RK 13 and primary PMK and VMK cell cultures were compared for the isolation of RV by means of the simultaneous inoculation of original specimens and early passage material. RK 13 was found to be the most sensitive and reliable and provided a result for both isolation and neutralization in the shortest time. As the interpretation of CPE and the propagation of these cultures is sometimes difficult, the simultaneous use of a second system in which RV is easy to identify, e.g. VMK or PMK cell cultures, is recommended. Both PMK cell cultures and LLC-RK1 were suitable for isolating RV from clinical specimens. Preliminary studies with LLC-RK 1 indicate that it may provide an even more sensitive alternative to RK 13, but further studies employing clinical material require to be carried out before firm conclusions can be reached.

For maximum utilization of deep cultures to produce FMD virus it was important to have adequate control of culture temperature and pH. Culture temperature should be controlled within the range 34·25°7–35°C. and culture pH at 7·2. The culture system became less efficient as the cell concentration was increased from 1 × 106·0 to 9 × 106·0 cells/ml. A cell concentration of 2·5 × 106·0 cells/ml. represented a working compromise between efficiency and antigen titre/ml. for inactivated FMD vaccine production.

The input virus/cell ratio had no effect on the time or titre of peak virus yield in the range 1:1 to 1:320. This makes the production of seed virus from small numbers of monolayer cultures feasible and economical.

Virus yield was improved by the addition of 5% serum. It would be more satisfactory if a serum-free cell strain could be developed.

Between 1964 and 1966 comparative studies were carried out in Aberdeen, Scotland, and in village settlements in Fiji on the clinico-epidemiological features of molluscum contagiosum. In Aberdeen there was a positive correlation between this disease and attendance of patients at public swimming baths. The preponderance of male patients in Aberdeen was attributed to their more frequent indulgence in swimming. Household spread of the condition was rare in Aberdeen but common in Fiji. Lesions frequently occurred unilaterally or were situated on opposing skin surfaces. They were mainly central in distribution in Aberdeen, the axilla being a site of predilection. In Fijians, peripheral lesions were fairly common though palms and soles were not affected. Peak age incidence in Aberdeen was 10–12 years, contrasting with a peak at 2–3 years in Fiji. Opportunity for contagious exposure appeared to be the main factor determining transmission of molluscum contagiosum between hosts, this opportunity occurring frequently and early in life in Fiji but only under special circumstances and later in childhood in Aberdeen. However, the age distributions in the two populations suggested the possible operation of immunological as well as environmental factors in determining the overall pattern of disease in the community.

We should like to express our thanks to the following people whose support and co-operation made this joint study possible: Dr K. J. Gilchrist, Principal of the Fiji School of Medicine; Prof J. A. R. Miles, Department of Microbiology, University of Otago; Dr C. H. Gurd, Director of Medical Services, Fiji; and Prof. A. Macdonald, Department of Bacteriology, University of Aberdeen. We are indebted to Dr T. E. Anderson and Dr R. A. Main of the Aberdeen Royal Infirmary for referring patients, to Mr W. Hodgkiss of the Torry Research Station, Aberdeen for carrying out the electron microscopy and to Dr Peter Bennett, Nuffield Foundation Scholar in Tropical Medicine from Aberdeen in 1962, who brought to the attention of the Aberdeen workers the prevalence of molluscum contagiosum in Fiji. Part of the work was supported by a grant to R. Postlethwaite from the British Empire Cancer Campaign for Research. Mr (now Dr) Ian Simpson and Miss Helen Adam were supported by Nuffield Foundation Scholarships in Tropical Medicine, and Dr J. A. Watt by a Garden Research Fellowship from the University of Aberdeen.

Four strains of Edwardsiella tarda, a recently described member of the Entero-bacteriaceae, were studied, They were isolated from four out of 832 children during a 3-year survey of juvenile diarrhoea at Vellore, S. India. Three of the four children had diarrhoea when the organisms were isolated and one was convalescent from bacillary dysentery. From this study and a review of the literature it appears that Ed. tarda is found only infrequently in man and that its main reservoir may be in animals such as snakes and seals. It is suggested that this organism should be specifically looked for in cases of diarrhoea to determine its etiological role, particularly when the major intestinal pathogens are not isolated.

This work forms part of the studies on the etiology of diarrhoeal infections in children for the Ph.D thesis of P.B., and the grant from the Indian Council for Medical Research towards these studies is gratefully acknowledged. We also wish to thank Dr Sakazaki for serotyping the strains.

Minimum inhibitory concentrations of tetracycline to 256 tetracycline-resistant strains of Staphylococcus aureus were determined. M.I.C.'s tetracycline were appreciably higher among mercury resistant than among mercury sensitive strains.

Mercury resistant strains representing various M.I.C.'s tetracycline grew significantly better in peptone water containing a therapeutic concentration of tetracycline than mercury sensitive strains representing the same range of resistance. The experiment was repeated after both groups had been adapted—or ‘trained’—to grow on agar containing tetracycline, 100µg./ml. The mercury sensitive strains now grew better than the mercury resistant group.

The significance of these findings is discussed. It is concluded that tetracycline resistance is more stable and efficient in mercury resistant strains, and that it is probably genetic in origin—the result of mutation and selection. Tetracycline resistance in mercury sensitive strains is possibly the result of ‘training’.

The associations and significance of both mercury resistance and tetracycline resistance in Staphylococcus aureus are discussed.

Preliminary typing of 1820 strains of Staph. aureus from 51 herds with the human set of phages showed that non-typable strains were common (31·4%). Other phages were investigated and 1404 strains from 328 herds were typed with 42 phages; these included the human phage set, phages from Weybridge and phages isolated in Brisbane. The following 20 phages were selected as suitable for typing bovine strains of Staph. aureus in Australia: 29, 80, 13, 71, 6, 7, 42E, 47, 53, 77, 31B, 42D, 81, 101, 102, 107, 110, 600, 367, 425. Phages 13, 367, 425, 600 were from Brisbane and 101, 102, 107 and 110 were from Weybridge.

Salmonellas were isolated from 278 of 800 (34·7 %) samples of frozen carcass or boneless horsemeat from South America and from 101 of 751 (13·5%) samples of frozen boneless beef. However, the percentage of contamination detected depends to a large degree on the method of examination. Contamination was mostly external, a fact which points to slaughterhouse contamination. Boneless meat was contaminated to a higher degree than carcass meat.

Sera were obtained from about half of the Tristan da Cunha islanders on reaching Cape Town in October 1961, a few months after reaching Britain and before returning to the Island in 1963.

After vaccination against current influenza A 2 and B serotypes antibodies were evoked against earlier serotypes, in particular against influenza A1 of 1951 with which the islanders had almost certainly been infected. Those who failed to develop antibody against A 2 and B after vaccination developed it later presumably owing to natural infection.

Almost all islanders developed antibodies against parainfluenza 3 and 1 and some against parainfluenza 2 and coxsackie A 21 viruses. There were no antibody rises against reoviruses.

The incidence of rinderpest infection in game animals in selected localities of South Kenya and North Tanganyika was studied during the period 1960 to 1963. Serum samples from 590 wildebeest (Connochaetes taurinus), 48 eland (Taurotragus oryx), 65 Thompson's gazelle (Gazella thompsoni) and 39 Grant's gazelle (Gazella granti) were tested for rinderpest neutralizing antibody.

Rinderpest infection was shown to have been very frequent in yearling wilde-beest in the Mara area of Kenya in 1959/60, in the Serengeti National Park of Tanganyika in late 1960 and also in the Serengeti, and some adjacent areas, during the latter half of 1961. In the Ngorongoro Crater in 1961 infection was far less widespread, with only 11% of the yearlings acquiring antibody, compared to 67% in the Serengeti. The infections in 1959 and 1960 were clinical epizootics, accompanied by a considerable mortality, whereas no overt disease was reported in the course of 1961. Eland were affected in a similar manner to wildebeest up to 1960 but only a low rate of serological conversion was demonstrated in 1961. Adult Thompson's gazelle showed a low rate (ca. 12%) of infection but no anti-body was detected in Grant's gazelle.

Only a small proportion of the wildebeest calves born in early 1962 acquired antibody by mid-1963 and this was due, at least in part, to infection late in 1962; it was not clear, unfortunately, whether the positive animals belonged entirely to resident, as opposed to migratory, groups. No clinical signs or mortality were reported in this year.

A low incidence of rinderpest infection in wildebeest was also demonstrated both before and after 1960 in the Kajiado district of Kenya, where disease of game has not been reported in recent years. It is possible that the positive animals, as also the 1962 cases in Tanganyika, acquired the virus from low-grade infections of cattle.

The transmission of rinderpest antibody from wildebeest dam to calf, presumably via the colostrum, was demonstrated regularly, except in six calves about 1–2 weeks old. No completely satisfactory explanation was obtained for their failure to acquire passive antibody but it may have been due to abnormal disturbance in the herds, associated with the shooting. The antibody titres in calves were initially higher than those in the serum of their dams but by the end of the 3rd month this position had been reversed. Individual calves became serologically negative from about the 10th week of life and all were devoid of antibody by the 6th to 7th month. The half-life of passively-acquired antibody was 4·4 weeks.

Eight strains of Cl. welchii were studied for the heat-resistance of their spores. Spores of Cl. welchii isolated from food-poisoning cases had greater heat-resistance than strains isolated from soil or faeces. D-values and trend values were calculated from the thermal death curves.

The dip-slide, consisting of a glass microscope slide coated with nutrient medium and inoculated by dipping in freshly voided urine, provides a simple measure of the bacterial concentration in fresh urine. This is a useful supplement to the usual microscopy and culture of urine in the diagnosis of urinary tract infections in general practice, when specimens cannot be delivered to a laboratory within several hours of collection, particularly when urine specimens have to travel by post. Dip-slides are also useful as the sole test in screening for symptomless bacteriuria.

1. A simple method for the long-term viable-preservation of samples of Leptospira suspensions is described. Quantities of about 25 μl., with the addition of 77·5 % glycerol, are introduced into capillary tubes, cooled slowly to −79° C. and stored at that temperature.

2. More than half the attempts were successful in re-establishing growth in culture after storage at −79° C. for periods up to 27 months.

3. The possibility that the method could be used for establishing ‘banks’ of standard Leptospira material for reference is discussed.

Staphylococcal colonization and infection were studied prospectively in infants, mothers and households after childbirth at home and in hospital. Infants were treated prophylactically with frequent applications of ‘Ster-zac’ hexachlorophane dusting powder. Some were treated in addition with ‘Naseptin’ nasal disinfectant cream.

The incidence of staphylococcal sepsis in infants was much less than before the adoption of hexachlorophane prophylaxis. The sepsis rate was further reduced when ‘Naseptin’ was used in addition to hexachlorophane. Of the two prophylactic agents, hexachlorophane was the more convenient and probably the more effective. ‘Naseptin’ was difficult to employ correctly and unsuitable for routine use.

The treatment of infants with disinfectants reduced nasal carriage markedly in infants and to a smaller extent in mothers. Both agents contributed to the reductions which persisted for some weeks after treatment ceased.

Breast abscesses were almost entirely confined to mothers of infants who became nasal carriers by the second week of life.

Staphylococcal colonization of infant's skin was greater when they wore impervious garments, probably because skin moisture increased.

Sera from 1029 individuals, 864 from Edinburgh and 165 from Oxford, have been examined for the presence of antibodies to Herpesvirus hominis. The results of the smaller Oxford survey did not reveal a higher incidence of antibody where direct comparison was possible with those from Edinburgh.

The incidence of both complement-fixing and neutralizing antibodies in the sera from 710 people in Edinburgh with ages varying from 1 month to 92 years was compared with the more complete of the earlier surveys, and in particular with that of Holzel et al. (1953) in Manchester, England. This comparison revealed a lower incidence of antibody in people under 25 in Edinburgh in 1965.

Results obtained with sera from medical students in Oxford and Edinburgh and from nurses in Edinburgh were in agreement with those of previous surveys. The low incidence of antibody in these young people emphasized the possible occupational risk of infection from patients and that primary herpetic infection might be encountered more frequently than before in teenagers and young adults.

Neutralization and complement-fixation tests to detect rubella antibody are described. Results of such tests show that between 80 and 95% of adults in England and Wales have neutralizing antibody. The presence of complement-fixing antibody indicates recent infection with rubella virus.

Results are presented showing the development of neutralizing and complement-fixing antibody after rubella.

Antibody tests on children with congenital rubella and their mothers are detailed. It is noted that higher neutralizing antibody titres are found in this group than in the general population.

Attention is drawn to the confused epidemiological picture experienced in investigating outbreaks of salmonellosis due to multiple serotypes. Public Health Laboratories are often faced with the examination of specimens containing several serotypes and in this paper six techniques are described which have been found useful in dealing with this problem. The choice of technique depends on the time available for the examination and the epidemiological importance of obtaining an accurate result. A preference is expressed for an immuno-isolation technique, in which the bacteriologist is in technical control of the isolation of specific serotypes. The method is possibly open to objection on the grounds of serological induction of new serotypes, but we should regard this danger as slight in the majority of samples examined.