bluuebunny/crossref_metadata_2025 huggingface dataset:
The immunogenicity of heat-inactivated vaccinia virus in rabbits
Authors: Madeley C. R.
Published: May 2009

Rabbits were immunized by multiple intradermal injections followed by six intravenous doses of vaccinia virus inactivated by heating to 65° C. Particular attention was paid to confirming that the virus used was fully inactivated and incapable of reactivation. The immunized rabbits developed neutralizing and other antibodies to a titre comparable with those developed in response to live virus, but multiple intravenous injections were required to elicit a maximum titre. A qualitatively different response was seen only in immunodiffusion tests in agar gel where two or three fewer lines developed with antisera to heated virus than with those to live virus. The rabbits were subsequently challenged intradermally either with vaccinia and cowpox or with rabbitpox. They showed some immunity to vaccinia and cowpox, compared with normal controls, but less than that elicited by live virus. Their resistance to lethal doses of rabbitpox was life-saving though some rabbits did develop lesions. Later rechallenge of the rabbits showed that they had not developed further immunity, in distinction from the normal controls. The implications of these findings are discussed.

I wish to thank the National Fund for Research into Poliomyelitis and Other Crippling Diseases for their generous support in providing a Research Fellowship during which this work was done. I wish to thank also Professor A. W. Downie F.R.S. and the Staff of the Department of Bacteriology, University of Liverpool, for their encouragement and assistance respectively.
Studies on the inhibitory properties of sodium thioglycollate on the germination of wet spores of clostridia
Authors: Mossel D. A. A. , Beerens H.
Published: May 2009

Wet spores of fourteen strains ofClostridium, representing eight species, were enumerated in four different types of thioglycollate agar and in a similar medium in which thioglycollate was replaced by cysteine-HCl. Thioglycollate appeared to be toxic, in principle, to almost all strains tested, although the degree of toxicity was influenced by other components of the medium. These experiments entirely confirm earlier observations and must lead to the conclusion that the use of thioglycollate in sterility test media should be discontinued and that cysteine-HCl should be used as the redox potential reducing compound instead.
Sources of salmonellas in market swine
Authors: Williams L. P. , Newell K. W.
Published: May 2009

A commercial swine fattening ration containing animal origin ingredients was shown to be related to the salmonella excretion of market pigs being sent to slaughter from a well-managed farm. When similar animals from this farm were fed a ration of much lower salmonella content, due to exclusion of ingredients of animal origin, their excretion declined as measured by both rectal and caecal swabs. When subsequent lots of pigs consumed a pelleted weaner ration and the special supplement only, before being exposed to a supplement containing the usual level of contamination, they seemed to be refractory to infection. Probably, this was a function of age at first exposure.

With prospective methods it was possible to show that salmonellas from the abattoir environment could infect pigs, that they would excrete them within a very short time, and that organisms from this source could be demonstrated at slaughter and shown to be a cause of carcass contamination.

While these findings support the view that the build-up of salmonellas hi pigs is by contact with a contaminated environment, they indicate that the primary source of the contamination is most probably the salmonella-excreting pig which has consumed contaminated feed ingredients on its farm of origin.

If the great majority of pigs went to slaughter salmonella-free they would not serve as a source of infection to other pigs being sent to slaughter. Their intestinal contents could not contaminate carcass sides in the slaughtering process. This should help to prevent the contamination with salmonellas of the food preparation area of both homes and commercial eating establishments.
A modification of the growth-inhibition test and its use for detectingMycoplasma mycoidesvar.mycoides
Authors: Davies G. , Read W. C. S.
Published: May 2009

A modification of the growth-inhibition test for identifyingMycoplasmaspecies is described. The modification simplifies the screening of a large number of strains for one species. Experiments showed that it was effective and specific when used to identifyM. mycoidesvar.mycoides. Its use in studying the epidemiology of contagious bovine pleuropneumonia is discussed.

This work was financed in part by the United States of America Agency for International Development under the terms of the CCTA/AID Joint Project 16 for research on contagious bovine pleuropneumonia.

We wish to thank Dr R. H. Leach for the various bovine mycoplasma cultures.
The hygiene of slicing machines, carving knives and can-openers
Authors: Gilbert R. J. , Maurer Isobel M.
Published: May 2009

Experiments have been made in several supermarkets, shops and cafés to determine the bacterial counts on slicing machines, carving knives and can-openers after contact with various cooked and canned meats, and to find a simple, quick and effective cleaning method for such articles of equipment. The importance of personal effort in cleaning rather than a reliance on the known attributes of detergent/disinfectants is stressed. The methods available for testing the efficiency of cleaning procedures are outlined.

In vitro tests have shown that the detergent/disinfectant used in the present study at a concentration of 0·75 % (w/v) was satisfactory. This concentration was the minimum inhibitory concentration for Salmonella paratyphi B, which was the most resistant of fifteen strains of bacteria studied.

The design of slicing machines and can-openers is discussed in relation to safety in use and ease of cleaning. Recommendations concerning the necessity of regular and effective cleaning of food-handling equipment and storage of cooked and canned meats before and after slicing are given.
Live influenza B vaccine in volunteers
Authors: Beare A. S. , Tyrrell D. A. J. , Hobson D. , Howells C. H. L. , Pereira M. S. , Pollock T. M. , Tyler L. E.
Published: May 2009

A trial of an experimental live influenza B vaccine has been described.

The virus it contained was active and produced infections, antibody rises and clinical reactions.

Second and third vaccinations had much less effect than the first. Resistance to revaccination was only partially reflected in the serological response.

It seems that another factor, probably local antibody, exerts a considerable influence on resistance to infection with influenza viruses.

We are greatly indebted to Dr P. G. Higgins of the Public Health Laboratory, Cirencester, who went to much trouble to provide us with specimens from patients with influenza; to Dr H. G. Pereira of the National Institute for Medical Research for the antigenic analysis of the vaccine virus; to Messrs Sankey Ltd., Bilston, Wolverhampton, for their unfailing courtesy and forbearance throughout the trial; to the volunteers for their enthusiastic co-operation in the face of some discom forts; and to Messrs Pfizer Ltd., Sandwich, for originally providing facilities for the preparation of the vaccine.

In particular we wish to record our gratitude for the invaluable technical help of Miss Pamela Ball of the Common Cold Research Unit, Mrs Maria Gregory of the Bacteriology Department of Liverpool University, Mrs L. Johnson of the Virus Laboratory of New Cross Hospital, Wolverhampton, and Mr A. Westoby, an assistant in the practice of Dr Tyler.
Factors affecting lecithinase activity and production inClostridium welchii
Authors: Nakamura M. , Schulze Judith A. , Cross W. R.
Published: May 2009

A variety of factors that affect lecithinase activity and lecithinase production byCl. welchiiwere studied. The lecithinase activity was time and temperature dependent. The optimum temperature varied from 30° to 46° C. according to the strain ofCl. welchiiemployed. Maximum lecithinase activity was produced after 12–60 hr. There was considerable strain variation. This could easily account for the differences in the published data.

Commercial purified lecithinase was more readily destroyed by heat than the lecithinase produced byCl. welchiiin culture media. The enzyme inactivation pattern at 60° C. was similar to that at 90° C. This is not in agreement with the reports of others who found that less enzyme was inactivated at the higher temperatures.

Acid pH values completely inactivated the enzyme. However, alkaline pH values did not significantly destroy the enzyme. The lecithovitellin reaction was completely inhibited at pH values of 1–5. The optimum pH for the reaction was around pH 7–8.

The production of lecithinase was dependent upon the pH of the culture medium. One strain produced measurable lecithinase at pH values of 5·5–8·5, whereas another strain produced lecithinase only at pH values 6–5–7–5.

Lecithin stimulated the production of lecithinase in a chemically defined medium.
An appraisal of sewage pollution along a section of the Natal coast
Authors: Livingstone D. J.
Published: May 2009

A bacteriological survey was made on the distribution and occurrence of coliforms and pathogenic indicators of pollution within the surf-zone and near-shore waters along a section of the Natal Coast, prior to the use of submarine outfalls. The distance covered measured approximately 47 miles. The waters sampled and assessed ranged from ‘clean’ beaches to heavily polluted areas; a single short run off an Eastern Cape coastal region was included for comparative purposes. In all cases, the bacteriological picture was related to sanitary features on the shore. The method is based on Escherichia coli I counts, parasite units, staphylococci, salmonellas and salinity, and provides an objective approach to the assessment of any future changes in water quality consequent on development.
Air-movement control for treatment and isolation rooms
Authors: Baird G. , Whyte W.
Published: May 2009

The degree of protection provided by various air movement control systems, as applied to isolation and treatment rooms, has been assessed. The main factors influencing the efficiency of isolation were the air supply rate to the room and the time the door was left open. The effect of some other possible factors, such as temperature differences and method of air distribution, are discussed.

The type of facilities provided must depend on the type of patient and economics, but prediction equations, which allow the assessment of positive, negative and balanced ventilation systems, are presented. The ventilation requirements for isolation rooms should be assessed individually, but for a treatment room a balanced system of ventilation with between 500 and 1000 ft.3/min. should be very effective. Precautions should be taken to ensure the air quantities are balanced and temperature differences are minimized. An air lock should not be necessary for balanced systems provided these rooms are in a mechanically ventilated ward.

We thank Mr W. Carson and members of the Building Services Research Unit for their help and advice and Sister M. F. D. Muir and the staff of the experimental ward for their co-operation. This work was sponsored by the Nuffield Provincial Hospitals Trust.

Requests for reprints, or a fuller description of the ward unit and test results, should be addressed to George Baird, Building Services Research Unit, 3 Lilybank Gardens, Glasgow, W. 2.
Dose-response relationships of lymphocytic choriomeningitis viruses in mice and L cell tube cultures
Authors: Lehmann-Grube F.
Published: May 2009

The dose—response relationships between two strains of lymphocytic choriomeningitis virus (WE3and Armstrong) and two hosts (mice and L cell tube cultures) were determined. The statistical analysis showed that, if infection was regarded as the response, and in the case of Armstrong virus in mice also death, the shapes of the empirical dose—response curves did not deviate from expectation which was based on the zero term of the Poisson distribution. Hence, the hypothesis that individual infectious units are capable of initiating infection and that co-operation is not required, was not contradicted. Furthermore, the units of assay were found to be equally susceptible under the experimental conditions applied.

By way of contrast, the relationship between WE3virus and mice dying after intracerebral inoculations was found to be more complex. In this case the empirical curve did not run the expected sigmoid course at all, but rather was bell-shaped with a maximum of mortality (92%) at approximately 50 ID 50.

The work was supported by a research grant from the Deutsche Forschungs-gemeinschaft.
A minerals-modified glutamate medium for the enumeration of coliform organisms in water
Authors:   Public Health Laboratory Service
Published: May 2009

Oxoid dehydrated MacConkey broth was compared with laboratory-prepared Gray's improved formate lactose glutamate medium and with two dehydrated versions of it, by participants in ten laboratories. A variety of chlorinated and unchlorinated water samples was used. The superiority of the glutamate media over MacConkey broth for the detection of coliform organisms in water was again confirmed. The minerals-modified version, either dehydrated or laboratory-prepared, gave the best results and is the medium recommended for use in water examination. Care should be taken to ensure that the final pH after sterilization is 6·7.
The antigens ofMycoplasma hominis
Authors: Hollingdale M. R. , Lemcke Ruth M.
Published: May 2009

A genital strain ofMycoplasma hominiswas fractionated by differential centrifugation after disruption of the cells by alternate cycles of freezing and thawing, by gas cavitation under nitrogen, or by ultrasonic treatment.

Antigens of the cell membrane were distinct from those in the soluble cell contents, judging from metabolic inhibition (MI), indirect haemagglutination (IHA), gel-diffusion and immunoelectrophoresis tests, and by the antibody response in rabbits inoculated with these fractions. The antigens which gave rise to MI and IHA antibody were located in the cell membrane.

Extraction of whole cells ofM. hominisby various chemical methods suggested that the active components were protein in nature and that there was no lipid hapten, as inM. pneumoniae, or polysaccharide, as inM. mycoidesvar.mycoides.

This work was partly supported by a Medical Research Council grant, which provided the remuneration of MRH.

We thank Professor R. A. Kekwick and Dr J. M. Creeth of the Biophysics Department of this Institute for their advice on the processing of plasma and density gradient centrifugation, and Mr F. C. Belton of the Microbiological Research Establishment, Porton, Wilts, for growing a 50 litre batch ofM. hominis.
Trachoma vaccine field trials in The Gambia
Authors: Sowa Shiona , Sowa J. , Collier L. H. , Blyth W. A.
Published: May 2009

The ability of two live trachoma vaccines to protect against naturally acquired infection was tested in young Gambian children. With a mineral oil adjuvant vaccine prepared from a Gambian strain of trachoma (MRC–187) a barely significant measure of protection was demonstrable 6 months after the first dose, but not at 1 year, despite a reinforcing dose given 6 months after the first. In a later trial an aqueous vaccine prepared from the ‘fast-killing’ variants of strains ‘SA–2’ and ‘ASGH’ failed to induce immunity. Two years after vaccination, the proportion of vaccinated children progressing to cicatricial trachoma was less than in the controls, and the average severity of the disease in terms of clinical score was greater; vaccine-induced hypersensitivity may have contributed to this result.

Irrespective of whether they had received trachoma vaccine, children with completely normal eyes at the outset were less likely to acquire trachoma than those with slight conjunctival folliculosis or papillary hyperplasia. In children acquiring trachoma, there was a highly significant positive correlation between severity of the disease and the presence of conjunctival inclusions. The pattern of trachoma differed significantly in the two villages used in both trials; the prev alence, severity and proportion of inclusion-positive subjects were all higher in the village with the greater population density.

An efficient follow-up organization, use of a slit-lamp for clinical observations, and a scoring system for recording physical signs are all desirable for trachoma vaccine field trials.

We are highly indebted to Dr G. Turner (Lister Institute, Elstree, Herts) for his assistance in making the vaccine used for Trial II; to Dr N. M. Lam (Pfizer Ltd.) and Dr C. H. Smith (Evans Medical Ltd.) for making the Trial III vaccine; to Dr I. A. Sutherland (M.R.C. Statistical Unit) for his advice and help with the statistical aspects; to the Pennsylvania Refinery Co. Inc. for a generous gift of Drakeol 6 VR; and to Mr M. Race for his invaluable technical assistance in The Gambia. We are also grateful to the Director and staff of the M.R.C. Laboratories, The Gambia, for various facilities; and to The Gambian Government for per mission to undertake these trials.
Selection for resistance to myxomatosis in domestic rabbits (Oryctolagus cuniculus)
Authors: Sobey W. R.
Published: May 2009

1. Response to selection was achieved with all strains of Myxoma virus used.

2. Heritability of resistance to myxomatosis was determined by intra-sire correlation using survival time as an index and by an all-or-none probit analysis. Both resulted in an estimate of heritability of about 35–40%.

3. The ability of animals to survive myxomatosis varied widely with environ mental variation in time.

I am indebted to W. Menzies for his very able assistance in all aspects of the work; to Dorothy Conolly for her critical assistance with data analysis, and to Dr J. M. Rendel for suggesting the probit analysis for determining heritability.
The incidence of complement-fixing antibody to varicella-zoster virus in hospital patients and blood donors
Authors: Tomlinson A. H. , MacCallum F. O.
Published: May 2009

The sera of 308 patients, not suffering from varicella or zoster infections, and the sera of 183 blood donors were examined for complement-fixing antibody to varicella-zoster virus. In both groups about 70% of sera from persons aged 11–40 years had antibody titres ≥ 1/4; the incidence was less in the age range 41–60 years and increased in later decades. Antibody titres of 1/16 or 1/32 were noticeably less frequent in those aged 41–60 years than in younger or older groups.

It was concluded that an unchanging titre of 1/16 or 1/32 was of no diagnostic significance. The age distribution of antibody was consistent with the theory that zoster only occurs when antibody has declined.
The excretion of two virulent strains of African swine fever virus by domestic pigs
Authors: Greig A. , Plowright W.
Published: May 2009

Daily observations were made on the excretion of African swine fever (ASF) virus by pigs infected intranasally or by contact. Two strains of virus having mean death times of approximately 3 and 6 days were used, the latter being recently isolated from a warthog.

First excretion usually occurred by the nasopharyngeal route, as early as 1 or 2 days before the onset of fever in many cases. The titres of pharyngeal and nasal swabs rose rapidly to reach mean levels of about 104–106 HAD 50 at 48–72 hr. following the onset of pyrexia. Virus in the secretions of the conjunctiva or lower urogenital tract appeared later and did not attain such high levels. Faecal and urinary excretion was of relatively little significance, except in slower infections caused by the recent warthog virus.

These results are discussed in relation to the known failure of infected pigs to transmit the disease to stallmates during the first 12–24 hr. of pyrexia and also in relation to recent work on the pathogenesis of ASF in domestic swine.
Lesions experimentally produced by fungi implicated in extrinsic allergic alveolitis
Authors: Bulman R. A. , Stretton R. J.
Published: May 2009

The ability ofAureobasidium pullulans, Cladosporium herbarumandCryptostroma corticaleto produce local lesions in the rabbit was examined. BothC. corticaleandA. pullulanscan survivein vivoand produce the inflammatory response typical of mycetoma.C. herbarumfailed to grow or survivein vivo.
Food preferences of wild house-mice (Mus musculus L.)
Authors: Rowe F. P. , Bradfield A. , Redfern R.
Published: May 2009

The relative acceptance of various plain foods by wild house-mice (Mus musculus L.) was compared in laboratory choice tests. The palatability of glycerine and six oils, each included at 5% in pinhead oatmeal, was compared in a similar manner.

The most favoured food was found to be whole canary seed (Phalaris canariensis). Pinhead oatmeal and wheat were also comparatively well accepted. Glycerine, corn oil, arachis oil and mineral oil were more palatable than either olive, linseed or cod-liver oils.

The results of the choice tests are considered in relation to the use of poison baits for the control of free-living mice.
On the Haemolytic Immune Isolysins of the Ox and their Relation to the Question of Individuality and Blood-relationship
Authors: Todd Charles , White R. G.
Published: May 2009

The term “Isolysin” was first employed by Ehrlich and Morgenroth in the third of their now classical series of papers entitled “Studies on Haemolysis(1).” It had been shown by Bordet that if the red blood corpuscles of an animal A are injected into another animal B, of a different species, the serum of B develops a haemolysin for the corpuscles of A. This haemolysin being produced in a different species of animal from that yielding the corpuscles, is termed, according to Ehrlich's nomenclature, a heterolysin.
The Spermicidal Powers of Chemical Contraceptives. VI. An Improved Test for Suppositories
Authors: Baker John R. , Ranson R. M.
Published: May 2009

1. A fluid is described in which cavy sperms react to the most diverse substances almost exactly as do human sperms in human semen. This fluid, called albumen-saline, consists of:

0·9% sodium chloride solution … 0·7 c.c.
Egg-white … … … … 2·3 c.c.

2. A detailed description is given of a new technique for comparing the spermicidal powers and rate of disintegration of suppositories (including foam tablets).

3. The new test differs from the old chiefly in allowing only five minutes for the spermicide to act, and in requiring the actual killing of the sperms and not only their immobilisation.

4. Of the commercial suppositories tested, Rendell and Finil are the most spermicidal, followed by Vimule, Speton, Semori, Prorace (chinosol) and Martindale, in that order. None of them is sufficiently spermicidal to encourage complete reliance in the absence of other contraceptive methods.
Stock Diet for Rats
Authors: Thomson W.
Published: May 2009

From time to time workers in various laboratories have published details of diets capable of maintaining their respective rat colonies in good health and supplying reasonably uniform animals for laboratory requirements. In response to enquiries regarding our feeding methods, the present note records the stock diet used at this Institute.
The Application of the Principle of Eijkman's Fermentation Test for Determining theColiTitre of Water
Authors: Minkevich J. E. , Alexandrov N. J. , Soboleva E. J.
Published: May 2009

At present thecolititre of water is almost universally determined by fermentation tests in sugar-containing media; the fermentation method of Eijkman (glucose-peptone solution at 46°2) and that of Bulir (neutral-red mannite bouillon at 46°) are current in many European countries, while in America fermentation in lactose bouillon at 37° is the standard test. Fermentation tests at 37° in lactose-containing media with the addition of bile and bactericidal dyes are also widely used (Great Britain, America).
A Contribution to the Problem of the Virulence (“VI”) Antigen of B. typhosus
Authors: Dyachenko S. S.
Published: May 2009

1. The strains of B. typhosus, which are inagglutinable, or non-sensitive to somatic O agglutinins, are virulent, whereas the agglutinable, or sensitive strains, show a low virulence.

2. Virulence and inagglutinability of strains seem to depend upon the presence in them of a virulence (Vi) antigen.

3. A considerable protective action, observed by means of active and passive immunisation, is exerted by the inagglutinable strain used (205 D), because it contains Vi antigen.

4. When the O and H agglutinins are eliminated through absorption, the agglutination reaction may serve to demonstrate in vitro the presence of the Vi antibody.
The Biochemical Reactions of Vibrios
Authors: Heiberg Børge
Published: May 2009

In reply to Gardner and Venkatraman's rejection of the use of biochemical reactions in the grouping of vibrios according to Heiberg's method, it is shown that in forty-five of the strains examined by Gardner and Venkatraman it is possible to exclude twenty-four as being classical cholera vibrios by means of fermentation reactions with certain sugars, i.e. mannose, saccharose and arabinose. The author believes that it is not possible to deny the value of such reactions in attempting to group vibrios. The constancy of the reactions is emphasised.
Nasal Diphtheria Carriers
Authors: Rudolf G. De M. , Ashby W. R.
Published: May 2009

1. A series of 62 nasal carriers of B. diphtheriae, virulent and avirulent, has been investigated.

2. Treatment by means of normal saline gargles and sniffing normal saline up both nostrils appeared to reduce the number of positive swabs by two, but the data are not quite decisive on this point.

3. With the above treatment the majority of the patients were carriers for periods of less than 9 days.

4. Two successive negative swabs were followed by positive results in 22 cases.

5. In order to recognise 99 per cent, of the carriers in a population receiving treatment with normal saline, five swabs are required from each person examined.

6. Equations are given by which the expected length of run may be calculated for other conditions.
The Influence of raw and Sterilized Milk on Growth and Reproduction in Rats
Authors: Channon Hilda Alice , Channon Harold John
Published: May 2009

1. Groups of young rats have been fed for periods up to one year on a diet consisting of raw or sterilized milk, with a biscuit made from white flour, to which were added supplements of iron, copper and manganese salts. By this method two samples of commercially sterilized milks, prepared by two different processes, have been compared with the corresponding raw milks drawn from the same bulk supplies.

2. At the end of one year the weights of the groups receiving sterilized milks were about 10 per cent, lower than those of the animals receiving raw milks from the same bulk supplies. This finding is similar to that of Drummond (1933) in a study of the relative values of raw and pasteurized milks by the same methods. It is however in considerable contrast to that of Mattick and Golding (1931) who in comparable experiments found that sterilized milk did not adequately support growth.

3. Animals receiving sterilized milks remained in excellent condition throughout the experiment and they could not be differentiated as regards general health from those which received the raw milks.

4. Adequate reproduction occurred on the raw milks, but no litters were reared. Reproduction was less good on the sterilized milks and, as with the raw milks, no litters were reared.

5. The results with the milk prepared by one sterilization process seemed on the whole better than those from the other; but the evidence was not sufficiently conclusive to make this deduction certain.
Notes On The Vi Antigen Of Bacillus Typhosus
Authors: Horgan E. S.
Published: May 2009

1. A peptone salt agar appears to be the medium of choice in the preparation of suspensions of V strains of B. typhosus for Vi agglutination. The presence of heart extract may have a definite inhibitory effect on Viagglutination but the effect is irregular.

2. A safe method for the preparation of anti-Vi serum with virulent cultures is described.

3. Repeated endeavours to produce an anti-Vi serum by the use of formolized vaccines were unsuccessful.

4. A suspension of a V strain killed at 55° C. can be used as a vaccine for producing Vi agglutination.

5. The thermostability of the Vi antigen is discussed.

6. An analysis is made of the presence of Vi antigen in a number of freshly isolated and stock strains of B. typhosus.

7. A series of typhoid cases has been examined for Vi agglutination, and it is concluded that the latter is unlikely to be of any clinical value either in diagnosis or prognosis.

Acknowledgements. The writer wishes to express his thanks to his colleagues, Dr R. M. Humphreys, Senior Physician, Khartoum and Dr J. S. Hovell, Omdurman, for their valuable co-operation; and to Dr Ali Bedri, Khartoum Hospital, he is much indebted for assistance in analysing the clinical data and records of the typhoid cases.
The Incidence Of Weil's Disease In Fish Workers In Aberdeen
Authors: Smith J. , Davidson L. S. P.
Published: May 2009

1. Two hundred and ten blood samples were obtained from workers in the fish trade. Of these, fifty-one, or 24·2 per cent., gave positive sero-reactions in dilutions of the serum ranging from 1/30 to 1/1000.

2. There was no significant difference in the number of positive sero-reactions occurring in male or female workers.

3. In a control series of 406 blood specimens from individuals not engaged in the fish trade, no positive sero-reactions were obtained.

4. Evidence is adduced that leptospiral infections occur in three grades: (a) severe infections associated with jaundice; (b) mild infections with pyrexia and no jaundice; and (c) latent or inapparent infections with no clinical manifestations.

5. Preventive methods have been detailed which, if put into practice, would, it is believed, reduce the incidence of this disease.

6. Sufficient evidence has been produced to show that this disease is occupational in nature, and as such should be scheduled under the Workmen's Compensation Act.

Acknowledgements. We are indebted to Drs Hill, Goldie and Fullerton of the Department of Medicine for much help in the collection of specimens.
Plague Conditions in a Rural Endemic Area of Kenya (Keruguya District, Kikuyu Province)
Authors: Roberts J. Isgaer
Published: May 2009

1. In the introduction, the characteristics of the people are given from the observations of administrative and medical officers well acquainted with the area, fertility of the land and ample rainfall being the main theme of each observation.

2. The topography, climate and local conditions are given, including notes on crop production, habitations, clothing, domestic animals, origin of the people and food.

3. The population figures and rat and human plague figures are discussed. The rat and flea population figures over a twelve month trapping period are given and notes made on interesting biological problems arising out of these figures.

4. The male and female ratios in a Rattus population in plague endemic areas offer an interesting problem for further investigation. It would be instructive to find out what are the factors responsible for high female ratios and the significance of such female dominance being peculiar to endemic areas.

5. The field rodent and flea survey figures are discussed. Although an interchange of fleas takes place between them and house rats, plague remains absent from such communities.

6. There is no evidence to show that there is carriage of infection from endemic centres, either by rats, fleas, merchandise or man.

7. A comparison is drawn between a Kenya endemic centre and an Indian one, similarities and differences being noted. The similarities are that both areas are extremely fertile, large crops of cereals being grown, and the diets of both man and rats are confined to this inadequate source of nourishment. The great differences between Indian and Kenyan endemic centres are the flea species present and that India suffers a much heavier mortality rate in man than does Kenya.

8. It is suggested that the low incidence of plague in man in Kenya is partly explained by the habits of Rattus, which in the typical dwellings of native areas nests in the thatch. Its ectoparasites are then unlikely to come into contact with man. In buildings where rats nest underground contact between its flea (then Xenopsylla cheopis) and man is likely to be very close and constant, and areas containing such buildings are usually distinguished by the epidemic nature of the disease.
Observations upon the bacterial spore nucleus
Authors: Bisset K. A. , Hale C. M. F.
Published: May 2009

Discrete, Feulgen-positive granules, attached to the periphery of bacterial spores, were described by Pietschmann & Rippel (1931), who considered them to be residual cytoplasmic structures; by Stille (1937), who was apparently in doubt as to their nature; and by others, including Robinow (1945), who at first described them as the natural appearance of the spore nucleus. Delaporte (1950) figured the spore nucleus as a less discrete, crescentic body lying against one side of the spore, and in a later study Robinow (1951) accepted this view, and presented evidence to prove that the appearance of the discrete body was an artefact, caused by the hydrolysis with HC1 which was employed in staining. Robinow, in this later study, employed nitric acid instead of hydrochloric acid, and claimed that it gave a truer picture. Both Delaporte and Robinow observed a central, stainable body, which they considered to be cytoplasmic.
Double enteric infection (‘la fièvre typhoïde intriquée’). An account of an epidemic
Authors: Shaw A. Batty , Mackay H. A. F.
Published: May 2009

1. A double enteric infection is defined as the simultaneous infection of an individual or group of individuals with two organisms of the enteric group. The literature of the previously recorded cases and epidemics, in which the diagnosis of double enteric infection has been established by cultural methods, is reviewed.

2. An account is given of a double enteric outbreak of seventy–six cases which occurred amongst British troops and police at Acre, Palestine, in 1948. The infection is thought to have been due to contamination of the water supply with sewage during the civil disturbances. The diagnosis was established bacteriologi–cally in seventy-four cases (93.3%);Salm. typhiwas isolated in forty–three cases,Salm. paratyphiB in three, and bothSalm. typhiandSalm. paratyphi Bfrom twenty–eight cases. There were three fatal cases in the epidemic (mortality rate = 3·94%).

3. The morbidity rate from enteric fever among the infantry unit was 60%, and among the Palestine police, 17%. The possible reasons for this difference is discussed, and the conclusion drawn that it was probably due to the Palestine policemen being older men, with longer overseas service and more 'seasoned' to life in subtropical conditions.

4. Thirteen cases were treated with polymyxin B (15 mg. 4-hourly for 4-day periods); with this small dose no beneficial therapeutic effects were observed, and ten cases showed evidence of renal damage while under treatment.

5. The bacteriology, epidemiology and clinical aspects of double enteric infections are discussed. The diagnosis of a double enteric infection may be established with the greatest certainty by blood culture. Such infections are usually water-borne or milk-borne, and tend to occur when there has been a severe breach of hygiene, e.g. in the contamination of a water supply by sewage. The claim that the prognosis in instances of double enteric infection is worse than with single infections is not supported by the experiences at Acre where the three fatal cases occurred in cases infected withSalm. typhialone.
The 6-hour soluble antigen production test for comparing the infectivity of influenza virus preparations
Authors: Finter N. B. , Beale A. J.
Published: May 2009

1. The 6 hr. soluble antigen production test for comparing the infectivity of influenza virus preparations is described in detail. Dilutions of the preparations are inoculated intra-allantoically into groups of fertile eggs, and after 6 hr. of incubation the amounts of soluble antigen formed in their chorio-allantoic membranes are determined. Reproducible results can be obtained.

2. The similar test, in which haemagglutinins in the chorio-allantoic membranes are measured 6 hr. after inoculation of seed virus, is less accurate and less sensitive.

3. Eggs of different ages of incubation form different amounts of soluble antigen in their chorio-allantoic membranes in 6 hr. when inoculated with the same amounts of virus.
Further studies on the mechanism of mosquito transmission of myxomatosis in the European rabbit
Authors: Day M. F. , Fenner Frank , Woodroofe Gwendolyn M. , McIntyre G. A.
Published: May 2009

Proof of the existence of multiplication of myxoma virus in mosquitoes has been sought by a variety of experiments with Aedes aegypti and Anopheles annulipes. All were completely negative. All features of transmission are compatible with a purely mechanical and none is compatible with a ‘biological’ mechanism.

In mechanical transmission important features of the infected animal host are the number and accessibility of viruliferous skin lesions, and the location and concentration of virus in these lesions.

By inducing mosquitoes to probe through infectious skin lesions and subsequently permitting them to make many successive probes on marked skin sites on the backs of susceptible rabbits, it has been possible to obtain quantitative information on the median minimum virus load of probing mosquitoes, and the rates of loss due to probing and the passage of time.

A preparation of myxoma virus suspended in normal rabbit serum had a half-lifetime of 11 days at 4° C., 5 days at 18–20° C., and 31 hr. at 27–28° C. Apart from losses due to probing (about 12% of the virus load per probe) viable virus on the proboscis of the mosquito probably disappears at about the same rates.
Adsorption of tetanus toxin by brain tissue
Authors: Fulthorpe A. J.
Published: May 2009

The potency of tetanus toxin as measured by combining power is markedly reduced by mixing with fresh or dried preparations of rabbit brain, and by dried horse brain. A number of other bacterial toxins are not so affected.

Tissues other than brain were not found to have this specific effect.

The state of division of the tissue, the time over which adsorption takes place, and the relative proportions of adsorbate and adsorbent affect the quantity of toxin removed. When the quantity of adsorbent and the volume of adsorbate are constant, the quantity of toxin removed per gram of adsorbent is proportional to the equilibrium concentration of the toxin, but not directly so.

Some of the tetanus toxin adsorbed onto fresh or dried preparations of brain tissue can be recovered by washing with physiological saline.

Brain toxin mixtures, when treated with tetanus antitoxin, neutralized an amount of antitoxin about equivalent to the toxin retained by the tissue.

Successive adsorption of tetanus toxin by brain tissue leads to an alteration in the ratio L + per ml./Lf per ml. of the toxin.

The adsorption capacity of brain tissue may be reduced by first washing with tetanus toxoid or heated toxoid or with diphtheria toxoid.
A non-specific complement-fixing system in foot-and-mouth disease and experiments on the absorption of heterologous antibody from serum
Authors: Brooksby J. B. , Erichsen S.
Published: May 2009

Stored mixtures of the virus and corresponding antisera in foot-and-mouth disease have equal complement-fixing activity whether they are prepared from virus and serum of homologous or heterologous types. On ultracentrifugation the complement-fixing activity is removed from the mixture and the remaining antibody is more sharply type-specific in routine complement-fixation tests than the original serum.
The sanitary significance of coliform bacilli in soil
Authors: Randall J. S.
Published: May 2009

Coliforms were readily obtained from many soils. In samples taken from sites exposed to animal contaminationBact. colitype I occurred predominantly. A large number of samples taken from grassy banks, only remotely exposed to contamination, were found to contain intermediates. It was found that the greater the probable degree of contamination of the soil the higher was the proportion ofBact. colitype I, and that the less the probable degree of contamination the higher was the proportion of intermediates. It is difficult to explain this merely on the basis of the prolonged survival of intermediates in soil, and it would appear obvious that the source of these intermediates lay elsewhere than in animal faeces. The numbers in which they were found in soil, however, were not of the order expected of bacteria living in their natural environment, and consequently it was equally difficult to conclude that these intermediates were actively established in soil.
The Isolation of Salmonella Organisms from Fresh Fish Sold in a Colombo Fish Market
Authors: Gulasekharam J. , Velaudapillai T. , Niles G. R.
Published: May 2009

Of 629 fresh fish (sixty-five species) and forty-two samples of fish-washings obtained from a fish-market in Colombo, and investigated bacteriologically for the presence of Salmonella, thirty-nine fish (twenty-four species) and five samples of washings were found to be harbouring the organisms.

Of fifteen salmonella types found, all except Salm. chittagong and Salm. oranienberg had been previously isolated from human and animal sources in Ceylon.

The presence of Salmonella in the intestines of fresh fish examined suggested that the organisms had entered the live fish, whilst their isolation from the gills and fish-washings was evidence that the fish could have been contaminated post-mortem.

The significance of these findings in relation to hazard to health is discussed.
Clinical and subclinical variola minor in a ward outbreak
Authors: de Salles-Gomes Luis F. , Angulo Juan J. , Menezes Ernaldo , Zamith Vinicio A.
Published: May 2009

A variola minor outbreak in a 36-bed hospital-ward comprised seven cases of overt variola after the first case. Clinical and epidemiological findings were typical, seven of the eight cases of overt variola being confirmed by virus isolation or antibody titrations. In addition, thirteen definite and seven possible instances of subclinical variola were deduced from complement-fixation or haemagglutination-inhibition tests. A discussion is made of the validity of serological criteria of variolous and vaccinial infections.
The immunization of mice, calves and pigs against Salmonella dublin and Salmonella cholerae-suis infections
Authors: Smith H. Williams
Published: May 2009

1. Antisera prepared in rabbits or calves against live Salmonella dublin gave mice some degree of protection against oral infection with this organism. Both antiserum prepared against heat-killed S. dublin and dead vaccines prepared in a variety of ways produced little or no immunity.

2. A rough variant of S. dublin of low virulence for mice, no. 17 A, produced a reasonably good immunity against oral infection with S. dublin in mice but not in calves. Mice that survived injection with another rough variant that possessed a considerable degree of virulence for these animals, no. 51, were immune to oral infection with S. dublin. Experimentally and naturally, this variant and, to a lesser extent, 9S, a smooth variant of S. gallinarum of reduced virulence, produced an appreciable degree of immunity in calves against S. dublin infection; none of the calves injected with these variants showed any signs of ill-health as a result.

3. Two rough variants of S. cholerae-suis, nos. 3 and 6, possessed a considerable degree of virulence for mice; those that survived were resistant to oral infection with S. cholerae-suis. Experimentally and naturally, both variants produced an appreciable degree of immunity in pigs.

4. Mice that survived vaccination with the rough S. cholerae-suis variant no. 6 were resistant to oral infection with S. dublin. Those that survived vaccination with the rough S. dublin variant no. 51 were resistant to oral infection with S. cholerae-suis and S. typhi-murium; they were fully susceptible to parenteral administration of Escherichia coli and Erysipelothrix rhusiopathiae.

5. Vaccination with S. cholerae-suis variants 3 and 6 and S. dublin variant 51 provoked the formation of H but not O antibodies. These variants were never found to mutate from rough to smooth in vitro or in vivo.
Viruses in acute respiratory infection in a general community
Authors: Banatvala J. E. , Anderson T. B. , Reiss B. B.
Published: May 2009

The aetiology of acute respiratory infections between September 1962 and August 1963 was studied in two general practices in Cambridge. These practices were reasonably representative of the permanent community of Cambridge.

There were 592 spells of acute respiratory infection in the combined practices, representing an incidence of 11·4 spells per 100 persons. Children aged 0–4 had the highest rates (51·6 spells per 100 persons).

It was possible to establish a diagnosis in 62·5% of cases investigated. Influenza and parainfluenza infections featured prominently, being responsible between them for 46·6% of all respiratory infections investigated. From September 1962 to January 1963, parainfluenza viruses were prevalent, causing acute laryngo-tracheo-bronchitis in children (croup), and an influenza-like illness in adults. From February to April 1963, influenza A (Asian) was epidemic, a clinical diagnosis of influenza being frequently confirmed by laboratory studies at this time. There were nine cases of Eaton agent infection, seven of which had PAP, the other two being family contacts who later developed influenza-like illnesses.

Adenovirus (four cases), and RS virus (three cases) were not prevalent to any large extent in Cambridge during the survey.
Estimating titres and their approximate standard errors in complement fixation tests
Authors: Elston R. C.
Published: May 2009

A method is given for obtaining the approximate standard error of the anti-serum (or antigen) maxima titre in the complement fixation test when the maxima line is determined by only two points; the same formulae may be used to obtain a conservative estimate of the standard error when more than two points are available. If the degree of lysis in each reaction mixture can be scored more finely than into the three simple states of ‘no lysis’, ‘partial lysis’ and ‘complete lysis’, then more accurate estimates can be obtained. A method is also given for estimating the concentration of one antiserum (or antigen) relative to that of another when they react homologously.
A comparative study of a plaque and quantal method for assaying the neutralizing activity of antisera to type 1 poliovirus
Authors: Higgins P. G.
Published: May 2009

Sera from two rabbits bled after one, two and three inoculations of concentrated type 1 poliovirus tissue culture fluid were assayed for neutralizing activity by a quantal and a plaque method. The plaque counts in these tests have been shown to approximate to a Poisson distribution as determined by the relationship between the variance and the mean of replicate counts. However, there is a considerable scatter of the points in such a comparison and this accounts for the absence of the expected increase in accuracy of this plaque method over the quantal.

The relationship between the antibody content of the sera determined by the two methods is non-linear. This can be attributed to inhomogeneity of the antibody produced which increases with the number of antigenic stimuli given.