Inagglutinable strains of B. typhosus are of considerable interest bacteriologists both from a practical and theoretical aspect. These strains present the usual characteristics of the typhoid bacillus, with exception that they are not agglutinated by anti-typhoid sera, if and such a contingency be overlooked one may fail to recognise that one dealing with a typhoid infection. This feature persists in the subcultures for many months, thus differentiating the inagglutinable strains from the many strains of B. typhosus which agglutinate with difficulty when freshly isolated but which regain their full agglutinability after one or two subcultures. Since their discovery these inagglutinable strains have been investigated on several occasions without any definite agreement as to the condition being arrived at.

The final choice of a suitable dilution of a given toxin will be made, partly from the difficult comparison with other known toxins, but mainly from the results of clinical observations in patients in the early stage of scarlet fever and in convalescents.

It is difficult to titrate scarlet fever toxin with accuracy. It will probably be found that by careful choice of subject and by several readings of the reactions at different intervals after the injection, one can differentiate between toxins of values x and 2x.

The vaccination of sheep with one dose of the monkey-and mouse-attenuated tick-borne encephalitis virus (the Hy-HK 28 ‘2’ clone) causes seroconversion from negative into positive in 85% of animals. In sheep with pre-existing virus-neutralizing antibodies and increas of their titres was observed in 81%. The antibodies persisted for at least 12 months after the vaccination and during the summer period of grazing the number of serologically positive animals even increased.

The vaccinated animals, in contrast to the non-immune control sheep, developed no viraemia after challenge with the virulent louping-ill virus, performed 11 months after immunization.

Skin and soft tissue infection (SSTIs) due to Staphylococcus aureus, particularly community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), are common in human immunodeficiency virus (HIV)-infected populations in the United States. Studies have differed as to the importance of epidemiological and immunological factors in this relationship, and have employed conflicting strategies for variable selection in multivariate analyses. Developments in causal inference methods in epidemiology have emerged in the last decade to clarify relationships between variables and identify appropriate variables to include in and exclude from multivariate analysis. In this paper, we develop a causal diagram to clarify the pathways linking CA-MRSA and HIV. We focus on the role played by trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis, prescribed to many severely immunocompromised HIV patients and potentially protective against SSTIs, which both mediates and moderates the relationship between immunological parameters and SSTI risk. We demonstrate, using simulated data, that statistical models may yield biased results if they do not account for how HIV viral load may also be a marker of adherence to TMP-SMX prophylaxis. We conclude with a proposed causal model that includes both the epidemiological as well as immunological factors that may explain the increased risk of initial and recurrent SSTI risk in HIV-infected populations.

Seroprevalence estimation using cross-sectional serosurveys can be challenging due to inadequate or unknown biological cut-off limits of detection. In recent years, diagnostic assay cut-offs, fixed assay cut-offs and more flexible approaches as mixture modelling have been proposed to classify biological quantitative measurements into a positive or negative status. Our objective was to estimate the prevalence of anti-HCV antibodies among drug users (DU) in France in 2011 using a biological test performed on dried blood spots (DBS) collected during a cross-sectional serosurvey. However, in 2011, we did not have a cut-off value for DBS. We could not use the values for serum or plasma, knowing that the DBS value was not necessarily the same. Accordingly, we used a method which consisted of applying a two-component mixture model with age-dependent mixing proportions using penalised splines. The component densities were assumed to be log-normally distributed and were estimated in a Bayesian framework. Anti-HCV prevalence among DU was estimated at 43.3% in France and increased with age. Our method allowed us to provide estimates of age-dependent prevalence using DBS without having a specified biological cut-off value.

The want of success which has so persistently attended the efforts of most bacteriologists to isolate the B. typhosus from water supplies suspected to have caused enteric fever, suggested a study of the varieties of B. coli which are associated with the B. typhosus in the dejecta of patients suffering from enteric fever. It was hoped that the organisms in question might show cultural characteristics or reactions to specific sera, which would enable them to be distinguished from the varieties of B. coli present in the dejecta of healthy people; so that even if the B. typhosus were not detected, the presence of these special organisms might afford reasonable grounds for the belief that the water under examination had been fouled by the specific dejecta of cases of enteric fever. With this object in view 150 organisms have been examined; of these 80 were isolated from the stools of cases of enteric fever and 70 from the stools of healthy men. The enteric fever cases were five in number, one being a severe relapse, and the other four severe cases which terminated fatally. The stools were obtained during the third and fourth weeks of the disease and also, in the fatal cases, from the intestines after death had occurred.

The method most commonly employed for the separation of antitoxic globulins is that by means of Ammonium Sulphate, and this was the process used in these laboratories for several years until, at the end of 1917, the supply of the necessary salt was cut off. We were then thrown back on Sodium Sulphate, a salt we had used before the War but which had not given us satisfactory results. A few fresh trials, however, showed us the faults of our previous technique and proved that Na2SO4 could satisfactorily replace Am2SO4 and so, since February 1918, we have used only the former salt. Changes in detail have been made from time to time and we have now established a routine method which has for some time given us satisfactory results.

Hay Fever is a disease which on account of its peculiar interest has attracted the attention of the medical world ever since it was first accurately described by Bostock of London in 1819. To what extent the disease occurred before his time is difficult to determine; but from the fact that his observations were at once confirmed by a number of contemporary medical men it is probable that at the time of his writing it was not very uncommon. We have no exact knowledge of the existence of the disease in England prior to the nineteenth century, and indeed many authors hold that the chief etiological factors were not present in earlier times. It is my purpose in this paper to discuss the researches recently carried out by Prof. Dunbar at the State Institute of Public Health in Hamburg, which have very considerably increased our knowledge of the interesting malady, and have also narrowed the field for its future investigation.

1. The outbreak was one of bacterial food poisoning due to the consumption of infected milk.

2. The casual organism was B. enteritidis of Gaertner (Dublin).

3. A case of gastro-enteritis occured in an employee in the institution some days previously. This man's serum possessed agglutinins for for Gaertner'sbacillus, but the organism was not isolated from a specimen of his faeces taken 44 days after this attack.

4. This employee is supposed to have been the source of the organism which infected the milk. Two hypotheses are put forward to explain the mechanism of infection.

5. Servants who took the infected milk in their tea escaped infection. The milk was added to the tea in bulk and the experiments described satisfactoryily account for their escape.

The origin and object of the following paper can be explained in a few words. In April, 1904, the writer published a series of 280 blood examinations (to which were added about 150 more) of natives of southern Angola (Portuguese West Africa) without recording a single instance of the presence either of trypanosomes or of spirochaetes in the circulation. Quite recently in the course of an investigation of the endemic malaria of the same district, 513 examinations made among the same people and with the same technique revealed 3 individuals harbouring trypanosomes and 4 showing spirochaetes in their blood. These observations, together with the fact that a year or so ago the natives reported no cases of Tick Fever, while recently statements are made by them that the Tick Fever of the upper Zambezi has reached Angola, and also the fact that Sleeping Sickness is reported to be advancing southward through the province, have led me strongly to suspect that these diseases have lately begun to spread markedly in my part of the colony, and that one or both of them may not inconceivably assume in the near future epidemic proportions.

It is usually accepted that in precipitin reactions a definite quantity of precipitin interacts with a definite quantity of homologous proteid, and further that in ordinary circumstances the interacting quantities combine to give rise to a precipitate, the precipitum. From this it follows that, if a known weight of serum containing precipitin be allowed to react with various weights of homologous proteid and if the quantities of proteid be sufficiently varied, certain reactions will be completed and others will be incomplete. The addition of precipitin and of homologous proteid to the superfluid of each reaction will determine the presence of excess of precipitin or of homologous proteid in such fluid. Conversely, if a known weight of the homologous proteid be allowed to interact with various weights of serum containing precipitin, it will be possible to determine in a similar manner those reactions which have been completed and those in which the homologous proteid or the precipitin is in excess. If the first stated proposition be correct, the results of these two series should coincide. A definite weight of serum containing precipitin should interact with a definite weight of proteid to from the precipitum.

In his classical treatise on Contagions, Hieronymus Fracastorious of Verona has the following passage: “I recollect a singular contagion of the year 1514 which affected only oxen; it first showed itself in the district of Frioli, then gradually extended to northern Italy and thence reached our country. At first the ox went off its feed without any obvious cause, but if the herdsmen looked into the mouth a certain roughness and small pustules were noted on the palate and the whole oral cavity. It was necessary at once to isolate the infected beast from the rest of the herd, otherwise all became affected. Gradually the disease descended to the shoulders and thence to the feet, and almost all the beasts in which this happened recovered, but when it did not, they usually died” (Fracastorii, pp. 63–4). Probably, as in the parallel case of influenza, a careful search of earlier literature might show that foot-and-mouth disease had played its part before 1514. It is sufficient for my present purpose to establish that it has been recognised, very much in its actual clinical form for more than 400 years.

Two elementary schools were served lunches that were cooked in the same kitchen. An outbreak of Escherichia coli O157:H7 occurred at one school where the dishes that were prepared for the school were lukewarm and kept for 33 min at an average temperature of 45 °C before serving. However, no outbreak occurred at the other school where dishes were hot and were kept for 60 min at an average temperature of 50 °C before serving. In a series of experiments on the survival of E. coli O157:H7 in the liquid portion of similarly prepared food, the population of E. coli O157:H7 was reduced by 10−3 by heating at 50 °C for 60 min and by only 10−1 by heating at 45 °C for 40 min. Further, E. coli O157:H7 survived at 45 °C for 40 min but not at 50 °C for 60 min at pH 4·0 with a 4·0% salt concentration that was similar to that of the liquid part of the food. These results indicate that pH and salt concentration of cooked food markedly affect the survival of E. coli O157:H7 and help to explain the occurrence of the disease outbreak at only one of the schools.

This study assessed accuracy of (a) recording Vibrio vulnificus infection on death certificates and (b) International Classification of Disease (ICD)-9 codes for V. vulnificus. Patients with microbiologically confirmed V. vulnificus infection were identified as part of co-ordinated surveillance in four USA Gulf Coast states between 1989 and 1993. Of 60 deaths, 51 death certificates were reviewed and V. vulnificus was recorded as the immediate cause of death on 11 (22%). There was no ICD-9 code for V. vulnificus infection, thus no patients had an ICD-9 code indicating V. vulnificus infection. Of 23 certificates where V. vulnificus was recorded on the death certificate, only 5 (22%) were coded for Gram-negative, septicaemia. This study highlights the importance of teaching physicians how to provide epidemiologically meaningful data on death certificates and the need for accurate ICD mortality codes.

Rates of acquisition and loss of Brugia malayi microfilaraemia were estimated using the parasitological data of a cohort of population in Shertallai, South India. The rate of acquisition of microfilaraemia was found to be dependent on age but not gender. The decline in the rate of acquisition of microfilaraemia in adults above 35 years could be due to the development of acquired immunity. The mean reproductive lifespan for the periodic Brugia malayi adult female worm was estimated to be 34 years and it was independent of host age and gender. The age-specific estimated proportion of population at risk (microfilaria carriers who lost their microfilaria in course of time) of developing lymphoedema approximately mirrored the observed age specific prevalence of lymphoedema in the study-population. On an average, 99% of population at risk developed manifestations of disease. The estimated population at risk of developing disease in different endemic areas is compared and its epidemiological significance is discussed.

Among the formulae which describe relationships found in physics, chemistry and biology is one commonly known as the “adsorption formula.” It graduates for a considerable range of experiment the amount of adsorption which takes place at the bounding layers of solids, fluids and gases or immiscible fluids in presence of different concentrations of the substance adsorbed. It may be written in the form x = aCn where x is the amount of the substance adsorbed; C the concentration of the adsorbed substance after equilibrium has been attained; n is an absolute constant less than unity; and a is a constant depending in value on the units of measurement.

In many hospital wards it is usual to have a certain proportion of the beds separately accommodated in single-bed rooms. Current practice shows a great variety not only in the availability of separate accommodation but also in the use made of such a facility. A clear understanding of both the demand and the way in which it can be met is of great importance in the theory and practice of ward design. This problem has been discussed in a recent paper by J. W. D. Goodall (1951), who, using purely medical criteria for the need for separate accommodation, considered that present practice was on the whole largely inadequate. He found it convenient to divide patients into two groups. First, those who have to be kept under close observation, such as dying cases, infants under 2 years, cases of posttraumatic psychosis, patients requiring special treatment, and so on. These are called type A patients, and their beds must be situated for easy observation and attention. Secondly, there are those who need to be separated but who do not require constant nursing supervision, such as patients who are liable to infect others or who are peculiarly susceptible to infection, burns cases and physically unpleasant patients, etc. These are of type B and need not be placed in such immediately accessible parts of the ward. Goodall obtained data from many different hospital wards showing the day-to-day demand for single rooms over, in most cases, at least a month.

1. Naturally occurring agglutinins to paracolon bacilli have been found in seven out of ten sera from non-immunized rabbits and in one anti-Salmonella and two anti-paracolon immune rabbits' sera after complete absorption with the immunizing strain.

2. The a antigen of Stamp & Stone, which is known to occur as a natural agglutinin, has been demonstrated in one out of nine paracolon bacilli.

3. Rabbits which before immunization show agglutinins to the immunizing strain or to an α antigen should not be used for the preparation of diagnostic antisera for intestinal Gram-negative bacilli.