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Richard Paget, whose work was reviewed in thesecolumns a little over a year ago made extensiveexperiments with models to show that the vowel-sounds are musical tones of definite pitch, eachassociated with a pair of resonators formed by thethroat and mouth. Mr. G. O. Russell does not believethat " cavity tone " supplies the entire solution of theproblem, but thinks that the character of the surfacesand walls of the vocal cavities may be quite as

important. He has evolved a method of showingthe shape of the mouth and throat cavities, duringspeaking and singing, by means of X ray photo-graphs, using a marker to fix the median sagittalplane. The technique is not exactly described, but a,specially prepared thread is swallowed, which adheresto the mid-line of the tongue. It is difficult to seehow the mid-line can be marked out in this wayfor other parts of the cavity. On the numerouspictures given in the text the cavities have beenmarked out in white, which makes them easier to read,but which also necessarily raises some little elementof doubt. Mr. Russell also employs a " laryngo-periscope " of his own design, which enables theinterior of the larynx to be examined during phonation,and he provides some interesting photographstaken by this means ; a description and illustrationof the instrument would be of interest. His X raystudies comprise over 400 subjects and 3000 experi-ments ; this large mass of material has not yetbeen thoroughly digested, and the conclusions reachedcannot be considered final. He believes that theX ray pictures of the mouth and throat positionsduring production of the different vowels will be ofvalue, not only for the instruction of singers and inthe pronunciation of foreign languages, but in theteaching of deaf-mutes.

THE B.M.A. AT EASTBOURNE.

THE members of the British Medical Associationwere fortunate in having three days of anticyclonicweather between two periods of rain and cold. The

visitors, who took advantage of the many motortours provided for them, saw Sussex at its very best-poppies, thistles, rampion, and cornflower blazed inthe cultivated patches and a multitude of whatHudson called the " fairy flora of the downs "

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chequered the " wise turf " of Beachy Head andthe Seven Sisters. Brilliant sunshine favoured theCivic Garden-party in the beautiful grounds of

Folkington Manor on Thursday afternoon, andDevonshire Park provided a handsome setting for theevening receptions. Over 1100 members and guestsattended the President’s reception on Tuesdayevening, and nearly as many were to be seen at theCivic Receptions on the two subsequent evenings andat the Marquess of Hartington’s ball on Fridaynight. The annual general meeting was held in theTown Hall, where members robed for the procession toSt. Saviour’s Church for the official religious service.The sermon was preached by the Bishop of Chichester,and the service was preceded by a brief ceremony ofremembrance at the war memorial. An attractionto many visitors was the county cricket match,Somerset v. Sussex, which was conveniently timed totake place on the three days of the meeting, whilegolf competitions and tennis tournaments were

available for the strenuous. Medical missionary, andtemperance breakfasts were held as usual, and, inaddition, a Rotary luncheon, an Irish graduates’luncheon, a Masonic meeting, and a secretaries’

3 THE LANCET, 1930, i., 1074.

dinner claimed attendance from those suitably qualified..The popular lecture was delivered by Prof. F. T. G.-

Hobday on Some Diseases of Animals Communicable to,Man. The lecturer laid special stress on the regrettableexistence of tuberculous milk and the cvhaotic stateof the present regulations governing milk-productionand sale in this country. Some interesting films wereshown. The first was a record of the Ca,nadian meetinglast year ; the second was a "talkie" depictinglower segment Caesarean section as performed under-local anaesthesia by Dr. J. B. De Lee at the ChicagoLying-In Hospital. Dr. R. G. Canti showed toenthusiastic audiences his latest moving pictures ofmicroscopic life, and Petrolagar Laboratories showed"a series of films illustrating intestinal movements inanimals. A party of 100 people was entertained toa tour of the Level, dinner, and a concert by the.Hastings Division and Corporation on Fridayafternoon and evening, and other parties visited:neighbouring medical institutions.

RIVER POLLUTION—THE TEES SURVEY,

How is it that some rivers manage of themselves-.to purify the polluting liquids they receive ? z’ What.,quantities of different effluents can these rivers dealwith without destroying the conditions of self-purification ? Faced with such questions as these,the Water Pollution Research Board decided toexamine a typical river flowing through an industrialarea. It chose the Tees, which, in the 12 miles betweenStockton and the sea, takes not only the effluents ofmany factories, but also the untreated sewage ofThornaby, Stockton, Middlesbrough, and Billingham..A Tees Survey Committee began work in April, 1929,and the first instalment of information is now pub-lished.1 It deals with the hydrography of the tidaYriver ; complementary studies of the biological andchemical aspects will take another three years to"

complete. Meanwhile the Ministry of Agriculture-and Fisheries is examining the non-tidal reaches.One important result of the hydrographical survey

is our definite knowledge of the movement of currentsat different depths. At most of the observing stationsthe flood was found to run strongest at a depth below1 fathom ; the ebb, without exception, was strongeston the surface. From the surface to a depth of1 fathom the current ebbs longer than it floods. Below2 fathoms the flood runs for 6t hours or longer, and the-ebb is less than 6 hours. The maximum speed of theflood is at 1 or 2 fathoms’ depth, and not at thebottom, where friction against the river-bed retardsthe flow. We have to reckon with the different densityof fresh and salt water. We find the flood running:up-stream in the deeper layers, while the ebb is stillrunning out on the surface. Thus the broad inferenceappears that polluted matter will not readily escape-seawards unless it is in the surface layer. It is.

important, therefore, though apparently not easy,to obtain accurate measurements of the thickness ofthe upper layer. Useful evidence of silting, explicablewith better knowledge of the depth of the river-bedand the strength of the current, is available from theexperience of the Tees Conservancy dredging opera-tions. Indeed, the cooperation of local interests in thesurvey is a hopeful sign. When all the results of the:inquiry are published and coordinated, there shouldbe much to learn. In a preface to the report of the:hydrographical survey, Mr. H. T. Calvert, D.Sc., the:

1 Water Pollution Research : Technical Paper No. 2. Surveyof the River Tees, Part I.—Hydrographical. Published byH.M. Stationery Office. 5s. 6d. net.