bluuebunny/crossref_metadata_2025_split 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 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.
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.