1. Modifications of the technique of colicine typing are reported which allow more rapid and economical identification of Shigella sonnei for epidemiological purposes without loss of accuracy.

2. The technique is epidemiologically valid as judged by the constancy of type in repeated isolations from individuals and the uniformity of type in epidemics; it is considered that the few instances of lack of uniformity in these indices are probably examples of true mixed type infection. There is no evidence of type instability in vitro.

3. Type incidence differs significantly from that reported in two other centres; a new colicine type (Type 14) is described which brings the total of recognizable types to 16. It is considered that in addition to the five types which were previously thought distinctive, three other Types, 6, 11 and 14, can now be so regarded.

4. There is a need for continued studies to resolve the few discrepancies associated with infection by more than one type either in the individual or in an epidemic; it is hoped that colicine typing will reawaken interest in Sonne dysentery.

This investigation was supported (in part) by Public Health Service Research Grant AI– 04833–01.from the National Institute of Allergy and Infectious Diseases.

The protection afforded by cholera vaccine administered by the intradermal route, and demonstrated by active and passive mouse protection tests, active guinea-pig protection tests, and agglutination titres, is excellent and equal to that given by subcutaneous inoculation.

It is suggested that cholera vaccine administered by the intradermal route would greatly reduce the incidence of reactions which occur when the vaccine is given subcutaneously.

A new enrichment medium for the isolation of salmonella types from faeces is described.

The inhibitory substances for coliform organisms and enterococci in this medium are magnesium chloride and sodium hydrogen selenite.

The new medium was found in routine diagnostic work to be superior to the Mueller–Kauffmann medium in the isolation of Salmonella typhi and only a little inferior in the isolation of other salmonella types.

When used in addition to the standard media the new medium increases the number of positive results.

I am indebted to Dr Jadranka Zajc-Satler for the identification of the salmonella types isolated and to Mrs I. Mamilovič, Miss P. Ferbežar, and Mrs D. Zavodnik for technical assistance.

The efficiencies of bactericides in destroying bacteria on woollen blanket were investigated on a laboratory scale. The bactericides were not effective when tested with new blanket; this low efficiency was found to be related to the rapid adsorption of the bactericides by the wool. Pretreatment of the wool with concentrated solutions of bactericides depressed the rate of depletion of the bactericides from subsequent washing liquors with bactericides at customary concentrations, and led to more satisfactory rates of kill (inactivation factors about 106).

The test organisms, Staphylococcus aureus and Escherichia coli, were applied to the blanket as a powder, and the relative densities of bacteria on the blanket were determined using a procedure based on maceration of the fabric. The bactericides, 4-chloro-3, 5-xylenol (P.C.M.X.), cetyl trimethyl ammonium bromide (C.T.A.B.) and bis-(4-chlorophenyl diguanido)-hexane diacetate (chlorhexidine diacetate) were tested in the presence of appropriate detergents.

Cultures were kindly supplied by Dr Hildred Butler of the Royal Women's Hospital, Melbourne.

Eight carriers of intestinal pathogens (5 Salm. typhi-murium, 2 Sh. sonnei, 1 E. coli 026) were given their own coliforms, rendered drug-resistant in vitro to neomycin or paromomycin, together with one of these drugs. In seven cases, the drug-resistant coliform flora established itself, while the natural coliform flora and the pathogen were suppressed. In four cases only (2 Sh. sonnei, 2 Salm. typhi-murium) the pathogen was eliminated in the course of this procedure.

A survey of serum samples from all age groups in the population has shown a rapid acquisition of antibody between the ages of 1 and 6 years which reaches a plateau in concentration and does not disappear later.

The concentration of antibody in cord serum may be four or more times greater than that in the mother's serum.

Presence or absence of a record of past infection by measles is not necessarily reflected by the titre of antibody in the serum.

Low antibody titres in very young infants may be due to an imperfectly developed antibody producing mechanism.

The author gratefully acknowledges the assistance of all those who made this survey possible. In particular, she is indebted to Dr G. I. Watson of the College of General Practitioners and his colleagues (see list) for their help in the collection of so many of the serum samples, and to Mr D. A. Bamgboye for his excellent technical assistance.

1. Following an epizootic of louping ill on certain farms in south-west Ayrshire in 1960, a long-term study of several farms was initiated.

2. The flocks on two hirsels of one farm were studied during spring and early summer of 1961. Although only one lamb death was confirmed as due to louping ill, the infection rates in sentinel hoggs on the two hirsels were 50–60. and 11% respectively. The difference between the hirsels is probably attributable to the difference in the amount of tick habitat on them.

3. The ewes were bled in March and June and their lambs in June. Haemagglutinin inhibition (HI) and neutralization tests revealed that the HI antibody is much shorter lasting than neutralizing antibody. Many ewes, therefore, had neutralizing but not HI antibody. Otherwise agreement between the tests was good. In March almost all the ewes aged 3 years or more had antibody. Of the gimmers (2-year-olds) about two-thirds on one hirsel and one-third on the other had antibody in March: by June almost all the former and about half of the latter had antibody.

4. About two-thirds of the lambs had the same antibody status as their mothers in June and almost all the rest had less antibody than their mothers. Serological evidence suggestive of louping ill without recognizable clinical disease was found in six lambs and a further lamb recovered from clinical disease.

5. Revaccination of two-thirds of the flock failed to cause any detectable change in antibody status.

6. The epidemiology and pathogenesis are discussed in relation to immunity and infection rates, and to the design of control measures.

We are greatly indebted to the late Mr James Murdoch at Dalmellington, Mr John Murdoch at Dalcairnie Farm, and Mr David Murdoch at Knockgray Farm for permission to work on their farms and for all the help they gave us during the study.

Variation in agglutinating and protective antigens was studied in a strain of Trypanosoma brucei growing in mice protected with anti-trypanosomal rabbit serum. It was concluded that the agglutinating and protective antigens were the same, and that variation in the antigenic structure of trypanosome populations exposed to antiserum was due to mutation and selection rather than to adaptation. The mutation rate per organism per division cycle required to account for the experimental findings on the mutational hypothesis was found to have a mean value of 10−5.17.

A total of twenty-five grade cattle were infected experimentally with a strain of rinderpest virus of moderately high virulence (RGK/1). Three methods of introduction of the virus were employed, i.e. subcutaneous or intranasal inoculation (14 animals) and housing in contact with reacting cattle (11 animals).

A quantitative study of the viraemia and of virus excretion by the nasal, urinary and faecal routes, was made by the inoculation of primary calf kidney cultures. All virological data were related to the onset of pyrexia, the incubation period in inoculated animals being 3–5 days, while in those infected by contact it was 8–11 days. Viraemia preceded the first rise of temperature by as much as 2 days in inoculated animals and 1 day in the contact cases. All animals had viraemia by the 4th day of the disease, but thereafter the percentage of positives declined rapidly, reaching nil by the 9th day.

The case mortality rate was 48 % with the majority of animals dying on the 7th to 10th days after reaction.

Virus was detected in the nasal secretions of some animals on the 2nd day preceding pyrexia. The proportion of nasal excretors rose slowly to reach a maximum of 87·5 % on the 4th day and no positives were detected after the 9th day of fever. The titre of virus in nasal discharges reached high levels, often probably in the region of 105·0 to 106·0 TCD 50/ml.

Urinary excretion of virus began on the 1st day of fever in about 25 % of animals; reaching a maximum of 62·5 % on the 7th day. No virus was recovered from the urine after the 8th day of the disease, the rapid decline in the excretor rate being only partially attributable to the death of severe cases. Urinary titres were relatively low; they seldom exceeded 102·0 TCD 50/ml.

Virus was first recovered from the faeces on the 3rd day of pyrexia. Excretion by this route was not constantly associated with the development of diarrhoea, but the rapid decline which occurred in the excretor rate on the 8th and 9th days was undoubtedly attributable to the death of diarrhoeic individuals which took place at that time. The majority of faecal titres were in the approximate range of 103·0 to 104·0 TCD 50/g. but occasional samples attained ca. 106·0 TCD 50/g.

It was calculated, from the clinical and virological data that cattle can excrete virus, at least by the nasal route, as much as 6 days before the appearance of pathognomonic clinical signs, i.e. oral necrosis and erosion.

Our findings for rinderpest were compared with those of other investigators of this disease and also with the available information on canine distemper and human measles.

We are very grateful for their able technical assistance to Messrs L. W. Rowe, C. S. Rampton and R. F. Staple. Particular thanks are due to Mr C. S. Rampton for his preparation of all the figures. We have received considerable and indispensable help from our junior laboratory staff, especially Mr Francis Ngugi Gachuhi and Mr Joash Adero.

This paper is published by permission of Mr H. R. Binns, C.M.G., O.B.E., the Director of the East African Veterinary Research Organization.

A simple, laboratory scale, stirred system has been developed to examine conditions of culture necessary for optimum return of infective virus from explants of surviving bovine tongue epithelium, with particular bias towards large-scale procedures.

Control of hydrogen-ion concentration and aeration of the culture are emphasized.

The authors wish to thank Dr I. A. Galloway and Dr J. B. Brooksby for their helpful advice in preparing this paper, Mrs J. Lansley for her untiring technical assistance and Mr J. Goodridge who constructed the culture apparatus.

Experiments reported here were performed on the sera of thirty-three volunteers who were infected or inoculated intranasally or intramuscularly in groups of five to nine with one of two enteroviruses, namely, echovirus 11 and coxsackievirus A21 or with one of three rhinoviruses, namely, M viruses P.K. and ECHO 28, and H virus D.C. Antibody responses occurred against the virus administered, and rarely against the other viruses used. It was concluded that although these viruses are related biologically the antibody responses in the volunteers were largely specific.

Applying a method of selective separation of the specific high polymers the intracellular site of the specific substance in the Copenhagen strain of Pneumococcus Type II was demonstrated, by electron microscopy; the specific polymeric material assumed to form the capsule is situated within the bacterial cell and the electron density of this material is sufficiently high to permit its detection.

The possibility of obtaining electron micrographs of the polymeric substances as contained in the cells or after their diffusion into the medium or when secreted as slime, suggests that the current concept of the capsules as the site of the specific substances may have to be reviewed.

The electron micrographs were made by Dr A. Petrovici to whom I express my thanks.