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Elastic fibres will penetrate a scar, epitheliumregenerates, many large gastric ulcers heal with scmuch reconstitution of the stomach wall that theiiformer situation becomes almost impossible to per-ceive post mortem. In other mammals largeportions of muscular tissue have been removed andthe muscles have regained their normal size. Motornerves which have been divided and implanted into

muscle have been observed to form new end-plates.The parietal loculi of the common bile-duct havehypertrophied after cholecystectomy to the extentof giving the animal a new gall-bladder as far asfunction goes. It cannot be denied that regenera-tion will take place in the kidneys. May wenot still hope that, as the result of some new

discovery, the fibrous barrier we now obtain inthe most aseptic wound will be reduced to a

vanishing-point, and ultimately cease to be a

barrier at all ?Meanwhile it is all to the good that the limita-

tions of surgery in its present stage of develop-ment should be fully realised. The prevalenttendency to restrict the extent of surgical inter-vention is also good, for the safety and ease withwhich the surgeon has learnt to remove organs or

QL large portions of them has sometimes led to tooD radical an outlook. New conceptions arising fromr more intimate knowledge of disease have restricted- the operations of surgery in many septic affectionsB such as acute osteomyelitis, cellulitis, carbuncle.1 We are entering, in Lord MoYNiHAN’s words, the erar of physiological repair by the craft of surgery.) Diligent search is being made to substitute some. method less radical than cholecystectomy or partial3 gastrectomy for cholecystitis or gastric ulcer. It isb in such studies that surgery advances and technique becomes finer, so that it may be used to greater. advantage on the fewer occasions when inter-; vention is necessary-witness especially the

7 progress in thoracic and cranial surgery. In thefuture no doubt the number of operations will lessen,, while the field of surgery will enlarge so as to includet what are now regarded as medical diseases. Itmay be that the present-day distinction betweenphysician and surgeon will disappear, and oneindividual will combine the knowledge and technicalskill of both, to the great benefit of the healing art.In neurology this has already happened. In thecase of the organs of special sense it has alwaysexisted.

ANNOTATIONS

THE EASTMAN DENTAL CLINIC.

THE opening of the Eastman Dental Clinic on

Wednesday of last week is an important event in therecord of the efforts made to provide for the dentalneeds of the children of London. For a long timethe only institutions available for the care of children’steeth other than extractions were the dental hospitals,and if time and distance had not limited the atten-dance they would have been overcrowded. Theinstit .tion of a large number of clinics in Londonand its suburbs by the London County Council hasmade conservative dentistry accessible to largenumbers of children, but as the scheme is far frombeing comprehensive or complete, the importantwork of treatment of defective growth of the jawsand abnormalities in position of the teeth is scarcelyattempted, and these conditions, together withthe treatment of diseases of the gums and somesurgical affections of the jaws, form a very valuablepart of the work of the special dental hospital. Mr.Eastman’s object is to demonstrate, in a particulararea, the beneficial effects on health of thorough andcomplete preventive and remedial treatment of themouth and teeth from the earliest years. For thispurpose the sumptuous building and equipmentgenerously provided by Mr. Eastman are more thanadequate, and the maintenance has been guaranteedby Lord Riddell and Sir Albert Levy, the chairmanand honorary treasurer of the Royal Free Hospital,which the new building adjoins, and with which it isclosely associated as regards management andcontact. The orthodontic department is to be a

special feature, and will go far to meet a growingdemand for the treatment of the various forms ofabnormal jaw development, which are more intimatelyconnected with general health than is sometimesappreciated. Further possible developments of theclinic leap to the mind. Its association with theRoyal Free Hospital suggests a school for the trainingof women dentists, but for that purpose certainly

a child clientele only would not be adequate. Forthe training of dental nurses for employment inschool clinics throughout the country the institutionoffers good facilities and the employment of suchassistants to school dentists, with strict limitationof function, might well be more extensive than it is;but until the demand develops it would obviouslybe unwise to train more than can be easily absorbed.Another possibility is research, for which there willclearly be ample accommodation and.equipment, andprobably clinical material which it would be a pity towaste.

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RESEARCH ON THE COMMON COLD.

EARLY in 1928 the John J. Abel fund of$195,000was established in the medical school of Johns HopkinsUniversity for research into the cause of the commoncold. The first definite results from this research arereported in the current proceedings of the Societyfor Experimental Biology and Medicine.1 Healthyyoung women volunteers were secured for the experi-ment. They were isolated with great care fromall chance infection. The experiments, moreover,were carried out in the months of June and July, 1930,when the incidence of colds in Baltimore was at a lowlevel. Nasopharyngeal washings were taken frompersons who were in the first 48 hours of a commoncold infection. Half of each washing was put througha Berkefeld V candle and in each case the filtratecontained filter-passing anaerobes. The other halfwas filtered either through a Berkefeld W candle oran improved Seitz filter, when all attempts to demon-strate micro-organisms, either aerobic or anaerobic,in these filtrates failed. The experimental subjectswere inoculated intranasally and the pharynx swabbedwith small quantities of the same filtrate. In thefirst group of ten volunteers half received BerkefeldV filtrate and half Seitz filtrate. Two subjects in

1 Long, Perrin H., and Doull, James A.: Etiology of AcuteUpper Respiratory Infection (Common Cold).

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.eaeh group developed colds. From one of the latterserial passages were made through Seitz filtrates totwo other volunteers. In another experiment threesuccessful transmissions were made in series throughSeitz filtrates and a fourth passage was made througha Berkefeld W filtrate. These observations confirmand extend previous work, tending to prove thatthe infection of the common cold is due to a filter-

passing virus incapable of growing on any knownculture material.

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THE CAUSES OF HOOKWORM ANÆMIA.

AN adequate answer to the question of what causeshookworm anaemia has been brought nearer throughindependent investigations by A. J. Huart of Leiden,land by F. Fulleborn and W. Kikuth of Hamburg.2Huart infected dogs with very many larvae of Ancy-lostoma caninum and A. brazilienze. Blood appearedin the faeces on the ninth day, sometimes amountingto a bloody diarrhoea ; while after death the intestinalcontents varied from a blood-stained mucus to largeamounts of clotted blood with the underlying mucosasown with bites. Whether blood was found in thehookworms themselves depended on the intervalbetween the death of the host and the examination.If the latter was delayed the worms were free fromblood; if it was made immediately after death thegreat majority of them contained it. Now G. H.

Whipple showed over 20 years ago that a blood-filledhookworm placed in water could be watchedrapidly expelling blood, so that whether in Huart’sdogs the intestinal blood had mainly been swallowedand promptly wasted by the worms, or had mainlycome from their abandoned and oozing bites, is ’,immaterial for the present purpose. In these grave !ihookworm anemias, produced by as many as 3000worms in young dogs of 3 kg., there was severe I,bleeding into the intestinal lumen. How severe such Ibleeding may be is shown in the case of one of theHamburg dogs which died of an acute hookwormanaemia due to A. caninum. Its bowels had not been

opened for three days. The iron found in its intestinalcontents corresponded to 455 g. of the impoverishedblood then in its vessels, or to one-eleventh of its body-weight. This presumably represents the drain

produced by 1100 worms in three days. There is,then, no question that in these acute hookwormanaemias bleeding occurs into the intestine in great Iquantity. To conclude that it does not occur inchronic cases is unwarranted. It is noteworthy that

- viewed as food for the worms the whole of thisintestinal haemoglobin was sheer waste. Clayton Lanehas, however, found iron in the intestinal wall andbody wall of the hookworms of man, so that, in addi-tion to wasting hoemoglobin, they use it. Indeed,the food required by rapidly growing worms and byadult females laying 6000 to 10,000 eggs daily mustbe considerable, and it may confidently be concludedthat haemoglobin forms part of it. Blood is used aswell as extravagantly wasted by the worms.The Hamburg work, moreover, showed abundance

of pigment in spleen and bone-marrow, the liver beingunmentioned in this respect ; and although in thisinstance no iron could be found in the liver, the pig-ment found in spleen and marrow must have beenderived from haemoglobin just as malaria pigment isso derived. In malaria, another great cause of anaemia,there is destruction of red corpuscles in the circulation.Do hookworms produce a toxin which destroys redcorpuscles in the circulation ? That hookworms do

1 Acta Leidensia, 1929, iv., 48.2 Archiv f. Schiffs- u. Trop.-Hyg., 1929, xxiii., 171.

in fact produce toxins is shown partly by the eosino-philia which normally accompanies their presence,and partly by the intense degeneration with castingof the epithelium found by Hoeppli of Hamburg inthe convoluted tubes of the kidney of dogs in acutehookworm infection. As to what particular toxinsthe worm produces, evidence steadily accumulatesthat anticoagulins are present in its anterior part-namely, that part containing the large glands whichopen in or close to the mouth. This strongly supports.the view that blood is the essential food of hookworms,that they function as miniature leeches. But for the

presence in them of a haemolytic substance evidenceis conflicting, and after their fresh experimentsFulleborn and Kikuth leave the matter open. But,as Huart notes, haemolytic substances can be demon-strated in alcoholic and ethereal extracts of all normalorgans. Furthermore, the Hamburg investigators fedmice with dozens of hookworms each, or injected themwith their fresh or dried extracts to an extent whichrepresented as many as 300 worms apiece, withoutproducing the least anaemia. Acute hookworm anaemiais, then, essentially due to the grave intestinal haemor-rhage which accompanies it, yet in view of the damageproduced in the kidney, it is rash to brush aside toxicaction as a contributory cause.As regards the more usual chronic anaemia, it is

equally unreasonable to brush aside bleeding as a

negligible factor in its causation. On the other hand,the toxic changes in the kidneys in acute canine cases.are strongly reminiscent of those noted for man byB. K. Ashford and his colleagues in their report onthe Porto Rico Anaernia Commission for 1905-06.Fresh evidence for the effects of this toxic renal damageseems to be offered by-the observation of A. W. andJ. N. Taves, quoted by A. A. Osman,3 on the value ofalkaline therapy in reducing the time needed to,remove the gross lymph effusions of grave hookworm.disease, so allowing this condition to be viewed

alongside ordinary chronic parenchymatous nephritis.There is, then, abundant evidence of toxic damagein both acute and chronic hookworm infection, andits consequences should attract investigation ; but-there is no evidence that it is the important factor-in causing hookworm anaemia, and in some circum-stances there is clear evidence that it is not.

GEOGRAPHICAL INCIDENCE OF DIABETES.

Dr. C. A. Mills of Cincinnati has made a survey4 ofthe incidence of diabetes mellitus in various countries..He finds it uncommon among the Chinese, in whom itis mild and accompanied by supersensitiveness toinsulin. It is mild also, he says, in Japan and in Indiaexcept among the wealthy leisured classes. It has beenobserved that the incidence is greater among Chinesewho forsake their native diet for European foods, andamong Irish inhabitants of Boston, emigrants from acountry where the incidence is low. Dr. Mills thinksthe incidence is largely affected by climatic conditions,and has collected figures which show that in the U.S.A.the diabetic death-rate is lowest in the southern States,while the western plateau and mountain States comenext, followed by the northern States from Michiganwest, the middle States from the Atlantic to thePacific co.asts, and finally the north-eastern States,with a rate 2-2 times as high as that of the southerngroup. That this cannot be explained on racial

grounds has been shown by Lehman, who found thatdiabetes was as prevalent among negroes in the south

3 THE LANCET, Nov. 1st, p. 945.4 Arch. Internal Med., Oct., 1930, p. 569.