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mucosœ and muscularis at the margin of the ulcer.These are discussed at some length in connexion withcontrol groups of 249 peptic ulcers and 100 carcino-mata of the intestine, and the conclusion is reachedthat fusion of the muscularis mucosae and muscularisat the edge of the ulcer is as valuable a sign in thediagnosis of ulcer-cancer as the demonstration oftubercle bacilli in the diagnosis of tuberculosis. Appli-cation of this test to a series of 307 stomachs removedby operation at St. Mary’s Hospital shows that3-75 per cent. of gastric ulcers had malignant change,and that 13, per cent. of the cancers showed evidenceof previous peptic ulceration. These figures are inremarkable agreement with those given by Prof. M. J.Stewart in his Croonian lectures,2 viz., 6.1 and 15.6respectively, although he used somewhat differentcriteria. The outcome of this investigation is two-fold. The risk of cancer developing in a peptic ulcer,although small, is evidently not negligible, while, onthe other hand, it is clear that the aetiology of mostcases of gastric cancer still awaits discovery.

LEEUWENHOEK’S "LITTLE ANIMALS"

A SPLENDID monument of piety and scholarship ispublished 3 on the 300th birthday of the man whomay be described as the " discoverer " of protozoaand bacteria as fairly as anybody may be said tohave " discovered " anything. Leeuwenhoek (pro-nounced " laywenhook ") was born on Oct. 24th,1632, at Delft, where he spent his life, by businessa draper and a man of some civic consequence in atown which knew of other than material values. Hemarried in 1654, the year in which a gigantic gun-powder explosion killed the Fabritius who paintedthe incomparable goldfinch ; he was contemporarywith Vermeer and his widow’s trustee, and he maywell have known the girl whose head we all likeso much. When exactly he perfected his skill in

grinding lenses and made glasses of a magnificationand definition hitherto unknown is not recorded,but in 1673 de Graaf (of the follicles) wrote to thesecretary of the Royal Society of London to say thathis friend and fellow-townsman, "Leewenhoeck,"had made some exceptional microscopes, and encloseda letter by him giving an account of some of thethings he had seen with them. From that timeLeeuwenhoek continued to send letters to the RoyalSociety (of which he became a fellow in 1680), thelast from his deathbed in 1723, in which he detailedthe results of his insatiable curiosity. With his newinstruments he looked at everything about him-he even watched gunpowder explode-and made newdiscoveries about them all-blood corpuscles, the

capillary circulation, spermatozoa, the budding of thehydra, the structure of muscles, and more particularlymicrobes, of which he demonstrated the existenceand abundance, though there seems to be no evidencethat he suspected them of being of any great import-ance in the world. From these letters, going backwith infinite pains to the original manuscripts as faras may be, Mr. Dobell has extracted and translatedwhat refers to protozoa and bacteria, and has care-fully annotated the descriptions and identified theorganisms. Leeuwenhoek’s microscopes were simplelenses which magnified at the most about 250 times,and how he managed to see what he undoubtedlydid see has always been something of a mystery, forhe kept the details of his methods to himself ; Mr.

2 THE LANCET, 1931, ii., 620.3 Antony van Leeuwenhoek and his " little animals." By

Clifford Dobell, F.R.S. London : John Bale, Sons andDanielsson. 1932. Pp. 435. 31s. 6d.

Dobell makes the likely surmise that he had hit upon.some trick of dark-ground illumination. He also"

exposes the abundant sins, negligencies, and ignorances-of previous translators and commentators, though heis, we think, rather hard (p. 351) on the perfectlyrecognisable medallion which used to appear on the.cover of Abstracts of Bacteriology-no longer current,.as he says, for that journal came to an end in 1926,.though the " caricature " still adorns the Journal ofBacteriology and reminds us of a great man for thegood of our souls. It is all so well done that ouronly regret is that it has not yet been possible to-treat the rest of Leeuwenhoek’s writings in the sameway. We sincerely hope that Mr. Dobell will long beable to maintain the habits of unremitting industryof which he tells us in the preface, and will take a.large part in the preparation of the Opera Omniawhich is contemplated by the Dutch committee.The form of the present instalment, if we may so.regard it, is hardly worthy of its matter.

VISUAL ACUITY

IN a report to the Medical Research Council,>>R. J. Lythgoe and Dorothy E. Corkill deal with therelation between visual acuity and illumination..In spite of many results to the contrary the viewis still widely held that visual acuity comes to amaximum at an illumination of 3-4-foot candles.Artificial illuminants giving more than 10-foot candlesare sometimes condemned, but values of more than100 times this figure are commonly met with out-of-doors, and there is no doubt that acuity is consider-ably better under these high illuminations, thoughthe author’s graphs demonstrate that the rate of

improvement is a constantly diminishing one atilluminations higher than 100-foot candles. More-over, high values of visual acuity are only obtainedwhen attention is paid to the illumination fallingon the peripheral retina. In a room that is darkthe increase of acuity at high illuminations of thetest object is not obtained, but only when thesurrounds are 1/100 to 1/10 as bright as the testobject. The improvement in acuity is due partlyto the constriction of the pupil and partly to anincrease in retinal sensitivity. Unless the surroundsare kept adequately illuminated there may even bea falling off in visual acuity when the illumination ofthe test object exceeds a certain value.The effect of glare on visual acuity was also

investigated-i.e., the effect produced by theillumina-tion of a single spot in the neighbourhood of thetest object. When the surrounds are dark, glaremay even have the effect of increasing visual acuity, but in an adequately illuminated room the introduc-tion of glare causes a fall in visual acuity which isnot due to the pupil and is not abolished by artificialpupils. These results, as will be seen, have a directbearing on the routine work of eye-testing. Anotherimportant aspect of the subject is dark adapta-tion. The performance of a ship’s outlook is inade-quate, either if insufficient time is occupied indark adaptation or if there are bright lights in the’field of vision. For accurate and rapid testingof visual acuity it is important to use illuminationsover 25-foot candles in a moderately light room.Commercial test-types, it is added, usually containerrors of more than 10 per cent. in their dimensions.The physiological implications of this study are

interesting. The increase in sensitivity of the retina1 Committee on the Physiology of Vision. H.M. Stationery

Office. 1s. 6d.

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during dark adaptation is so great that there is often2. tendency to ignore other aspects of visual adapta-tion. A twofold apparatus connected respectivelywith the rods and the cones is generally believedto account for the phenomenon, but it is also truethat the sensitivity of the fovea (where there are onlycones) seems to be increased by peripheral illumina-tion up to a certain value, beyond which a depressionsets in.

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THE PROPER USE OF SANATORIA

IN an address to the December meeting of theTuberculosis Association, Dr. H. Batty Shaw spokevery strongly of the harm done by exercise in casesof active tuberculosis. Rest of the lung, he said, hadbeen shown to be undoubtedly the best form oftreatment, and yet patients treated in a sanatoriummight be encouraged to go for walks of several milesor to play golf, or allowed to work at carpentry orgardening. Rest being the most effective form oftreatment, the sooner it was applied, the more

completely it was applied, and the longer it was

applied, the better. Collapse therapy, carried outimmediately the diagnosis was made, instead of whensanatorium treatment had been tried and had failed,would effect a considerable reduction in the numberof cases of chronic pulmonary tuberculosis. Whatwas most needed by each county, Dr. Batty Shawwent on to say, was not sanatoria buried in thecountry, but more hospitals in busy urban centresadministered by tuberculosis officers. The patientsadmitted into these "tuberculosis institutes," as hepreferred to call them, should be divided into threegroups : (1) those admitted for closer observation ;2) those admitted for the commencement of treat-ment by medical or, if necessary, by surgical collapseof the lungs ; and (3) those admitted for symptomatictreatment who could not be adequately nursed andaccommodated in their own homes. The sanatoriashould become convalescent homes, requiring less.expensive maintenance because the patients wouldonly stay for a few weeks and would’be up and aboutduring their residence. A scheme of this kind would,he claimed, cost but a fraction of the sums now being.expended, and materially reduce the mortality from.tuberculosis. ____

THE FLYING DOCTOR IN AUSTRALIA

THE Australian’s own name for the two millionsquare miles of pastureland which lie in the interiorof the continent is the " outback country," and it is.an apt description of that isolated district. The.fertility of the soil is counterbalanced by the uncer-tainty of the rainfall, which makes agriculture evenmore of a gamble than usual; it has attracted fewsettlers, and these live scattered over the countrysidein widely distant farms. One of the greatest disad-vantages imposed by such life is the absence of medicalskill and advice in times of illness, and the impossibility- of speedy and comfortable conveyance of the sickto civilisation. Dr. W. D. Walker, in a lecture whichhe gave at the London School of Hygiene and TropicalMedicine on Dec. 8th, described the work of the Rev..John Flynn, superintendent of the Australian InlandMission, in organising medical services for this area.Some 20 years ago Mr. Flynn began to form the chainof 13 hospitals which now have been set up, each-with two well-qualified nurses. But it was not till-wireless and aviation had developed that Mr. Flynnfound the appropriate means whereby adequatemedical care may be provided for a scanty population- distributed over an immense tract of country. In

May, 1928, Dr. K. St. Vincent Welch, the first " flyingdoctor," set up practice at Cloncurry in Queensland.With his aeroplane he could attend patients withinan area of a quarter of a million square miles, andsoon wireless transmitters extended the range of his

consulting-room to 600 miles. The sets were bothsimple and efficient ; the power for the wirelesstransmitters was derived from small foot-pedalledgenerators, and frontier transmitters were set up atisolated places which had no other means of communi-cation. At first home operators had to learn Morse,but recent improvements have now made it possiblefor messages to be sent in Morse by tapping anautomatic typewriter. The operator at the centretranslates the message, and the doctor sends hisprescription direct by wireless telephone. Duringthe first year of the service Dr. Welch flew 20,000miles, and attended 255 patients in 26 centres, allwithout a single mishap. The solid achievement thatthese figures represent has grown steadily with everyyear. ____

PUBLIC ANALYSTS

SURE knowledge, critical acumen, ripe judgment,and a kind heart form the equipment which Dr.Dyer brings to the difficult task of telling the tale ofhow a profession grew out of a very heterogeneousgroup of pioneers. When the first Food and DrugsActs came into force, as a result of the exertions ofThomas Wakley, founder of THE LANCET, therewas no coherent profession of chemistry. A fewmedical men of outstanding ability and real scientificfeeling, others who were anything but scientific,some chemists with a general training, and somemere hangers-on, formed the first public analysts.Divided among themselves, with duties requiring fortheir fulfilment knowledge which no one yet possessed,subject to the overruling of a government depart-ment the members of which were no better qualifiedthan themselves, and feeling it their duty to keeptheir methods secret, they had a very difficult time.Fortunately they clung together and formed them-selves into a society which was at once a researchassociation and a professional union. The historyof the Society of Public Analysts from 1875 to 1925was not an easy thing to write,1 at least in a mannerwhich would do justice to the steady aim of its leadersto advance the science and profession of analyticalchemistry, especially as applied to food and medicines.From 1875 onward to the present time Dr. Dyerhas not only taken a prominent part in all the activitiesof this society, but has watched in a singularlydetached way the men engaged in these activities,never blinding himself to their weaknesses and neverfailing to appreciate the honest and good motiveswhich led to their mistakes. There is no unkindlyword nor one of fulsome praise in the 72 pages ofreminiscences. The list of presidents of the societyincludes names well known in medicine : Alfred Hill,Matthew Adams, Thomas Stevenson, and CharlesCameron, besides others who are better known as

chemists pure and simple : August Dupre, who withhis brother-in-law J. L. W. Thudichum, wrote so

learnedly on wines, and who did excellent pioneerwork on water analysis ; Alfred Allen, whose " Com-mercial Organic Analysis " is still a well-knownclassic ; the debonair and learned Alfred ChastonChapman, who has died since this book was compiled ;and other outstanding analysts. The society has

always been associated with the Analyst which-1 Fifty Years of the Society of Public Analysts. By Bernard

Dyer, D.Sc., F.I.C., and C. Ainsworth Mitchell, M.A., D.Sc.Cambridge: Heffer and Sons. 1932. Pp. 278. 12s. 6d.