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the dry powder extinguishers was found to bebicarbonate of soda. It may be remembered thatwe reported in THE LANCET that the BritishFire Prevention Committee recommended theuse of a mixture of bicarbonate of soda and saw-dust for the extinction of small petrol fires. Inthis case, however, the use of sawdust appeared tobe effective because it floats on the top of the

petrol so to an extent excluding the air and

smothering the fire. The bicarbonate of soda, itwas added in the report, had certain advantages,but its use was not regarded as essential.

INJECTION OF THE GASSERIAN GANGLION FOR TIC DOULOUREUX.

IN the Medical CLinics of Chicago for JanuaryDr. Ralph C. Hamill, of the Cook County Hospital,has published the record of a case of trigeminalneuralgia successfully treated by the injection ofthe Gasserian ganglion with alcohol. The patientwas an Italian labourer, aged 37, whose illness hadbeen of some ten years’ duration. Paroxysms ofpain occurred at very frequent intervals, runningfrom the inner canthus of the left eye down intothe left upper bicuspids. This pain was describedas consisting of lightning-like jabs of tearing,wrenching, stabbing pain, coming on with full

intensity, and lasting from a few moments to threeminutes. Swallowing, talking, chewing, shaving,&c., would all precipitate a paroxysm. On objectiveexamination no signs of organic disease could bedetected, and there was no evidence of arterio-sclerosis. Tic douloureux is a well-known clinicalcondition for which no adequate pathology has everbeen demonstrated, and its etiology is obscure. Wheresome definite local condition causes the pain thereis usually a more or less constant dull ache apartfrom the paroxysms, whereas in so-called idiopathictrigeminal neuralgia between the paroxysms thepatient is often entirely free from pain. Theadministration of various sedatives having provedunsatisfactory, Dr. Hamill injected the Gasserianganglion with 20 minims of the following solution :alcohol 3t drachms, cocaine 1 grain, water to halfan ounce. The point selected for the injection was2 cm. below the zygoma and 2t cm. anterior to theexternal auditory meatus. When the puncture ismade at this point it is necessary to have thepatient open his mouth as widely as possible,in order that the needle may clear the coronoid

process of the inferior maxilla. The needle ispointed upwards at an angle of about 60°to the plane of the face and slightly backward.At about 4 cm. in from the surface boneis encountered, the pterygoid plate; by slightlywithdrawing the point of the needle, changing itsdirection rather more backward, and elevating itsomewhat, the operator gradually feels his waywith the needle-point past the edge of the pterygoidplate to the base of the skull, just lateral to theforamen ovale. If the point is then inclinedslightly downwards and advanced, sudden painshould be felt in the distribution of the inferiordivision of the trigeminal-viz., in the lower jaw,cheek, lip, or tongue. If the needle is now advancedanother ½ cm. pain will be felt in the other branchesof the fifth. The syringe is then connected to theneedle and a few minims of the alcohol mixture isinjected. Immediately the patient complains of asensation " as if thousands of little darts or needleshad shot through the corresponding side of theface." Assured by this sign, the physician can then

inject a further ½ to 3/4 c.c., whereupon analgesiaappears throughout the distribution of the nerve.It is advisable to shield the corresponding eyeduring the first 24 hours following the injection, oreven to suture the lids together. Dr. WilfredHarris, however, has shown that corneal ulcerationmay be avoided by stopping short of total anaas-thesia ; the good effects are just as lasting from thepoint of view of relief from the pain.

THE METROPOLITAN WATER-SUPPLY.

THE report on the condition of the metropolitanwater-supply during the month of January by theWater Examiner appointed under the MetropolisWater Act was issued last week. It is the briefestdocument so far issued by this authority; its sizeperhaps reflects the shortage of paper, which isnow seriously inconveniencing public bodies. Theusual information on the chemical and bacterio-

logical examinations, for which Dr. A. C. Houston,the Director of Water Examination, is responsible,is summarised by Mr. C. Perrin, and does not,as hitherto, appear separately. The tables con-

taining the chemical and bacteriological resultsare, however, appended. All the samples ofwater collected at the different works were clear,bright, and free from suspended matter. Theresults of chemical examination showed that the rawwaters of the New River, the Lee, and the Thamesimproved in quality as judged by the albuminoidnitrogen, permanganate, turbidity, and colourtests. The filtered waters, however, deterioratedas judged by the albuminoid nitrogen (New Riverexcepted) and colour tests (with the exception ofNew River, East London, Sunbury, and Chelsea).Compared with the 1915 averages, the raw watersyielded results worse than their respective averagesas judged by the usual tests. The filtered watersyielded similarly worse results. All three rawwaters contained more bacteria than their respec-tive averages, while the filtered waters gave, gene-rally speaking, not unsatisfactory results. Whereas95’0, 100’0, and 65’0 per cent. of the samples of rawThames, Lee, and New River water respectivelycontained typical B. coli in one cubic centimetre(or less) of water, 83’4, 90’0. and 69’0 per cent. of thefiltered samples derived from the Thames, Lee, andNew River respectively contained no typical B. colieven in 100 times as much water examined-viz.,100 cubic centimetres. The rainfall was below theaverage mean for the month taken for the previous33 years. ____

ITALY’S chief balneary resort, Montecatini, sus-tained (writes our Rome correspondent) a severeloss last winter in the deaths, within a few weeksof each other, of its consulting head, Dr. Guido

Baccelli, and of its medical administrator, Dr.Pietro Grocco. Their vacant posts have just beensatisfactorily filled by the appointment in successionto Baccelli of Dr. Augusto Murri, the veteran pro-fessor of clinical medicine in the University ofBologna, known also, since Baccelli’s death, as

" Dean of the Medical Faculty " throughoutItaly ; and by the appointment, as Grocco’ssuccessor, of Dr. Giovanni Battista Queirolo,who has long held the clinical chair in the PisanSchool with conspicuous acceptance. One of themany sequelae expected to supervene on the closeof the present war will be, so far as Italy is con-cerned, a greatly increased development of herresources in balneary health resorts, with a view to

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retaining within her borders, and even to attractingfrom beyond them, much of the clientele hithertoclaimed (not always justly) by the German andAustro-Hungarian thermal

" cures." Montecatini

will be among the first of Italy’s balneary centresto receive the State encouragement in contempla-tion, and will enjoy, in the person of the SenatorDr. Queirolo, a Parliamentary representation andsupport which must redound to its interests in

every sense-medical, material, and administrative.

THE Highlands and Islands Medical ServiceBoard has issued under the title of a "SecondReport " the various explanatory documentsemanating from it up to the end of 1915.Several of these have been commented upon inTHE LANCET at the time of their appearance, andtheir republication in the form of a Blue-bookmakes the information contained in them acces-sible in a handy form. The lists of medical menand of their districts were originally sent out in theless convenient guise of posters. Draft forms,including one of an agreement between the Boardand a medical practitioner proposing to acceptservice under the Board, will be found among theappendices. The pamphlet can be obtained fromH.M. Stationery Office (Scottish Branch), Edinburgh,and the usual official publishing firms, or throughany bookseller. Its price is 3d. and its referencenumber Cd. 8246.

____

THE annual meeting of the British DentalAssociation is to be held in the hall of the RoyalSociety of Medicine on June 15th, 16th, and 17th.War injuries and gunshot fractures of the jaw willprincipally be dealt with, and an exhibition of

appliances has been arranged. The discussionopens at 2.30 P.M. on the 15th and at 10.30 A.M. onthe other days.

____

A COURSE of three lectures on Inherited Diseasein Children will be given by Dr. Mary Scharlieb at8 P.M. on Wednesdays, June 21st and 28th, andJuly 5th, in the Robert Barnes Hall, 1, Wimpole-street, W., by permission of the Royal Society ofMedicine. The lectures, which are given free towomen, will be illustrated by the epidiascope.

MEDICAL SICKNESS AND ACCIDENT SOCIETY.-The usual monthly meeting was held at the society’s offices,High Holborn, W.C., on May 19th, Dr. F. J. Allan being inthe chair. The accounts presented showed a falling off insickness in comparison with the same period last year, andthe experience is below the expectation for the four months-an unusual feature for the spring months. It was reportedthat further sums had been invested in Exchequer Bonds,making a total of 18,000 now invested in War Stocks sinceAugust, 1914. Applications were reported from membersfor annuities under the new table which is now registered bythe department and is accordingly open both to members andnon-members, and it is hoped will prove satisfactory anduseful to the profession generally. The society now transactsall the three benefits it was originally founded for and atrates that it would be hard to beat, and, as far as the sicknessis concerned, impossible. The committee have decided thatin future the society will pay the usual fee of 11 Is. for themedical examination of both new and additional proposals,the member to have the same right as hitherto of going towhom he peases for such examination unless otherwiseinstructed by the society. Membership is still open to thosetaking temporary commissions in the Royal Army MedicalCorps or the Navy within certain limits with regard toamounts, as so far the committee do not consider that thecasualties justify them in any way altering their previousdecision in this matter. No extra premiums are charged tomembers of the two forces mentioned. All applications forprospectuses and further information should be addressed tothe Secretary, Medical Sickness and Accident Society,300, High Holborn, W.C.

THE COCKROACH: ITS DESTRUCTIONAND DISPERSAL.

A COMPARISON OF INSECTICIDES AND METHODS.

BY JOSEPH J. H. HOLT, M.B., CH.B.VICT., D.P.H.

THE common cockroach (Periplaneta orientalis) is one ofthe most widely distributed, as well as one of the most

repulsive pests of civilisation. Its ubiquity and persistencedemonstrate alike its fecundity and power of adaptation.There is little record of investigations dealing with thenuisance. Mr. Frederick Laing, Assistant in Entomology,British Museum, informs me that most of the work on thesubject has been done in America, and some time ago.Much of the literature is old, because what has been donerecently has been little more than a revision or repetition.He kindly sent me a list of these publications with detailsof some of the remedies suggested. These I found of littlepractical value.For some two or three years I have been testing the action

of various substances. Preliminary investigations in refer-ence to general conditions gave some unexpected results.The cockroach is able to exist a long time without food orwater. One survived for 76 days in a Petri dish. It canlive with a very limited air-supply : in a very small stopperedbottle one lived for 3 days. Another survived submersion inwater for 20 minutes. The cockroach is an expert climber;. ra full-grown specimen can crawl up the vertical side of aglass bottle. Hence walls and ceilings offer no impedimentto it. It is not particular as to food-supply, eating prac-tically all kinds of organic matter, and also its own dead.It is, however, very clean in its habits, and carefully cleansesits own body. The cockroach is soon adversely affected bycontact with its own excreta. It prefers warm quarters,migrating till it finds them. Hence its predilection forkitchens on account of the constant warmth and available

food-supply. It dislikes light, but even constant exposureto it for long periods does not seem to harm it. It istherefore evident that architectural prevision cannot keepout the cockroach, nor domestic cleanliness starve it out.When once established, it must either be destroyed or drivenaway.In the following experiments the liquid volatile bodies were

used in a large, wide-mouthed, glass-stoppered bottle ofabout 1250 c.c. capacity. In most cases the quantity was1 drachm, and this, if volatilisation was complete, wouldgivea concentration of 3’2 per 1000. As, however, few of thebodies were completely volatile, the actual strength was con-siderably below this. The liquid was sprinkled on lint,which was then suspended in the bottle, but did not touchthe insects. Three to six insects were used, the time of deathin each case recorded, and the average noted. This averageis the one given in the tables. Most of the experiments wererepeated two or three times, some much oftener. Thedusting powders and food poisons were tested in shallowtrays, covered over with glass to prevent the cockroach fromescaping. Mechanical beetle-traps are of little use.. Theywere found to catch a very small proportion only, and afterthey become rusty inside the cockroaches can easily crawlout.The cockroach appears to be more resistant in autumn,

but no correction has been made in the tables for tempera-ture or season.

Results of Experiments on the Lethal Effect of VariousBodies on the Cockroach.

Volatile Bodies.Lethal Lethalin- I _ _ - -. - _

in-