bluuebunny/crossref_metadata_2025 huggingface dataset:
On the variation of the specific phase of Salmonella amersfoort (n.sp.)
Authors: Henning M. W.
Published: May 2009

A new type of pathogenic Salmonella for the fowl has been described. Its somatic “O” antigen corresponds with factors VI, VII of potsdam. It occurs only in the specific phase, but its flagellar “H” antigen contains at least two distinct and separate antigenic complexes, which commonly occur in organisms that are not even remotely related. The one complex (the first, en-, antigen, α phase of Kauffmann and Mitsui) contains factors enx, which represent also the factors of the specific phase of abortus-equi. The other complex (the second, d-, antigen, β phase of Kauffmann and Mitsui) contains factor d, which comprises the type phase of stanley, muenchen and typhi.

Single cells containing factors enx on multiplying constantly yield variants containing factor d as well as offspring that retain antigenic complex enx. In the same way single cells containing apparently only specific factor d will bring forth new cells, most of which retain the parental antigenic structure, but a small proportion of the progeny will acquire specific factors enx instead of d.

When a broth culture of amersfoort in either the enx or d phase in an apparently pure form, as judged by the agglutination test, using heterologous sera which contain agglutinins either against factors enx (or en) or d, is used for the preparation of sera, agglutinins of approximately the same titre for both variants are produced in the sera.

As a result of the information given above the following antigenic structure is proposed for Salmonella amersfoort:

Somatic “O” antigen—VI, VII.

Flagellar “H” antigen—

(1) α phase of Kauffmann and Mitsui—enx.

(2) β phase of Kauffmann and Mitsui—d.
Vitamin C and Anaemia: With a Description of a Photo-Electric Colorimeter
Authors: Thomson Scott , Glazebrook A. J. , Millar W. G.
Published: May 2009

A new form of photo-electric photometer or colorimeter is described which permits of accurate and objective readings in a wide range of colorimetric work with small quantities of solutions. The instrument is of the null-point type and hence requires calibration to suit the particular estimation.

The writer is indebted to the Earl of Moray Fund of the University of Edinburgh for financial assistance towards the expenses of the earlier part of the work.

The original model was made by A. H. Baird of Edinburgh, the model described above by Wm. Watson and Sons, London, to whom, and to Mr W. E. Watson-Baker, I am indebted for suggestions on a number of points.
Studies on air-borne virus infections: I. Experimental technique and preliminary observations on influenza and infectious ectromelia
Authors: Edward D. G. ff. , Elford W. J. , Laidlaw P. P.
Published: May 2009

1. A method is described for the experimental investigation of aerosol systems formed by the atomization of suspensions of viruses into the atmosphere. Observations on the physical properties of such systems have been made, and an experimental approach found to certain practical problems connected with air-borne virus infections, particularly counter measures involving the use of ultra-violet light and aerosols of chemical antiseptics.

2. Mice, placed in an atmosphere into which the respective virus had been atomized, have contracted the diseases of influenza and infectious ectromelia in a manner closely analogous to naturally occurring air-borne infection.

3. The infection resulting from the inhalation of virus is described. The suggestion is made that this method of infection may be used with advantage (a)in studying in detail the histology of lung lesions, and (b) in obtaining more uniform infection of large batches of mice.

4. The two methods of experimental infection, (i) intranasal instillation under anaesthesia, and (ii) normal inhalation, have been compared and contrasted. It is deduced from the evidence available that as little as 1 % only of the virus may reach the lungs of mice breathing normally in an atmosphere containing dispersed nuclei of influenza virus.

We gratefully acknowledge the assistance we have received from Miss Dora Lush.
An outbreak of infantile gastro-enteritis in Aberdeen: The association of a special type ofBact. coliwith the infection
Authors: Giles C. , Sangster G.
Published: May 2009

1. Ninety-three cases of primary infective gastroenteritis are reviewed. In only one instance was a known pathogen isolated.

2. The clinical features, epidemiology and postmortem findings are discussed.

3. A serologically homogeneous strain ofBact. coliis described which was isolated in over 90% of cases.

4. A discussion follows on the significance of these findings.
The production of H2S-negative strains of Salmonella
Authors: Wilson W. James
Published: May 2009

It has been shown that certain strains of Salmonella grown in nutrient broth containing sulphite and bismuth, develop variants that are incapable of reducing sulphite to sulphides in the media of Wilson & Blair.

The altered strains showed no alterations in their antigenic and biochemical characters.
The feeding and breeding of laboratory animals: VII. Methods of testing the adequacy of diets for breeding mice
Authors: Bruce H. M. , Emmens C. W.
Published: May 2009

1. The application of factorial design to. the testing of diets for breeding mice is described.

2. The use of a system of monogamous making, by which the females have a continuous series of pregnancies with concurrent gestation and lactation, is advocated for such tests.

3. Present indications are that a high wheat content or a high yeast content is desirable in the diet of breeding mice.

4. A diet containing a considerable proportion of full-cream milk was very effective for breeding mice, but it is not yet certain that this constituent is necessary.
Population dynamics of sewer rats
Authors: Barnett S. A. , Bathard A. H.
Published: May 2009

1. The effects of poison treatments on the rat populations of two sample districts of heavily infested sewers in a London borough were studied.

2. Each district had a maximum rat population represented by a census figure of about 10,000 g. wheat eaten per day, corresponding to at least 400 rats.

3. Poison treatments after prebaiting, at intervals of 6 months, reduced the rat population of each district to less than 10% of the maximum. A rapid restoration of the population followed, and the level reached in 6 months was near the maximum.

4. In both areas, direct poisoning with sodium monofluoroacetate ‘1080’ was as effective as a prebaiting treatment. Direct poisoning with zinc phosphide was relatively unsuccessful.

5. When both areas received double treatments, consisting of direct poisoning with sodium monofluoroacetate followed by a prebaiting treatment, the estimated population of one district was reduced to about 3% of the maximum. In the other area, rain made the second poisoning ineffective.

6. The rate at which the population was restored from the 3% level was even higher than the rates previously observed, and was probably too high to be accounted for solely by breeding. Evidently, invasion from the surface played a part.

7. No relationship could be established between the estimated sewer rat population densities within each district, and the known sites of surface infestation.

We are grateful to the Council and officers of the Borough in which the work was done, for unstinted help throughout the inquiry. We also owe thanks to H. V. Thompson for help in the early stages; to him and to Miss M. D. A. Lawrence for discussing the work during its progress; to Miss M. M. Spencer for help in the analysis of the records and in checking calculations; and to A. G. Jenson for mapping the districts and for drawing the figures.
The action of staphylococcal toxins on isolated rabbit intestine
Authors: Anderson K. , James Dinah M. , Marks J.
Published: May 2009

Staphylococcal α- and β-toxins inhibited the spontaneous activity of isolated rabbit intestine, the former leading to an increase in tone and the latter to a decrease. The γ-toxin and δ-haemolysin had no effect in concentrations likely to be met in extracts of cultures, nor did δ-lysin enhance the action of β-toxin. Culture extracts in which the haemolytic toxins had been neutralized by antiserum sometimes produced an increase in tone or amplitude or both, which was moderate in degree but rapid in onset. This stimulation was more common with strains isolated from food-poisoning outbreaks than from infective lesions. It was occasionally observed with coagulase-negative strains and was therefore considered to be unrelated to enterotoxin. No effect on intestine was observed which could be considered specific for food-poisoning strains.

We are indebted to Dr R. E. O. Williams of the Central Public Health Laboratory, Colindale, for providing food-poisoning strains of staphylococci, to Dr H. W. Smith for strain CN, and the Wellcome Research Laboratories for gifts of sera.
The maintenance of stock strains of trichomonads by freezing
Authors: McEntegart M. G.
Published: May 2009

The ability of four species of trichomonads to withstand freezing was investigated with a view to storage of stock cultures. Of the conditions investigated the most satisfactory was found to be storage at – 79° C. following slow freezing, the protozoa being suspended in medium containing 10% glycerol.T. gallinaewas the most easily preserved and survived even without glycerol for 6 months. No observations on survival beyond this period have yet been made so the possible maximum time of survival is not known.

T. vaginalisremained viable for four months but deteriorated in storage and had died out after 6 months. The sample ofT. hominiscontaining 10 % glycerol was still viable after 6 months at – 79° C., but in the presence of 5 % glycerol survival was not observed beyond 4 months.T. foetuscould not be preserved under any of the conditions tested. The possible implications of these results are discussed.
Studies in the epidemiology of infectious myxomatosis of rabbits: VI. The Experimental Introduction of the European Strain of Myxoma Virus into Australian Wild Rabbit Populations
Authors: Fenner Frank , Poole W. E. , Marshall I. D. , Dyce A. L.
Published: May 2009

The primary lesions produced in rabbits by the intradermal inoculation of the virulent French strain of myxoma virus were clearly distinguishable from those produced by the standard laboratory strain or by attenuated Australian field strains. Based on this fact a screening test was developed which allowed classification of large numbers of samples of virus into French or attenuated Australian types.

The virulent French type of virus was introduced into the wild rabbit population at Lake Urana by the inoculation of 242 rabbits over a period of 6 weeks, the attenuated Australian strain of virus having been recovered from a naturally infected rabbit at the beginning of the series of inoculations. A severe outbreak of myxomatosis occurred in which an estimated 70% of cases were caused by the French strain of virus. In spite of the early predominance of cases due to this introduced strain the majority of samples obtained in the latter half of the outbreak were of the attenuated Australian type, and this was probably the only strain which survived through the following winter and caused an intense epizootic in the spring.

A similar picture of early establishment of the artificially introduced virulent French strain, and its subsequent replacement by the naturally occurring attenuated Australian strain, was seen at two other study sites, North Urana Station and Merricumbene.

We are greatly indebted to colleagues on the staff of the Wildlife Survey Section at Albury, especially Mr M. P. Hines, for assistance in the field work, and to Mr P. Bentley, the manager of Cocketgedong Station, on which the experimental site is situated. We have profited from numerous discussions with Mr F. N. Ratcliffe, and are grateful to Dr G. S. Watson for assistance in the statistical treatment of the results.
The behaviour of a mutant strain ofSalmonella typhimuriumin experimental mouse typhoid
Authors: Hobson Derek
Published: May 2009

A streptomycin-resistant mutant of a virulent strain ofSalm. typhimuriumwas less virulent to mice than the parent strain. The difference in virulence was only observed when mice were infected with small numbers of organisms. Although the mutant strain caused fewer deaths than the parent strain it remained capable of establishing persistent infection in the majority of animals.

The significant difference in the behaviour of the two strainsin vivowas that after clearance from the blood multiplication in the tissues began more rapidly with the virulent strain and was progressive, whereas multiplication of the mutant was delayed, was less in degree and was apparently suppressed within a few days of infection.

The mutant strain was apparently identical antigenically with the parent strain, and was equally toxic. The mice dying of infection with this strain did so when the bacterial population had reached a level similar to that in the terminal stage of infection with the virulent strain.

The essential difference between the two strains was the speed and probability of attaining a critical final population. The mutant strain ofSalm. typhimurium, bothin vitroandin vivo, had a slower growth rate than the parent strain. A possible hypothesis to explain the importance of this finding in relation to the outcome of infection has been discussed.

I am indebted to the Medical Research Council for the provision of a grant towards the expenses of this investigation and to Mr T. Norris and Miss Italia S. Alderton for technical assistance.
The complement activity of canine serum
Authors: Larin N. M. , Gaddum Rachel , Orbell W. G.
Published: May 2009

Quantitative studies have shown that the haemolytic activity of canine complement was in all essentials similar to guinea-pig complement. Canine serum which had been heated at 56° C. markedly enhanced the haemolytic activity of canine complement. The complement-enhancing power of heated canine serum was found to be increased with the concentration of serum up to 20%. Further concentration up to 50 % serum dilution, or the use of undiluted serum, resulted in a reduction of this effect.

Serum aliquots were either pro-complementary or anti-complementary tocn, depending on whether they were heated at 56 or 62° C.

Factors that possibly affect the complement-enhancement were investigated and evidence is presented which indicates that the electric charge on the protein particle is probably responsible for either the pro-complementary or anti-complementary serum activity; the mechanism of this, however, still remains obscure.

The present work shows also that canine complement can be used instead of guinea-pig complement for testing canine sera with virus antigen by the complement-fixation reaction, an advantage of this being that the use of canine complement permits the testing of canine sera which are anti-complementary to guinea-pig complement.

The data obtained are discussed in relation to canine complement and its specific activity.

The authors are indebted to Professor W. I. B. Beveridge for his constructive advice, to Dr R. R. A. Coombs for his helpful comments on the complement activity, and to Dr Christine E. Rice of the Animal Diseases Research Institute, Canada, who has generously supplied the zymosan.

Miss W. Barr and Miss M. Baker gave fine technical assistance throughout all the experiments. Miss M. Lambourne assisted in preparing the manuscript and graphs.
Poliovirus as an antigen
Authors: Stevens K. M.
Published: May 2009

Calculations have been carried out which indicate that poliovirus vaccine contains sufficient antigen to account for the observed antibody response.
The effect of vaccines and other substances upon the course of neurotropic virus infection
Authors: McLaren Anne
Published: May 2009

1. When GDVII virus was injected into the brains of mice, subsequent intracerebral injections of mixed pertussis and diphtheria prophylactic significantly shortened the incubation period. Subsequent intramuscular injections of mixed prophylactic had no influence on the course of the infection.

2. Intramuscular inoculation of either GDVII virus or EMC virus results in a marked localization of paralysis in the injected limb. With GDVII virus, the localization probably arises from the use of the sciatic nerve route for entry into the c.n.s., and is unaffected by injection of substances into the opposite limb. With EMC virus, localization can be modified by injections into the opposite limb.

3. When GDVII or EMC virus was injected by a peripheral route other than intramuscular, intramuscular injections of vaccines or normal mouse brain suspension induced localization of paralysis in the injected limb.

4. Intramuscular inoculation of vaccines increased mortality in mice injected into the same limb muscle with GDVII virus. Within the limits tested the later the vaccines were injected relative to the virus, the greater was the effect.

5. When the vaccines used were more than a few months old, this facilitating effect was replaced by a protective effect. Mice injected intramuscularly with aged vaccines were significantly more resistant than the controls to GDVII virus injected into the same muscle.

6. Intracerebral inoculation of vaccines, and to a lesser extent other substances, increased mortality in mice which had received intramuscular inoculations of GDVII virus, by allowing virus to pass directly from the blood into the brain. This resulted in a predominance of cerebral symptoms when the vaccines were injected immediately after the virus, but not when the interval was lengthened to 48 hr.

7. The mode of action of modifying factors in neurotropic virus infections is discussed in the light of these results.

This work was done in the Department of Zoology, Oxford University, during the tenure of a grant from the Medical Research Council. I also wish to thank the Nuffield Foundation for their support of the virus research carried on in the Department.

I am most grateful to Dr F. K. Sanders for his advice and criticism, as well as for provision of technical facilities, and to Dr Donald Michie for assistance with the statistical treatment of the data, and for much other help.
The quantitative assay of bacterial aerosols by electrostatic precipitation
Authors: Houwink E. H. , Rolvink W.
Published: May 2009

1. The electrostatic precipitation of single cell bacterial aerosols has been studied. Two types of electrostatic precipitators of the wire-in-tube construction have been developed. In one type the collector is a tube with nutrient agar, in the other a vertical water-film.

2. Collection efficiencies of 90 % and more could be obtained at sampling rates of 25 l./min. and tensions varying from 5 to 10 kV.

3. The survival of organisms in electrostatic precipitators has been measured in comparison with other samplers, viz. the slit sampler, membrane filters and impingers. The equivalence of the electrostatic precipitators and other samplers in sampling spore aerosols could be demonstrated. Aerosols containing vegetative organisms were sampled equally well in the agar tube precipitator as in the slit sampler. In the precipitator with water-film collector there is a loss ofc. 25 % of viable cells.

4. The practical advantage of the electrostatic precipitators is their very low air resistance.

The authors feel greatly indebted to Prof. Dr J. A. Cohen and Dr F. Wensinck for their helpful criticism of the manuscript, to Mr W. de Vries who designed and constructed the generator for extremely high tension; to Mr R. van Strik, Philips-Roxane (Weesp, Netherlands), for statistical advice and computations and to Miss H. Kranenburg for technical assistance.
The control of rats living between access points in sewers
Authors: Bentley E. W. , Bathard A. H. , Riley J. D.
Published: May 2009

1. The rat population of a main sewer was studied by means of census baits.

2. In a series of poison treatments extending over 4–5 months all rats visiting the access points were eliminated.

3. At the end of this period the population was 40–65% of what it was at the beginning.

This work would not have been possible without the generous assistance once more of Mr A. R. J. Vickery, Assistant District Engineer of the Chief Engineer's Department of the London County Council and members of his staff, and without the ready co-operation of the Borough Engineer, the Medical Officer of Health and the Chief Health Inspector of the Metropolitan Borough of Bethnal Green, through which area the sewer ran.
Observations on the bactericidal action of hexyl resorcinol aerosols
Authors: Darlow H.M. , Powell E.O. , Bale W.R. , Morris E.J.
Published: May 2009

The bactericidal action of hexyl resorcinol vapour on airborne clouds of a variety of micro-organisms including pathogens and a virus has been investigated. In addition to killing rates comparable with those found by previous investigators, a phenomenon, which we have called the initial kill, has been demonstrated and experiments carried out to explain its mechanism. Under certain circumstances it enhances the elimination of viable bacteria very substantially.

We are indebted for technical assistance to Corporal J. C. G. Harris, R.A.F., to Messrs B. F. Courtnay and C. M. R. Pitman, and to members of the Virus Research and Field Trials Sections.
Rinderpest Immunity in Calves: II. Active Immunization
Authors: Brown R. D.
Published: May 2009

Calves which were the progeny of rinderpest-susceptible dams were inoculated with lapinized rinderpest virus when 1 day to 2 months old. Their serological response, as measured by neutralizing antibody titre 21 days later, did not differ from that of adult susceptible cattle.

In calves born of rinderpest-immune cows, the serological response to caprinized rinderpest virus depended upon the level of maternally derived antibody. There were two critical levels, one below which all calves produced antibodies (serum titre of 0.7 or less) and another above which no antibody was formed (serum titre of 2.2 or more). Thus all animals aged 8 months or more at the time of inoculation were actively immunized but no calf aged 3 months or less reacted in this manner.

The response of calves with maternally derived antibody titres between 0.9 and 2.0 varied. There was a significant inverse relationship between the preinoculation titre and the amount of antibody formed during the following 3 weeks. A similar inverse relationship was shown between the pre-inoculation titre and the rate of production of antibody and its titre 1 year following inoculation.

Calves which possessed colostral antibody, and which were actively immunized by caprinized virus inoculation, did not necessarily show the usual clinical reaction. When such animals failed to become actively immunized there was no sensitization of the antibody-forming mechanism, a fact demonstrated by the lack of an anamnestic response to subsequent exposure to rinderpest virus antigen.

I owe thanks to many people: to Dr S. E. Piercy, Deputy Director, E.A.V.R.O., for advice and encouragement; to Mr G. R. Scott, Senior Virologist, E.A.V.R.O., for advice and encouragement and, with Mr G. J. Knight, for help in the statistical analysis of the data; to Dr M. H. French lately head of Division and Mr G. Lampkin, Joint Animal Industry Division of E.A.A.F.R.O. and E.A.V.R.O. for facilities for the inoculation of calves from rinderpest-immune dams with rinderpest vaccine; Mr J. M. Nightingale, Sasamua Estate, South Kinangop, and Mr J. Armstrong, Naivasha, for facilities for immunizing calves from rinderpest-susceptible dams; Mr C. S. Rampton, Mr N. Kerani and Mr F. Mwithiga for technical assistance.

This and the previous paper (see p. 427) are published by permission of the Director, East African Veterinary Research Organization.
Antirabic immunity in guinea-pigs induced by high egg passage Flury virus. The influence of the route of administration on the resistance to cerebral and extraneural challenge
Authors: Huygelen C.
Published: May 2009

Immunization experiments in guinea-pigs with high egg passage Flury virus gave the following results:

1. Intracerebral inoculation of the vaccine protects against subsequent intracerebral or peripheral challenge with fixed virus.

2. Intramuscular administration results in the development of a good immunity status to peripheral challenge.

3. Intramuscular or intravenous inoculation of the vaccine fails to protect against intracerebral challenge.
The detection of a carrier of multiple phage-types of Salmonella paratyphi B
Authors: Sloan R. S. , Wilson H. D. , Wright Helen A.
Published: May 2009

Polluted water from a stream caused three cases of infection with Salm. paratyphi B belonging to two phage-types. These phage-types and two others were isolated from the water.

One woman, aged 81, with a history of enteric fever 20 years previously was discovered to be a prolific carrier of at least three of these phage-types, and to be the source of the pollution.

We are greatly indebted to Mr G. K. Anderson, County Sanitary Inspector, Midlothian, and to his staff for the large volume of field work they carried out; to Dr E. S. Anderson and Dr A. Bernstein, Central Enteric Reference Laboratory and Bureau, Colindale, London for the phage-typing on which this survey is based; and to Mr James Sutherland, F.I.M.L.T., for his enthusiastic technical assistance.
Survival of bacteria in amoebic hepatic pus in vitro
Authors: Watson K. C.
Published: May 2009

1. Bacterial infection of amoebic hepatic abscess is a relatively uncommon event.

2. Investigations to demonstrate a possible bactericidal effect of liver pus in vitro indicated that small inocula, especially of young cultures, of Sh. sonnei, Staph. pyogenes and an organism of pseudomonas species were rendered sterile. Organisms such as Esch. coli, Saim. typhi, Saim. typhimurium, Sh. boydii and Strep.faecalis showed a drop in viable count during the first few hours of incubation followed by a logarithmic increase. The strain of A. aerogenes, on the other hand, was not decreased in numbers during the first few hours of incubation and showed a prolonged lag phase followed by a logarithmic increase in numbers. Shigella sonnei, Staph. pyogenes, Sh. boydii and Strep. fascalis attained to maximum population densities which were less than those obtained in control broth tubes and less than those of other organisms in liver pus.

3. It is suggested that secondary bacterial infection of amoebic liver abscess is often endogenous in origin, occurring after primary aspiration due to disinte gration of the lining wall of the cavity, allowing the entrance of portal blood containing organisms from the damaged bowel.
Sepsis in surgical wounds Multiple regression analysis applied to records of post-operative hospital sepsis
Authors: Lidwell O. M.
Published: May 2009

The method of multi-regression analysis as applied to data which are classified in a non-metric manner is discussed, and a set of data relating the risk of post-operation sepsis to various factors is analysed in this way.

Age over 60, male sex, long duration of operation, incision over 6 in. long and the insertion of a drain in the wound are all found to be associated with increased risk of post-operative sepsis. Operations for appendicectomy and those on the gall bladder have a relatively high basic risk of developing sepsis while operations for gastrectomy or those on the thyroid, and probably thoracic operations, have a low basic risk. The substantial differences in the gross risk of post-operative sepsis associated with the operations performed in the different hospitals included in the analysis are shown to be almost entirely accounted for by differences in the operations performed in them.
Newcastle disease as a model for studies of experimental epidemiology
Authors: Andrewes C. H. , Allison A. C.
Published: May 2009

Observations are reported on the mechanism of transmission of a neurotropic strain of Newcastle disease virus from infected to normal baby chicks. Infection appeared to be mediated mainly by large or very labile air-borne particles. Other factors examined were the time of maximum infectivity of chicks, the effects of duration of contact, of the social habits of the chicks and of the type of cage used to house them.

Results obtained by contact experiments were supported by tests in which settling virus particles were collected in Petri dishes placed at various distances from infected chicks.
The toxicity and acceptability of the sodium salt of pindone, an anti-coagulant rodenticide, to the house-mouse (Mus musculus L.)
Authors: Rowe F. P.
Published: May 2009

1. A 0·005% solution of the sodium salt of pindone was found to kill wild house-mice (Mus musculus) in 4–6 days. Mice offered a choice between this solution and water drank more water, but the difference in consumption was not statistically significant.

2. The addition of 1% sugar did not appreciably alter the palatability of a 0·005% solution, but a solution of the anti-coagulant containing 10% sugar was more readily accepted than water. This preference was maintained with solution 4 months old.
Immunity in mice to an intracerebral challenge ofBordetella pertussis
Authors: Holt L. B. , Spasojevic Vera , Dolby Jean M. , Standfast A. F. B.
Published: May 2009

The survival rate of mice actively or passively immunized against intracerebral challenge withBordetella pertussis, was independent of the size of challenge dose within the range of 20–2000 LD.

This unexpected result appears to be due to the anatomical peculiarities of the infected organ, in which circulating antibody does not pass the normal blood-brain barrier easily. The pertussis infection does not cause sufficient inflammation to induce a pathological increase in the permeability of the barrier until the number of living microbes in the brain reaches 10 to 10. Since this stage in the brain consistently occurs after 4–5 days, independently of the size of the inoculum within the range 20–2000 LD, the outcome of infection in the immunized animal depends solely on the degree of specific immunity.

In the non-immune mouse, the increase in permeability of the barrier persists until death. In the immunized mouse, the elimination of the infection leads to a restoration of the normal barrier at about the 6th day.
A village epidemic of brucellosis
Authors: Rozansky R. , Weber D. , Lehman E. , Bali S.
Published: May 2009

A village epidemic of brucellosis, due to Brucella melitensis, contracted from infected sheep and goats owned by the vifiagers is described. Of the 309 inhabitants eighty-four became infected and seventy-nine were clinically ill with brucellosis. The investigation covered 232 of the total population and nearly all those not examined belonged to the age group, 0–5 years, not directly exposed to infection by contact with diseased animals.

The population of the village was made up of forty-six families, only nine of which escaped infection. In the affected families, the incidence varied from one to seven in each case. The size of the family varied from three to eleven but there was no correlation between the size of the family and the number contracting brucellosis, neither did sex play any part in the incidence. All age groups were susceptible but the morbidity increased with age and this was correlated with increased risk of exposure to infection of the older age groups.

There was considerable variation in the severity of the clinical illness but there were no fatiities and all patients responded to antibiotic therapy.

Brucella melitensis was isolated from twenty-eight of the thirty-six patients subjected to blood culture and specific agglutinins at an acceptable level were demonstrated in all but three of those with a clinical illness.

The number of persons without evidence of clinical brucellosis who possessed significant brucella agglutinins was very small and the assumption that in an endemic area the number of infected persons is much greater than the number clinically ill was not borne out in the outbreak described here.

Persistence of specific agglutinins up to 2 years after recovery from the clinical illness is recorded.

We wish to pay tribute to the late Professor J. Gurevitch for his constant interest and helpful advice.

Thanks are due to Prof. M. Ruiz Castaneda for providing us with the Castaneda bottles for blood culture work, to Dr E. Neeman of the Government Brucella Reference Laboratory for supplying the Standard Brucella Antigen and for examining the strains of Brucella isolated, and to Colonel H. J. Bensted for his interest and help in preparing the paper. Finally, we are indebted to Mrs Aliza Abut Kayner, social worker in the village health centre, for her valuable help in gathering statistical data.
The quantitative assay of mono-dispersed aerosols of bacteria and bacteriophage by electrostatic precipitation
Authors: Morris E. J. , Darlow H. M. , Peel J. F. H. , Wright W. C.
Published: May 2009

Three tubular electrostatic precipitators are described for the assay of bacterial and bacteriophage aerosols. Particles can be sampled directly on agar or on agar-impregnated paper in a wide range of aerosol concentrations, or sampled into a fluid for the assay of airborne micro-organisms. Rapid consecutive sampling is possible with the samplers and a collection efficiency approaching 100% is readily obtained. Their sampling efficiency is compared with that of the slit sampler and the liquid impinger.
Observations on the possible role of filth flies in the epizootiology of bovine cysticercosis in Kenya
Authors: Round M. C.
Published: May 2009

The literature on the dissemination of helminth ova by flies is reviewed. In experiments using various species of filth flies, it was shown that ova of Taenia saginata Goeze 1782 can be passed out for periods of up to 11 days after ingestion, and viability of such ova was demonstrated for three days after ingestion. The possible methods of dissemination of ova are discussed together with the longevity of ova on pasture and the dispersal habits of flies. It is suggested that in Kenya, filth flies may play an important role in the epizootiology of bovine cysticercosis.
The survival ofShigella sonneion cotton, glass, wood, paper, and metal at various temperatures
Authors: Nakamura Mitsuru
Published: May 2009

1. Ten strains ofSh. sonneiwere placed upon metal, wood, cotton, paper, and glass and held at −20°, 4°, 15°, 37° and 45° C. Survival of the cells was most extensive when placed at −20° C. and practically none of the strains survived when held at 45° C.

2. Slight variations in the survival of different strains was observed when the cells were placed upon glass and cotton. Strain variation was greater when survival time was measured by placingSh. sonneion wood, paper, and metal.
Respiratory viruses in a residential nursery
Authors: Sutton R. N. P.
Published: May 2009

A longitudinal survey of respiratory illness in a Sheffield residential nursery is described. Over 8 months, outbreaks of respiratory illness occurred, two of which were associated with infection by Influenza A and Parainfluenza 3 viruses. The symptomatology is described of the illnesses resulting from these infections. The incidence of adenovirus recoveries over the same period was also investigated and suggests that adenoviruses of Types 1, 2 and 5 may be components of the normal viral flora of the nasopharynx in infants.
Linear relationships in complement fixation
Authors: Fulton F. , Almeida J. O.
Published: May 2009

Over a certain range there is a linear relationship between the amount of complement required for 50 % lysis and the amounts of one of the variables in the primary reaction mixture of a complement-fixation test when the third variable is present in a quantity sufficient to allow maximum fixation.

If this linear relationship were maintained as the concentration of the selected variable is progressively reduced, there would also be a linear relationship between the logarithms of the amounts of complement fixed and the logarithms of the amounts of the selected variable; in this case, the line with logarithmic co-ordinates will necessarily have unit slope.

When the fixation of small amounts of complement by several virus systems is measured, an approximately linear relationship using logarithmic co-ordinates has been demonstrated, but in many cases the line does not have unit slope. In this range, therefore, there is not a linear relationship when arithmetic co-ordinates are used.

A new design for a complement-fixation test is proposed, using isohaemolytic curves.
Staphylococcal sepsis in mothers and newborn babies
Authors: Spink M. S.
Published: May 2009

A serious outbreak of staphylococcal infections in the maternity units in Blackburn was investigated. There were considerably more than one hundred cases of breast abscesses altogether, well over half of which occurred in primiparae. Staphylococcus aureus, phage type 80, was the predominating organism throughout the outbreak and at the peak period during the early part of the outbreak this type was responsible for nearly 80% of the infections.

After the introduction of a number of procedures for the general reduction of cross-infection the incidence of breast abscess fell markedly and a controlled trial of an antibacterial cream, containing neomycin and hibitane, which was applied to the nasal mucosa of all infants and mothers in the test group of patients, was undertaken. The conditions obtaining in the test and control groups were identical in every way except that the control patients did not receive the neomycin-hibitane cream. There were about 1250 mothers and infants each in the test and control groups; the incidence of breast abscesses in the test group was 0·8% and in the control group it was 2·7%. The method adopted for the detection and treatment of carriers among the nursing staff broke down on two occasions; this fact and the emergence of an unforeseen source resulted in a larger number of infections than should have occurred. Had it not been for these incidents there is little doubt that the trial would have shown more conclusively the effectiveness of the neomycinhibitane cream, by the method laid down, in reducing cross-infection.

Investigation of the bacterial flora on the nasal mucosa of over 1000 infants in the control group yielded results of considerable interest. Of 300 cases where there was early colonization by Staph. albus, this organism established its dominating position in 70% of the cases and it was not subsequently displaced by Staph. aureus. The significance of this observation and the evidence favouring nasal dissemination of Staph.aureus as the most important cause of hospital cross-infection are discussed.
The measurement of the D-antigen in poliovirus preparations
Authors: Beale A. J. , Mason P. J.
Published: May 2009

A simple micro-method of measuring ‘D-’ and ‘C-’ antigen contents of poliovirus preparations is described. The D-antigen of poliovirus is almost certainly the component of the virus involved in eliciting neutralizing antibodies, and the D-antigen assay thus becomes a simplein vitromethod for assessing the antigenic potency of poliovaccines and for investigating the influence of various factors upon the antigen. The value of the technique in following the concentration and purification of poliovirus preparations is illustrated in the studies reported in the accompanying paper by Fantes (1962). The results of experiments designed to test the validity of the idea that D-antigen is the antigen eliciting neutralizing antibodies are discussed by Beale (1961).
Experimental intestinal coliform infections in mice
Authors: Ashburner Frances M. , Mushin Rose
Published: May 2009

A technique involving the suppression of normal intestinal flora with antibiotics, and the introduction of streptomycin-resistant coliforms was used for the study of infections in mice.

It was shown thatEscherichia coli, both the enteropathogenic and normal faecal strains, tend to colonize the upper intestinal tract as well as the lower region. An oral dose of ten or less cells could produce a chronic infection. Infections were asymptomatic even with an initial dose of 109bacteria. There was no indication of growth advantages for enteropathogenic coliforms in competition with normal.
A new enrichment medium for salmonellae
Authors: Banič S
Published: May 2009

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 ofSalmonella typhiand 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.
A survey of measles antibodies in different populations
Authors: Smith Gillian Tilden
Published: May 2009

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.
Influenza haemagglutination-inhibition antibodies in Sydney
Authors: Cossart Y. E.
Published: May 2009

Haemagglutination-inhibiting antibodies against A, A′ and A2strains of influenza virus and against one strain of influenza B were estimated in sera from blood donors in Sydney in February 1958 and in April and October 1961.

The A2antibody increased substantially while both A and A′ antibodies declined slightly. There was a great decline in influenza B antibody during the same period.

Thanks are due to Dr Phyllis M. Rountree who suggested this study. Miss Patricia Taylor gave excellent technical assistance in the early part of this work.
The toxicity of 0·025% warfarin to wild house-mice (Mus musculus L.)
Authors: Rowe F. P. , Redfern R.
Published: May 2009

1. Individually caged wild house-mice (Mus musculus L.) were fed 0·025% warfarin in a pinhead oatmeal/oil/sugar base. In all, 345 mice were tested for a fixed period ranging between 4 and 28 days.

2. There was considerable variation in the susceptibility of individual mice. The lowest effective dosage was 26·1 mg./kg. of body weight in 4 days and the highest dosage survived was 1067·2 mg./kg. eaten over 21 days.

3. The time required to obtain a 100% kill of house-mouse populations with 0·025% warfarin under field conditions is discussed.

We thank the Director of the United States Department of the Interior, Fish and Wildlife Service, for permission to quote from the Quarterly Report of that Service.
Streptococcal school outbreaks: a method of investigation and control
Authors: Boissard Joan M. , Fry R. M.
Published: May 2009

A method of controlling outbreaks of streptococcal infection of the upper respiratory tract in communities such as boarding schools is described.

It is suggested that, in a search for carriers, nose and mouth swabs should be taken in place of the customary nose and throat swabs. These swabs will detect those who are dispersing streptococci into the environment, as distinct from the carriers who are not dispersers. It is essential that infections of the skin and ears should also be looked for.

It is recommended that all dispersers, whether nose or mouth positive, should receive sulphanilamide insufflation in both nostrils twice daily for a week, or longer if necessary, without exclusion from school. In addition, penicillin lozenges for 2 days may be recommended for the mouth positives only.

The history is considered to be an important factor in deciding the extent of the initial investigation, and examples are given to illustrate this. When mass swabbing is considered necessary, it is highly desirable that the whole community should be swabbed at the same time, as early as possible in the outbreak. It is also desirable that bacteriological follow-up should be available to check that control has been effected.
Quantal and graded dose-responses of bluetongue virus: a comparison of their sensitivity as assay methods for neutralizing antibody
Authors: Svehag Sven-Eric
Published: May 2009

The sensitivity of quantal and graded responses to mouse-adapted bluetongue virus for the detection of neutralizing antibody was compared using probit and rankit analysis. The graded response, based on survival times, allowed the demonstration of antibody in highly dilute serum, in which antibody was not detected by the quantal response recording percentage death.

Quantal responses to bluetongue virus variants were compared with theoretical dose-response curves constructed according to the Poisson distribution for the random variation of virus particles in inocula. Of these theoretical curves the first term in the Poisson distribution gave the best approximation to the experimental data but the fit to normal distribution curves was better. The quantal responses to bluetongue virus did not appear to reflect the random variation of one-or-more infectious virus particles in inocula.

In graded responses to bluetongue virus, a rectilinear relationship was observed between reciprocal harmonic means of survival times and log virus dilutions.
A comparative trial of norbormide and zinc phosphide against Rattus norvegicus on farms
Authors: Rennison B. D. , Hammond L. E. , Jones G. L.
Published: May 2009

Norbormide at 1·0 and 0·5% and zinc phosphide at 5·0 and 2·5% were each tested in four types of cereal bait, after prebaiting and as direct poisons, against infestations of R. norvegicus on forty-eight farms in Montgomeryshire.

The relative success of treatments was measured by the reduction in the number of takes from wheat baits put down for 2 days, 13 or 16 days before, and 5 days after, poisoning.

Treatments with zinc phosphide were significantly more successful than those with norbormide, irrespective of the cereal bait, concentration of poison or method of treatment used, and in spite of conditions on many farms that partially restricted the distribution of the baits containing zinc phosphide.

Differences between these results and results of laboratory tests with the same rodenticides are discussed.

Norbormide is recommended for use in situations where zinc phosphide cannot be used efficiently without risk to livestock.

We are indebted to Messrs Tavolek Laboratories Limited, Slough, for the free supply of norbormide made available early in the trial; also to Messrs. Lloyd and Pritchard, who were responsible for all the treatments; to Miss E. J. Taylor and Miss P. Cullen for assistance with some of the census baiting, and to J. H. Greaves for permission to examine original data and present them in Table 3.