449

diminish scouring in calves given insufficient colostrumor whey to ensure their normal growth.The hormone control of milk secretion naturally

received considerable attention at the institute. Itseems clear that l-thyroxine is as effective as iodinatedcasein as a stimulant of milk secretion. In the decliningstage of lactation its administration gave increased

yields up to an extra half-gallon of milk per cow per day,with increases in heart-rates up to 20 beats per minute.The main effect on composition of the milk was to increasethe fat and lactose and diminish the protein, but thechanges were not great. Experiments have shown thatpure anterior-pituitary growth hormone has galacto-poietic properties in lactating cows. The previousreport from the institute that A.C.T.H. had similar

properties has not been confirmed.The bacteriology of milk, cheese, and butter has also

been thoroughly studied. Progress reports of herds keptfree from Streptococcus agalactiœ illustrate both thedifficulties and the possibilities of reducing bovinemastitis in this way. The antibiotic nisin appearsto be of considerable value in the treatment of thisinfection.Naturally the institute has many collaborators, a

satisfactory number of whom are also engaged in medicalresearch. Indeed, this report might well be quoted asevidence that the distinction between medical and

agricultural research is administrative rather thanoperational.

TOUGH TUMOUR CELLS

AN encouraging feature of experimental cancer

research is that the control experiments sometimesprove unexpectedly instructive. There is an exampleof this in the annual report of the Yorkshire Councilof the British Empire Cancer Campaign for 1949-50.Prof. R. D. Passey and Dr. L. Dmochowski, of Leeds,describe the control experiments they undertook to

repair what in their view was an omission in the workreported by Gye and his colleagues 1 last year, when theyshowed that mouse sarcomas and carcinomas could stilltransmit the same type of tumour after being frozento-79°C and desiccated to powder and subsequentlythawed and reconstituted. Passey and Dmochowskiconfirmed these findings but could not accept the con-clusion that, without controls, they necessarily indicatedthe presence of a virus. Gye et al. held that, judged byappearances, the dryish cells were no longer viable,despite the seemingly intact nuclei in their string-likecytoplasm. At the January meeting of the Patho-

logical Society of Great Britain and Ireland, the Leedscritics recounted how they had dried similar mousesarcoma tissue under the same conditions and resuspendedthe cells in diluent, and had now found nothing in theappearances of the cells to suggest that they were notviable. In support of their interpretation-that thecells were the source of transmission of the tumours-Passey and Dmochowski spun the resuspended cellsfor 3 minutes at 2600-7000 g, which would precipitatecells but not any of the known animal viruses. Thusthey brought about a physical separation between diluent,which might contain virus, and cells which might beviable. Deposit and supernatant fluid were next

separated and injected into mice. Tumours grew fromthe cell-containing fraction only. In the discussion atthis meeting, R. J. Ludford suggested that any remain-ing doubt about the viability of the cells might beremoved by observing their behaviour in tissue culture.This test, promised in the present report, was sub-sequently performed with the assistance of I. Glucksmannof the Strangeways Laboratory, Cambridge. At thejoint meeting of the pathological societies of this country1. Gye, W. E. Brit. med. J. 1949, i, 511. Mann, I. Ibid, ii, 251, 253.

Gye, W. E., Begg, A. M., Craigie, J., Mann, I. Brit. J. Cancer,1949, 3, 259.

and Holland, held in Amsterdam in April, photomicro-graphs of outgrowing and dividing cells were shownwhich convinced those who saw them that some of the

harshly treated cells had indeed survived and reproducedthemselves even in the unfavourable conditions of tissueculture. The original experiments contained their ownwarning of probable disproof, for dried mammary tumoursgrew at the point of inoculation in connective tissuesof male as well as female mice iri a time interval consonantwith cell-grafting rather than with the action of a virus.Four other research centres 2 have since reported dis-

agreement with the interpretation of Gye et- al., and ithas been shown that when the drying period is slightlyprolonged the transmission of tumours fails.

Rabbits are proving suitable for testing chemicalsthat induce bladder cancer. From Sheffield Prof. H. N.Green reports the induction of one ureteric tumour ina rabbit within about 2 years of feeding with acetylamino-fluorene. Dr. G. Bonser, in Leeds, has induced onebladder tumour and one ureteric papilloma, besidesother changes suggestive of malignancy, within 5 yearswith the same chemical. She has promising experimentson hand with betanaphthylamine. If rabbits respondto both carcinogens by developing tumours of the urinarytract, this animal will have advantages over the dog inease of handling and cheapness, though none in pointof time. Mice respond only to the first compound andmany develop hepatomas as well. The rabbit tumoursare limited to the urinary tract.

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Statistical inquiries into the inheritance of mammarycancer in this country have yielded no evidence that theincidence was any greater among 584 mothers of

patients with this disease than among the same numberof unselected women in the general population. Thisresult, checked by the evidence of breast tumours inliving daughters and by the death certificates of themothers, conflicts with observations reported from theContinent which suggest that there is some familialassociation. Examination of human milk by electronmicroscopy for evidence of an infective milk agentanalogous with Bittner’s agent in mice is proceedingbut has not yet reached a reportable stage.

GENERAL PRACTICE IN NORTHERN IRELAND

THE Northern Ireland committee of the NuffieldProvincial Hospitals Trust has decided to make an

independent survey of the conditions of general practicein the region. The main objects are to improve thestatus of the general practitioner and to find, if possible,how he can obtain reasonable time for leisure, contactwith his colleagues, and postgraduate study. Theassumption is that any improvement which can be madeon these lines will be reflected in improved service to thepatient. Dr. J. A. Fisher, formerly of the NuffieldDepartment of Clinical Medicine, Oxford, has been

appointed to make the survey, which will be based onsample surveys, questionaries, and direct interviewswith the practitioners. Although the Nuffield surveyis independent, it is being made with the approval andencouragement of the North Ireland Ministry of Health,the Health Services Board, and other interestedauthorities in the region.

THE INDEX and title-page to Vol. I, 1950, which wascompleted with THE LANCET of June 24, is now inpreparation. A copy will be sent gratis to subscriberson receipt of a postcard addressed to the Manager ofTHE LANCET, 7, Adam Street, Adelphi, W.C.2. Sub-scribers who have not already indicated their desire toreceive indexes regularly as published should do so

now.

2. British Empire Cancer Campaign, Annual Report for 1949-50.