bluuebunny/crossref_metadata_2025_split huggingface dataset:
Typhoid carriers and Vi agglutinins
Authors: Pijper Adrianus , Crocker Clarice G. 
Published: May 2009

Seven more carriers, all possessing appreciable quantities of Vi agglutinins, are added to those already known.Vi agglutination tests performed on 2526 inhabitants of the Transvaal, both native and white, showed that 5·3 % had similar quantities of Vi agglutinins.A fair number of these positive reactors were further examined for the presence of typhoid bacilli in their excreta, but the number of positive findings was very small.It is argued that there are a large number of typhoid faecal carriers who are such minimal excreters that the typhoid bacilli in their stools escape detection.We wish to thank Dr T. Lötter, Acting Medical Officer of Health of Pretoria, and his staff, for their kindly help in collecting the material for this paper. Our special thanks are due to Lieut.-Col. H. Nelson, Medical Officer of Health of Pretoria, now on active service, for his never-failing interest in our work which has been such a great encouragement.
Haemolytic streptococci in the dust of hospital wards, and their relationship to infection: A report to the Medical Research Council
Authors: Edward Derrick G. ff. 
Published: May 2009

1. A weekly examination for haemolytic streptococci was made of the dust of two hospital wards; observations lasted in each ward for about six months. The wards chosen were a combined ear, nose and throat and eye ward used for adult patients, and a children's ward.2. It was found that on an average for the whole period the dust of the former ward contained 300,000 haemolytic streptococci per gram and the dust of the latter 250,000 per gram.3. Representative colonies of haemolytic streptococci grown from each sample of dust were examined serologically to determine their group. About 33% of those isolated from the E.N.T. Eye ward were group A and about 80% of those from the children's ward.4. In order to determine the relationship of the streptococci in the dust to streptococcal infection among patients and staff, throat swabs and swabs from septic lesions were regularly examined.5. In the children's ward 27·8% of 270 patients were found to be infected with haemolytic streptococci either on admission or at some time during their stay in hospital. The incidence of infection acquired in hospital was more than 12·2%. About two-thirds of these infections were latent.6. Group A streptococci isolated from the dust and swabs were identified serologically according to type. It was noted that the occurrence of a particular type in the dust often resulted from the presence of one or more infected persons in the ward.7. It was, however, frequently noted that a particular type made its first appearance in the dust when it could not be cultured from any of the swabs. It is possible that these strains were introduced to the ward by visitors, such as patients' relatives and friends or patients from other wards coming for septic dressings.8. No conclusive example of a hospital cross-infection conveyed by dust was noted.I wish to thank Dr T. J. Hennelly and Dr D. G. Morgan, Medical Superintendents of the two hospitals, for giving me the facilities to carry out the investigation; also Dr S. T. Crowther and Dr Duncan Davies, and the sisters and nursing staff for their assistance and co-operation. I am especially indebted to Dr V. D. Allison for his helpful advice and criticism.
Studies in the dynamics of disinfection: I. New data on the reaction between phenol andBact. coliusing an improved technique, together with an analysis of the distribution of resistance amongst the cells of the bacterial populations studied
Authors: Jordan R. C. , Jacobs S. E. 
Published: May 2009

1. The action of phenol onBact. colihas been studied quantitatively in detail under such conditions that unfavourable circumstances other than the presence of the germicide were as far as possible eliminated. Briefly, this involved the addition of phenol solution directly to a large volume of culture developed under rigidly standardized conditions.2. When the mortality exceeded 95% the variation between the numbers of colonies on replicate plates, when determining the numbers of survivors, was often excessive.3. Under the conditions used the death-rate was not constant. First, there was a phase (1) of slow but increasing death-rate which merged gradually into a phase (2) of approximately constant rate which was also the maximum for a given phenol concentration. There are indications that the death-rate may decline towards the extreme end of the disinfection process.4. The virtual extinction time (the time taken for the survivors to fall to 1 per ml. as determined by extrapolation of the log survivors-time curve) increased as the phenol concentration decreased, as also did the duration of phase 1. The latter occupied about 60% of the virtual extinction time when the concentration was 3·48 g. phenol per 1., but with rising concentration its duration decreased at a greater rate than the virtual extinction time so that at about 7 g. per 1. phase 1 was very short though still detectable. The standard errors of the virtual extinction times varied between ± 1·5% and ± 5·43%.5. Using the probit method it has been shown that at low concentrations of phenol the distribution of resistance ofBact. coliis approximately normal when the resistance is measured in terms of the survival times.6. The distribution of resistance was found to be normal at all concentrations of phenol used, when that resistance was measured in units of the logarithms of the survival times, with the exception that at the lower concentrations there was a sudden change in the slope of the probit-log survival-time line at about 20% mortality. This change became less marked with rising concentration and was probably absent at 8·00 g. phenol per 1.7. After conversion into the dosage-mortality form, the data reveal that about 70% of the cells show an approximately normal distribution of resistance when the latter is expressed in terms of the dosage survived for a fixed time, provided that the exposure time is less than 50 min.8. The distribution tends to be normal for longer exposure times when the resistance is measured in terms of the logarithms of the dosages survived. On this basis a change of slope of the probit-log dosage line is observed as in the case when resistance is measured in terms of the logarithms of survival times.
Revaccination as a measure of immunity to smallpox
Authors: Horgan E. S. , Haseeb Mansour Ali 
Published: May 2009

1. Serological methods for the determination of smallpox immunity are briefly discussed, and it is concluded that they are unlikely to provide a diagnostic method of sufficient accuracy.2. Experimental work is recorded which shows certain differences in the response of previously vaccinated individuals, revaccinated simultaneously with a standard vaccine lymph and an elementary body suspension (vaccinia) of high potency. The significance of these differences is discussed.3. The results indicate that although the advantage of the e.b. suspension over vaccine lymph is relatively insignificant, that of two insertions over one is very marked. In revaccination the routine use of one insertion only may result in a certain number of semi-immunes (vaccinoids) being erroneously reported as immunes.4. It is concluded that if the two insertion technique be practised, persons showing immune reactions (negatives) may be considered, in all probability, as possessing full immunity to vaccinia-variola virus.
Some bacteriological aspects of dehydrated foods
Authors: Haines R. B. , Elliot E. M. L. 
Published: May 2009

1. Data on the maximum temperatures of growth of certain organisms, on the rate of toxin production byCl. botulinumand the rate of multiplication of certain Salmonellas, is given, as a basis on which to define the time and temperature of dehydration in the preparation of dehydrated foods.2. It is concluded that 50° C. is the minimum temperature below which dehydration should not be carried out. Where some heating below this temperature is unavoidable, the period of such heating should not exceed 4 hr.3. Data on the microbial changes in dehydrated foods equilibrated at various humidities indicate that bacterial growth is not expected below about 15 % water content. Some experiments on the death of bacteria at water levels below this are discussed.4. Details are given of the general bacteriological examination of the process of dehydration on a commercial scale for dried soup, dried minced beef, dried carrot, cabbage and potato.This work was carried out under the joint auspices of the Food Investigation Board of the Department of Scientific and Industrial Research, and the Ministry of Food, and is published by permission. The authors are indebted to Professor H. R. Dean for the provision of facilities, and to him, Professor G. S. Wilson, Dr A. W. Downie, and various other members of the Emergency Public Health Laboratory Service for help and advice.
A standardized method of disinfecting infected blood-clots
Authors: Gardner A. D. 
Published: May 2009

1. A method is described for estimating the disinfecting power of chemical substances on small cylindrical blood-clots of standard dimensions (about 1·5 mm. in diameter) containing a measured number of bacteria (Staph. aureus). It is capable of giving guidance for the use of disinfectants under the described conditions.2. No practicable disinfectant regularly sterilized heavily infected clots (400,000 cocci) in 5 min. at 17–20° C.3. In 30 min. the following were the only substances that were uniformly successful with heavily infected clots: 2·5% iodine in aqueous KI solution; 50% Chloros, containing about 5% chlorine; 70% alcohol containing 0·1% acriflavine. (The first of the three was tested on a larger scale than the others, and its potency is therefore the more firmly established.)4. Reduction of the number of cocci in the clot increased the range of effective disinfectant solutions. Thus with 4000 cocci per clot regular clot disinfection was achieved in 30 min. with the following additional solutions: ethyl alcohol 70 and 50%; Chloros 25%; phenol 2·5% and lysol 1·25%. A few tests indicated that Zephiran (and probably CTAB) at 1 or 2% concentration would also pass this less exacting test.
Bacterial infection and immunity in lower vertebrates and invertebrates
Authors: Bisset K. A. 
Published: May 2009

A review is given of some of the literature concerned with bacterial infections and immunity in invertebrates and cold-blooded vertebrates. Among the former, insects have been most fully studied, although a certain amount is known of the immunological reactions of marine invertebrates. Diseases of insects are mainly generalized, bacteraemic conditions, and the great majority are caused by Gramnegative cocco-bacilli. Diseases of cold-blooded vertebrates also are usually generalized, but bacteria from a very wide variety of groups have been isolated from them.It is probable that this resemblance in the infections of these widely separated groups of animals is due to the fact that, unlike mammals and birds, with whose reactions we are more familiar, the regulation of their temperature and the constitution of their body fluids is not exact. This toleration of wide variations of their own physical and chemical constitution must reduce their sensitivity to the changes produced by infection, and hence decrease the likelihood of a local reaction, designed to confine the invading organism to the immediate region of its point of entry, i.e. a local inflammation.The production of humoral antibodies appears to be almost universal in the animal kingdom, although greatly affected by changes in temperature.The effect of temperature upon the balance between host and parasite is also discussed. This question bears upon the problem of occasional pathogenesis by saprophytes. Even among mammalian pathogens the borderline between parasite and saprophyte is an indistinct one, especially in such cases asProteusandPseudomonas pyocyanea, and even those species which are usually regarded as exclusively parasitic may readily be constrained to adopt a saprophytic existence on artificial culture. Where cold-blooded animals are concerned the boundary is even more difficult to draw, and it is possible that under suitable conditions, bacteria which are normally saprophytes may be capable of causing infection. This point will be impossible of proof until more sensitive means of definition of bacterial species are discovered.
Studies in the dynamics of disinfection VIII. The effect of lethal temperatures on standard cultures ofBact. Coli.I. A detailed analysis of the variations of death-rate with time
Authors: Jordan R. C. , Jacobs S. E. , Davies H. E. F. 
Published: May 2009

1. Whole cultures ofBact. coligrown under carefully controlled conditions have been subjected to the action of heat at temperatures ranging from 47 to 55° C. and the survivor curves determined.2. The occurrence of excessive variation between replicate plates of counts made when the mortality exceeds 95 % was very much less evident than when phenol was the lethal agent.3. At temperatures of 35° C. and below, disinfection of the cultures was never complete, as a permanent population of cells became established. In some cases the numbers of heat-resistant cells reached nearly 0·01 % of the original population, but great fluctuations were observed.4. The death-rate during the active part of the disinfection was not constant but, in general, increased with time. In the faster disinfections this increase was difficult to detect and the logarithmic death-rate appeared to be virtually constant, but the increase is nevertheless believed to have been present in all cases.5. The data for all the experiments have been combined to give a composite disinfection curve from which it was concluded that the death-rate was low at first but rose to a maximum at which it remained constant until the mortality had reached at least 99·99%.6. This finding led to the decision to treat all the experiments as if the regression of log survivors on time had been linear between mortalities of 90 and 99·99%. The standard errors of the calculated regression coefficients were small, so that this method of treating the experimental data appears to be justified.The authors wish to express their gratitude to Messrs I.C.I. (Pharmaceuticals) Ltd. for their valuable financial assistance, which has enabled one of us (H. E. F. D.) to devote his full time to this work.
Nasal filtration of airborne droplets
Authors: Boyland E. , Gaddum J. H. , McDonald F. F. 
Published: May 2009

Apparatus for determination of the penetration of particulate airborne material through the nose is described. The penetration of aerosols of liquid particles produced by a spray has been measured in rats, rabbits, goats, sheep and men. The penetration decreased with increase in the rate of flow through the nose.Particles of the order of I μ diameter penetrate the nose at all rates of flow, while very few particles larger than 15 μ can penetrate except at low rates of flow.
Phage-resistant and phage-carrying strains of lactic streptococci
Authors: Hunter G. J. E. 
Published: May 2009

1. The types of resistance acquired by certain related strains of Str. cremoris as a result of phage action were investigated.2. Some partially resistant forms of Str. cremoris were able to ‘carry’ phage in symbiotic association when subcultured daily in milk for long periods of time.3. The phage ‘carrying’ power of the cultures was of a non-inherent nature. ‘Purification’ of the phage-carrying cultures by plating resulted in the production of phage-free colonies.4. Under certain circumstances, the presence of symbiotic phage in a culture gave a measure of protection against attack by other phage races.
The synergic action of penicillin and sulphathiazole onS. typhi
Authors: Thomas John C. , Hayes William 
Published: May 2009

Due to earlier reports of the relative resistance ofS. typhiand other members of the salmonella group to penicillin, and to the prevalent preoccupation of most workers with those organisms against which treatment with penicillin was more obviously applicable, little attention was payed to the chemotherapy of enteric fever until Bigger (1946) published his findings on the synergic action of a more reliable guide to the occurrence of synergism than sterilization, might be demonstrated. In conformity with the previous results, however, treated broth was also used to demonstrate synergic killing effect. Results are given in Table 12.T455, when tested under similar conditions, was inhibited by 6·25 u./ml. penicillin and showed a twofold inhibitory synergism in the presence of sulphathiazole. It will be seen that all the strains tested showed some degree of inhibitory synergism but that, in the majority, the concentration required to inhibit growth was considerably higher than in the case ofS. typhi. With the majority of strains the concentration of penicillin required to destroy the inoculum in 24 hr. at 37° C. was greater than 25 u./ml., even in the presence of sulphathiazole, while in one case no bactericidal synergism at all penicillin and sulphathiazole againstS. typhi. Although, therefore, much work has been published concerning the synergic action of the sulphonamide group on penicillin activity in general, little information is available on thein vitrobehaviour of the salmonellas in this respect despite the present wide, though tentative, application of the principle in the treatment of enteric fever. The experiments presented above were undertaken with the object of confirming those findings hitherto reported and of studying in detail the effects of sulphathiazole and penicillin, and of combinations of the two, on the salmonella group, with special reference toS. typhi.For purposes of discussion it is convenient to summarize our results under the principal headings used in the text.
The adjustment of biological assay results for variation in concomitant observations
Authors: Finney D. J. 
Published: May 2009

When individual responses in a biological assay show considerable variation associated with the values of a concomitant variate, covariance analysis may be used in order to adjust the mean responses and to improve the precision of the assay. Usually this is preferable to the choice of an adjustment which involves an arbitrary assumption about the effect of variations in the concomitant variate on the measured response. Published accounts of the process are open to certain theoretical objections, though they may be sufficiently exact for most practical purposes.The present paper describes a method of calculating the relative potency, and its precision, which may be a little more laborious, but which is in full accord with standard statistical practice. The computations are illustrated on data from a prolactin assay by the pigeon crop-gland technique, in which the final crop-gland weight showed a positive correlation with the body weight at the start of the assay. The results are compared with those obtained either from the unadjusted crop-gland weights or from these weights expressed as proportions of body weights. The covariance method leads to a more precise estimate of the potency of the test preparation than do either of the others; there is evidence, however, that the increase in precision will not necessarily be large unless the correlation between the response and the concomitant variate is very close.In a final section, the full statistical tests of assay validity in the covariance analysis are described; these are lengthy, and fortunately are required only when the validity is in considerable doubt.The methods of adjustment have been described in this paper with respect to an assay depending upon parallel regression lines of responses on the logarithms of doses. They may be adapted for use with ‘slope-ratio’ assays (Bliss, 1946; Finney, 1945; 1948; Wood & Finney, 1946), in which the regression of response on dose itself is linear. So far the need for adjusting for concomitant variation in these assays seems not to have arisen, and discussion of computational details may be postponed until the need is felt.
The conglutination phenomenon. II. The technique of the conglutinating complement absorption test compared with the haemolytic complement fixation test
Authors: Hole N. H. , Coombs R. R. A. 
Published: May 2009

1. A brief introduction has been given to the conglutination reaction.2. The technique used by us for carrying out the conglutinating complement absorption test has been described in detail and compared with that used for the haemolytic complement fixation test.
The bacteriological examination of molluscan shellfish
Authors: Clegg L. F. L. , Sherwood H. P. 
Published: May 2009

Section IA standard bacteriological test for molluscan shellfish should fulfil certain requirements stated: briefly, the test should show the degree of pollution, be accurate and rapid, and self-sufficient, not requiring subsequent confirmation. Review of the subject leads to recommendations, first, to overcome the technical difficulties of preparing samples for testing; secondly, on the nature of the test. In preparation: external shell sterilization can usually be omitted, shell water should be discarded and replaced by sterile water to make a total volume three times that of the body tissues. Pooling of individual shellfish into one sample is acceptable in routine examinations. In the test: a solid medium is preferable to a liquid medium, giving more accurate results, and review of existing tests leads to the conclusion that the use of roll tubes of MacConkey agar incubated at 44° should meet the requirements of a standard test.Section IIA modification was found necessary in the MacConkey agar: a mixture of 2 % gelatin and 5 % agar is used instead of the normal 2 % agar. Mechanical rolling devices for tubes are described and figured.Among other critical experiments, 1000 roll-tube colonies grown at 44° from shellfish included 969 with + + − − ‘IMViC’ reactions and 979 acid and gas producers at 44°. The coefficient of variation among replicate tests of samples of shellfish and water in roll tubes was not seriously greater than that for colony counts in Petri dishes at 37° with ordinary MacConkey agar.Colonies in roll tubes incubated at 44° can be counted as conveniently and accurately as those on Petri dishes, and, in general it is concluded that the new method is more satisfactory for estimation of faecalcolithan other methods at present in use.Section IIIDirections are given for the preparation of shellfish and inoculation into roll cultures, both for individual and for pooled examination, and the method of determining results is described.The interpretation of results is discussed, and it is suggested that shellfish which in four out of five samples from the same source are free from faecalcoliin 1 ml. quantities of body tissue should be regarded as satisfactory for food. The presence of more than two or three faecalcoliper ml. of body tissue in any one sample calls for appropriate action according to the number present.
The source of infection in Pemphigus neonatorum
Authors: Parker M. T. , Kennedy J. 
Published: May 2009

An outbreak of eighteen cases of pemphigus neonatorum in a maternity department is described.Strains ofStaph. aureusisolated from the infants, the mothers and the staff during several weeks of intensive investigations were classified by phage typing.The findings indicated that, during the latter part of the outbreak at least, the adults were not the source of infection.There was evidence of wide dissemination of the epidemic strain ofStaph. aureusamong the healthy infants in the nursery. It is suggested that the main path of infection was from infant to infant.Methods of controlling established outbreaks are discussed.