly lead us to expect any good surgical resultsfrom the district where the operator resides. " Underthe new Government," he says, "it seems harder to

get grants for anything scientific than before. Itwill seem almost laughable to you that one operationof any importance exhausts the allowance of dressings&c., for a year pretty well. Things are doled oat like

1675

bowls of soup by a relief society. Occasionally one getshold of a case of some interest, but then rarely are the neces-sary appliances at hand." The Colonial Office has now taken

over this Protectorate and it is generally believed that theColonial Office is more alive to medical needs and intereststhan is the Foreign Office. We are, therefore, very sorry tohear a statement made on the spot of so disappointing acharacter and hope that the writer has not quite appre-ciated the situation. The work thrown upon the Colonial

Office has been increased enormously during the last halfdozen years and it is inevitable that the pressure shouldbe felt more in some places under so wide a jurisdictionthan in others. We have every reason to believe that the

policy of using the developments of medicine as one of

the surest ways of making colonial rule useful, durable, andprofitable-a policy which owes much of its vigour to Mr.Chamberlain’s initiative-is thoroughly believed in by thepresent Government. The most tangible blessing that thealien occupier can bring to the’native inhabitant is increasedhealth. Again, the most practical way of insuring that thesupply of colonial servants should be good and that theimmigration should be regular of men able to benefit boththemselves and the country of their choice is to provide, asfar as possible, a medical service and measures of prophy-laxis against endemic disease. No one can fail to see thatthis is so, and we do not believe that the Colonial Office,which has now frankly recognised this principle, is likely tobe perverted from it.

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A NEW SYSTEM IN WIRELESS TELEGRAPHY.

A VERY important advance in wireless telegraphy andone which may have an important bearing on the use ofhigh-frequency currents in medicine appears to have beenmade by Mr. Valdemar Poulsen of Copenhagen. At a

demonstration of this system at the Queen’s Hall on

Nov. 27th by the inventor himself the essential differencebetween the existing system of wireless telegraphy and thatinvented by Mr. Poulsen was explained to be that the latteremploys continuous undamped waves while the former de-pends on the use of damped waves which die down very

rapidly from the moment of their inception. He com-

pares the waves generated by a sparking oscillator with thesound waves produced by a pistol shot and the continuouselectric waves to the waves of sound produced by a tuning forkin continuous vibration. If the latter is placed near a pianoonly the one string which has the same rate of vibration willrespond and give sound, the other strings remaining silent. Apistol shot, on the other hand, will make all the strings ofthe piano vibrate. A little consideration will show the greatsuperiority of the new method. Regular waves of equalamplitude will carry further for the power expended and,what is equally, if not more, important, only an instrumenttuned to the same frequency can receive a message trans-mitted by means of them, rendering interference with, or"tapping of, messages almost impossible. Many men ofscience have endeavoured to produce undamped waves suit-able for wireless telegraphy and the most nearly successfulexperiments were those in 1899 by Mr. Duddell, who

discovered that when an alternating circuit of suitable

capacity and self-induction is connected in parallel with anelectric arc fed by direct current, the arc will undercertain conditions become musical and simultaneously thereis produced in the shunt circuit an alternating currenthaving the same rate of vibration as the rate producedby the arc. In this way Mr. Duddell obtained oscilla-tions up to 30,000 or 40,000 per second, but for the

purposes of wireless telegraphy this frequency is too lowand the energy is too feeble. Mr. Poulsen employs whatis really a modification of Mr. Duddell’s device, in that hesurrounds the arc with an atmosphere composed of, or con-taining, hydrogen. By so doing a far higher frequency is

obtained, amounting to a million or more vibrations persecond. In the instruments shown the arc is placed in astrong magnetic field produced by two electro-magnetsplaced in series with the arc. Under this condition the

potential difference between the electrodes becomes verygreat in proportion to the length of the arc-440 volts maycorrespond to a length of arc of three millimetres and agreat gain in efficiency is obtained for the whole system.The arc is as nearly as possible silent, due no doubt to theinability of the human auditory system to render such rapidvibrations as sound. Mr. Poulsen then showed some verypretty resonance experiments with his generators and after-wards proceeded to explain how he had utilised them forwireless telegraphy. The sharpness of tuning with whichstations on this system may be worked without mutualinterference is about 1 per cent. With a somewhat im-

provised installation of three receivers in connexion withthe same antenna three different telegrams were receivedsimultaneously without any mutual interference. Recentlywith a power of about one kilowatt, perfect communicationduring day and night has been established between Copen-hagen and North Shields, a distance of 530 miles, 150 ofwhich are overland, with a height of mast of only 100 feet,and from this Mr. Poulsen is convinced that transatlanticcommunication should be readily obtained with a power often kilowatts. Mr. Poulsen considers that these undampedand continuous wave trains present very great possibilitiesin relation to wireless telephony.

THE DISINFECTION OF RAILWAY CARRIAGESWITH FORMALDEHYDE GAS.

IN a recent article on the Sanitation and Hygiene of Rail-way Carriages reference was made to the fact that experi-ments were being conducted in the United States with aview of determining a satisfactory method of disinfectingrailway carriages. The results of these experiments havenow been published,2 in so far as concerns the employmentof formaldehyde gas as a disinfectant. The various methods

of producing the gas were referred to in a recent annota-tion,3 wherein were indicated the essential conditionsfor obtaining the gas in an active state. The author ofthe present bulletin, Mr. Thomas B. McClintic, deals veryfully with the relative merits of these methods, especiallyas regards their value in the disinfection of railwaycars, a number of which were placed at his disposal bythe Pullman Company. The cars were selected at random,and before starting the experiments all the berths were letdown, the inside doors were opened, and the windows and theventilators were closed. The cars contained on an average4500 cubic feet of air space. It was found that in coldweather very little formaldehyde gas was produced owing to

the polymerisation of the gas at temperatures below 600 F.A small quantity of the gas is, however, efficient for surfacedisinfection, provided the temperature and humidity arehigh. A large quantity assists penetration of the gas,as also do high temperatures and humidity, but even

then the penetrating power of formaldehyde is so

limited that it should not be used for disinfectingarticles requiring any marked degree of penetration.Under the conditions specified the quantity of formaldehydemay vary from 200 to 500 cubic centimetres per 1000 cubicfeet of air space, a larger quantity than is required forordinary rooms owing to the very rapid leakage of the gasin railway cars through ventilators and other openings. The

length of exposure depends upon circumstances. Underfavourable conditions two hours are usually sufficient, thoughthe experiments showed that in surface disinfection with

1 THE LANCET, Dec. 1st. 1906, p. 1534.2 Bulletin No. 27, Hyg. Lab., U.S. Public Health and Marine Hospital

Service, Washington, 1906, pp. 112.3 THE LANCET, Sept. 29th, 1906, p. 890.