bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experiments on adaptive variation and rejuvenation:Bacillus dysenteriaeFlexner, grown on media containing sulphanilamide, acriflavine, argyrol, neosalvarsan and no drug
Authors: Stewart F. H. 
Published: May 2009

Bacillus dysenteriaeFlexner(Shigella paradysentriae)grown on Lemco agar plates (without peptone) containing sulphanilamide 1/20,000 to 1/10,000 forms papillae which on subculture yield two strains: (1) the original strain unmodified and (2) a strain resistant to SA.The latter has arisen by discontinuous variation. There are no forms intermediate between strain (1) and strain (2).In one such case (Exp. 1, p. 334) the no-contact race, the unmodified non-resistant strain from the primary sulphanilamide plate and the resisting variant strain were titrated in broth containing sulphanilamide in ten increasing concentrations from 1/34,000 to 1/5000. The first two strains, the no-contact and the unmodified non-resistant from the sulphanilamide plate grew in SA 1/34,000 and failed in 1/21,000, while the resisting variant grew up to the tube containing SA 1/6000 and failed to grow in 1/5000.On plates containing sulphanilamide this adaptive variation takes place only in the papillae. It can also take place in broth containing, for example, SA 1/20,000 to 1/10,000.There is no such thing as gradual progressive acquisition of resistance by the whole of a bacterial population exposed to a drug. Such phrases as ‘teaching bacteria to resist’ are misleading and anthropomorphic and should not be employed.Fluid cultures which show a progressive gradual increase of resistance do so as a result of an increasing percentage of resistant cells in a mixed population of resistant and non-resistant bacteria. Experiments in fluid media should always be checked and the growth analysed by plating.Resistant strains maintain this character after prolonged growth on drug-free media.(2) Flexner's dysentery bacillus grown on plates containing acriflavine 1/60,000 to 1/40,000 forms in papillae strains resistant to this drug. The non-papillary areas of colonies die early, viz. on the 3rd day. The variation in this case also is discontinuous.(3) On the other hand, if Flexner's bacillus is grown on agar containing organic compounds of silver or arsenic (argyrol or neosalvarsan), it forms no variants resisting these drugs.(4) Papillae possess two biological functions:(a)they are the site of adaptive variation in response to elements in their environment, such as harmful drugs or useful sugars; (6) they are also the site of rejuvenation of senile cells and of cells affected by common unfavourable conditions such as exhaustion of food supply and accummulation, of excretory substances.The greatest development of papillae takes place on plates which form no variants, such as plates of drug-free agar, agar plates containing sulphanilamide sown with strains resistant to sulphanilamide and plates containing organic compounds of silver or arsenic.
The survival of foot-and-mouth disease virus in meat and offal
Authors: Henderson W. M. , Brooksby J. B. 
Published: May 2009

Quantitative studies have been made of the survival of foot-and-mouth disease virus in beef and beef offals after storage at temperatures employed in the imported-meat trade.The survival of virus is closely associated with the hydrogen-ion concentration of the tissue; thus the acidity of rigor mortis of muscular tissue rapidly causes inactivation. Quick-freezing of beef suspends acid formation and active virus was demonstrated for so long as the meat was kept frozen.Thawing of quick-frozen meat initiates the suspended acid formation at an accelerated rate and rapidly produces a medium unsuitable for virus survival.Liver, kidney, rumen, lymph node and blood from diseased cattle have all been shown to be highly infective and to remain so if stored frozen. Acid formation in these tissues and in blood is not on the same scale as in muscle, and prolonged survival of virus is more likely even with delay in freezing and after thawing. This remains true of lymph node and of residual blood in vessels of a carcass in which the development of rigor mortis is complete.Feeding of infective offal to swine under experimental conditions resulted in the appearance of the disease.The significance of these observations is discussed in relation to the distribution of these products constituting a risk of spreading foot-and-mouth disease.We are indebted to Dr Ian A. Galloway, Director of this Institute, Mr L. B. A. Grace, Chief Technical Adviser on Meat Inspection of the Ministry of Food and Mr R. Bremner, Chief Executive Officer of the Meat Importers' National (Defence) Association, Ltd., for their help and advice while this work was in progress.It is a pleasure to acknowledge the technical assistance of Mr W. J. Brownsea.
The Antibody Response in Man Following Infection with Viruses of the Pox Group III. Antibody Response in Smallpox
Authors: Downie A. W. , McCarthy K. 
Published: May 2009

From 117 cases of smallpox 140 sera have been examind for antihaemagglutinin, for complement-fixing and for variola-neutralizng antibody.In smallpox patients who had not been vaccinated prior to infection, variola-neutralizing antibody and vaccinial antihaemagglutinin were present in all sera examined after the sixth day of illness. Complement-fixing antibody was not found until the eighth day of illness but was present in all examined after the ninth day.In previously revaccinated smallpox patients variola-neutralizing antibody was present in all sera examined after the third day of illness and antihaemagglutinins in all after the fourth day. Complement-fixing antibody was present by the seventh day and was found in all sera examined after the ninth day. Not only did antibody in general appear earlier in previously vaccinated smallpox patients but the titres were generally considerably higher. In ten fatal cases antibody titres were low except in two in whom the level of variola-neutralizing antibody was quite high—in one case on the second day and in the other on the fourth day of illness.In six variola contacts, who suffered febrile attacks without rash, antibody studies indicated the variolous nature of their illnesses. In these and other atypical smallpox infections, when laboratory confirmation of clinical diagnosis is only requested at a late stage of the disease, a high titre of antibody, particularly complement-fixing antibody, may enable a firm diagnosis to be made.We wish to acknowledge our indebtedness to Dr W. H. Bradley of the Ministry of Health; Dr E. C. Benn of Seacroft Hospital, Leeds; Dr D. C. Liddle of Monsall Fever Hospital, Manchester; Dr E. R. Peirce of Liverpool and other Medical Officers for information concerning smallpox patients. Our thanks are also due to Dr F. O. MacCallum of the Virus Reference Laboratory, Colindale, who kindly sent us sera from some of the cases in the 1950 smallpox outbreak in Brighton.
Recurrent staphylococcal infections and the duration of the carrier state
Authors: Roodyn Leonard 
Published: May 2009

An investigation has been carried out over a period of 7 years of a series of eighty-one patients who first presented in 1951–52 with staphylococcal lesions. In seventy-two oases (89%) the infection was limited to a single, short episode of infection without recurrence. But nine patients (11%) developed recurrent lesions throughout the period. In these patients, from a comparison of the phage types isolated from successive infections, it was inferred that the organism had persisted in the body for over 6 years in two cases, for 4–5 years in five cases and for 1·3 years in three cases.Nasal carriage also persisted for over 6 years in two cases and for 3–5 years in three cases.In two cases, chronic skin carriage occurred in the absence of nasal carriage. There was persistence of staphylococci for 3 and 5 years in these cases, and the use of a special technique revealed that carriage in the deeper layers of the skin was particularly important.The frequency distribution of phage patterns isolated in recurrent cases reflected the high incidence of Group II strains at the time when the strains were first acquired. New infections which arose in 1957–58 no longer showed this preponderance of Group II strains, as only eleven (28%) of thirty-eight new infections were caused by this group.The bacteriological examinations were mostly carried out by the Central Public Health Laboratory, Colindale, and I wish to express my gratitude to Dr R. E. O. Williams of the Staphylococcal Reference Laboratory, for his assistance in this work. I am also grateful for the laboratory facilities afforded me by Dr Ridley at the Hospital for Tropical Diseases for the performance of the skin carriage testing.
The effect of feeding pigs on food naturally contaminated with salmonellae
Authors: Smith H. Williams 
Published: May 2009

1. The course of events following the feeding of salmonella-free pigs on food naturally contaminated with salmonellae has been followed. The pigs were killed at varying times after the commencement of the experiment and their organs examined for salmonellae.2. None of the pigs showed any signs of ill-health and no pathological lesions were observed in them when they were killed. Salmonellae were found, however, in very small numbers in the mesenteric lymph nodes of some of them but not in any of their other internal organs or in their muscular tissue. The longer the pigs were fed on the contaminated food the more likely were their mesenteric lymph nodes to be infected.3. Salmonellae were isolated from time to time from the faeces of the pigs but there was no suggestion of any of the pigs becoming permanent faecal excreters of these organisms.4. Six pigs were retained for a short time after the use of the contaminated food was discontinued. Salmonellae were never found in their faeces and when they were killed the mesenteric lymph nodes of only one of them was found to be infected.5. The results are discussed from the agricultural and public health viewpoints.
A study of tetrathionate enrichment techniques, with particular reference to two new tetrathionate modifications used in isolating salmonellae from sewer swabs
Authors: Jameson J. E. 
Published: May 2009

Either triplicate or paired sewer swabs put down at sixty manholes were examined after 24, 48 or 72 hr. periods of enrichment at 37° C. in a standard tetrathionate medium (medium C) and in two new tetrathionate modifications—medium A being a combination of tetrathionate broth and ingredients of Wilson and Blair's medium, and medium B similar but containing only half the amount of the Wilson and Blair's ingredients, and in addition 1% sodium lauryl sulphate.Salmonellae were isolated from thirty-nine sites: there were three double isolations of salmonellae.The richest growths of salinonellae were obtained from medium B and the poorest from medium C. Medium C however yielded more isolations from the smaller sewers than medium B: the converse held true in the trunk sewers.An optimal 48 hr. enrichment time for sewer swabs was demonstrated in the case of medium A. No optimal time was found for either of the other two media. Platings at the optimal enrichment time from medium A yielded more salmonella isolations than the combined 24 and 48 hr. platings from medium C.
Immunization against tetanus
Authors: Suri J. C. , Rubbo Sydney D. 
Published: May 2009

1. A study of the various aspects of passive tetanus immunization and combined active and passive immunization in different animal species has been undertaken.2. The criteria on which conclusions have been based consisted of titration of antitoxin serum levels and mouse and guinea-pig protection tests using a challenge of 20 M.L.D. of tetanus toxin.3. A study of the rate of elimination of heterologous tetanus antitoxin in normal and sensitized animals showed that the latter eliminated antitoxin more rapidly from circulation after subcutaneous injection but no difference could be detected following intravenous administration. More important is the profound loss of serum antitoxin in both animal groups from the seventh day onwards.4. The rate of elimination in humans receiving 1500 units of horse antitoxin subcutaneously was approximately the same in normal subjects and those who had been previously exposed to horse serum.5. The interference of an active primary immune response by the simultaneous injection of antitoxin in rabbits was consistently more marked with fluid toxoid than with adsorbed toxoid. Thus, combined active and passive immunization of persons who have never been actively immunized, is not recommended, especially with fluid toxoid.6. Administration of adsorbed toxoid 7 days or more after passive immunization with heterologous antitoxin does not interfere with the primary immune response.7. Comparison of the immunizing potency in rabbits of fluid and adsorbed toxoids showed that the latter was far superior.8. Homologous antitoxin was demonstrated in man and animals to be immunologically superior to the heterologous type in every respect. It persisted unchanged in a therapeutically active concentration for at least 3 weeks in humans and its protective action in guinea-pigs was at least 100 times greater than heterologous antitoxin. Since homologous antitoxin can be used in low doses it will not interfere with the primary immune response in combined immunization.9. A recommended prophylactic dose of homologous antitoxin for man would be 200–250 units.
Studies in the epidemiology of infectious myxomatosis of rabbits: VIII. Further observations on changes in the innate resistance of Australian wild rabbits exposed to myxomatosis
Authors: Marshall I. D. , Douglas G. W. 
Published: May 2009

1. In one Australian study area where the selection pressure of annual epizootics of myxomatosis has been extremely high, the innate resistance of the rabbits was found to have increased to such an extent that only 26% died when inoculated with a strain of myxoma virus which kills 88% of genetically unselected rabbits.2. The level of innate resistance in a rabbit population varies with the total experience of the disease.3. In combined field and laboratory trials it was shown that the mortality rate in the field is influenced by innate resistance at least as much as under the sheltered conditions of an animal house. The effect was apparent with both an attenuated and a highly virulent strain of virus.4. The moderately high ambient temperatures during the field experiments probably contributed to the sparing effect.
Airborne micro-organisms: survival tests with four viruses
Authors: Harper G. J. 
Published: May 2009

Airborne virus particles of vaccinia, influenza, Venezuelan equine encephalomyelitis, and poliomyelitis have been tested for viable survival in the dark at controlled temperatures and relative humidity (R.H.) for up to 23 hr. after spraying.Viable survival at each R.H. level was better at lower temperature than at higher temperature. Poliomyelitis virus showed best survival at high R.H.; the other three viruses survived best at low R.H.
Some observations on the use of the Ouchterlony gel diffusion technique in the study of myxomatosis
Authors: Chapple Paul J. , Bowen E. T. W. , Lewis N. D. 
Published: May 2009

1. Laboratory rabbits were infected with seventeen different preparations of myxoma virus (this probably represents thirteen strains of which four could be classified as fully virulent and the rest as attenuated, two being markedly so).2. One hundred and twenty-four wild rabbit carcasses were obtained from a rabbit infestation in the throes of an outbreak of myxomatosis.3. All the carcasses were examined for the presence or absence of myxoma antigens and antibodies by a modified Ouchterlony gel-diffusion precipition test.4. As a result of (3), we have concluded that the gel test can provide confirmation of the presence or absence of myxomatosis. It is particularly useful in cases of doubt about the clinical diagnosis. The test can also give a reasonable indication of the number of recovered rabbits in a population and, more important still, it can give an indication of the recovery rate during an outbreak of disease. However, attempts to differentiate between fully virulent and attenuated strains of virus were unsuccessful.
Intradermal cholera vaccination
Authors: Noble J. E 
Published: May 2009

The protection afforded by cholera vaccine administered by the intradermal route, and demonstrated by active and passive mouse protection tests, active guinea-pig protection tests, and agglutination titres, is excellent and equal to that given by subcutaneous inoculation.It is suggested that cholera vaccine administered by the intradermal route would greatly reduce the incidence of reactions which occur when the vaccine is given subcutaneously.
Hybrids derived from the viruses of variola major and cowpox
Authors: Bedson H. S. , Dumbell K. R. 
Published: May 2009

The characterization of 16 clones of virus derived from mixed infections with variola major and cowpox has been described. This work has involved the description of the plaques produced by variola major in chick embryo monolayers, and a more detailed study of the effects of raised temperature on pock production by pox viruses on the C.A.M.Two of the variola major—cowpox clones were found to correspond to cowpox virus, while the other 14 shared various combinations of parental characters. Among them there were 10 distinct new types of virus. Evidence of the stability of these viruses has been presented.Analysis of the combination of characters encountered among the hybrids has given good evidence that all the eight marker characters used segregate independently. A particular instance of this was the character of chick embryo virulence which, among the hybrid viruses, was shown to be unrelated either to ceiling temperature or speed of plaque formation.The significance of these findings in relation to the general problem of virulence has been briefly discussed. The possibility that vaccinia may have originated as a hybrid of variola and cowpox has lso been considered.
Interferon production and sensitivity of Semliki Forest virus variants
Authors: Finter N. B. 
Published: May 2009

Semliki Forest virus was passaged 10 times in series in calf kindly cells, starting with virus passaged in the mouse brain (MB virus). A variant was obtained (termed CK virus). The two viruses were antigenically indistinguishable. When grown on L cells, CK virus formed smaller plaques than MB virus. In parallel growth curve studies in calf kidney cells, a small inoculum of CK virus grew more rapidly and to a higher final titre than a comparable inoculum of MB virus, and usually stimulated production of less interferon. Pre-treatment of cells with calf interferon reduced the growth of both viruses, but especially that of MB virus. The results are considered in relation to the phenomenon of virus adaptation. It is suggested that such differences between the two variants in their relative sensitivity to and production of interferon could have played a part in the emergence of CK virus as the predominant type during serial passages in calf cells.I wish to thank Mr H. Moores and Mr R. Sims for skilful technical assistance.
The campaign against typhoid and paratyphoid B in western Norway. Results of cholecystectomy
Authors: Vogelsang Th. M. 
Published: May 2009

1. The first chronic carrier in western Norway was discovered in 1918. Since then 147 individuals have been found to be chronic carriers, 84 being carriers of S. typhi and 63 of S. paratyphi B.2. Of the 147 chronic carriers 23 were males and 124 females. Most of the carriers were elderly folk, 96 over the age of 50 and 37 over the age of 70 when their carrier state was discovered. There is a considerable rise in the incidence of gall-stones among women around the age of 50, while a similar rise comes at a higher age in men. This sex difference may be a contributory cause of the larger number of female carriers.3. Operations were performed on 66 chronic carriers with a view to curing the carrier state. In 2 cases, only cystotomy could be performed because of the state of the gall-bladder. In one of these the carrier state was cured, while it persisted in the other.4. The gall-bladders of 64 chronic carriers were removed by operation with the following results: 2 died as a result of the operation, 9 remained carriers, and 53 are considered cured. The operation was therefore successful in four-fifths of the cases.The gall-bladders of 2 individuals who remained carriers were found at operation to be sterile and perfectly normal, without stone formation. Two other individuals who remained carriers have later died, 1½ and 7 years after their operations. In both cases S. paratyphi B was cultivated from the common bile duct and the hepatic duct. The specific process may therefore in a few cases be situated at a higher level in the bile passages of the liver.5. The interval between infection and operation varied from 3 months to 50 years. The 2 carriers who had the longest interval are both cured.6. Indications for operation are given on the basis of the experiences provided by the present material.
An improved formate lactose glutamate medium for the detection ofEscherichia coliand other coliform organisms in water
Authors: Gray R. D. 
Published: May 2009

A chemically defined fluid medium—improved formate lactose glutamate—is described of which the cost is less than a quarter that of standard MacConkey broth and which is at least equally suitable for routine bacteriological examination of water. It has actual advantages in that the medium after fermentation is clearer and that, therefore, acid and gas production is more easily seen; moreover more isolations of both coliform bacteria and ofEsch. coliare obtained with fewer false positive reactions. Trials with a solid version of the medium suggest that the relative freedom from false positive reactions arises from the failure of the medium to growCl. welchii—one of the commonest causes—and enterococci, another suspected participant. In fact, without any inhibitory agent the medium appears to be virtually specific for the coliform group and particularly favoursEsch. coli.It remains to be seen whether certain aerobic spore-bearers found from time to time in surface waters may, to some slight extent, interfere with the almost complete specificity so far discovered.The medium is recommended in place of MacConkey broth and other peptonecontaining media, not only for the prospect of better results, in that suppression of the coliform group does not occur, but also for cheapness and for freedom from the inevitable variability associated with media incorporating peptone and, particularly, bile salt. It is hoped that this medium will shortly become available commercially in dehydrated form at a price still considerably less than that required to make up MacConkey broth from its constituents.Some labour-saving curtailments in the routine of water examination are also suggested.It is hoped not only that the fluid medium will supplant MacConkey broth for the dilution method of water analysis but that the solid medium, without material alteration, will also prove suitable for water examination by membrane filtration.I am deeply grateful to my laboratory staff, particularly Mr J. H. Evans, F.I.M.L.T., and Mr G. H. Lowe, F.I.M.L.T., for undertaking so much of the work when routine work was particularly heavy, and for many valuable suggestions. My thanks in addition are due to Mrs Peggy Johnson and Mrs Marilyn Childs, who made up the medium, and also to the directors of the participating P.H.L.S. laboratories not only for having the work carried out but for helpful comments.