In laboratory experiments the acute eye irritation produced by exposure to tap water was not significantly increased when chlorine compounds were added to the water at concentrations of 1 mg./l. The greatest irritation was produced by 2 mg. Cl2/1. as NH2C1. The addition of NaCl at concentrations above about 0·5% abolished the irritant effect of tap water, and prevented irritation even when 1 mg. Cl2/1. was present.

In a field experiment involving two swimming baths, one with fresh and the other with saline water (0·5 % NaCl), eye irritation in the saline bath was significantly lower than in the freshwater bath only when the swimming time did not exceed 30 min.

1. A given strain of Bact. aertrycke was sub-cultured daily, except on Sundays, in 5–7 c.c. of casein broth, pH 7·4–7·6, under different partial pressures of oxygen. Most experiments were continued till about ninety sub cultures had been made. Virulence determinations were made from time to time by intraperitoneal inoculation of twenty mice with about 100 living organisms, the control and the experimental cultures generally being tested simultaneously. The results showed that under anaerobic conditions there was no appreciable change in virulence. Under the usual aerobic conditions, and in partial pressures of oxygen varying from 1 to 21 per cent., the virulence declined, the extent and rapidity of the fall increasing with the pressure of oxygen supplied. In high partial pressures of oxygen, varying from 40 to 100 per cent., there was a slight increase in virulence, the increase being greatest in cultures incubated in pure oxygen.

2. Some of the literature dealing with incitants to microbic dissociation is discussed, particularly that dealing with variations in oxygen pressure.

3. In explanation of the experimental results obtained, a tentative hypothesis is put forward with reference to the dissociation of Bact. aertrycke. It is suggested that under aerobic conditions, and under low partial pressures of oxygen generally, substances are formed in the medium, as the result of growth, which favour dissociation, and lead to the appearance of weakly virulent or completely avirulent variants. Under anaerobic conditions these substances either are not formed at all, or appear in amounts too small to be of significance. In cultures incubated in high partial pressures of oxygen, these substances are formed, probably in large quantity, but owing to the high alkalinity of the medium and the abundant oxygen present, they undergo rapid destruction. This explanation is based on the fact that many protein degradation products, particularly those with a phenolic grouping, prove markedly unstable in an alkaline medium in the presence of free oxygen.

As an alternative hypothesis it is suggested that the maintenance of the organisms in the virulent state depends on the intracellular pH. Under anaerobic conditions it is supposed that the metabolism is such as to lead to no marked change in the H-ion concentration within the cell. In the presence of air and of low pressures of oxygen generally, owing to the breakdown of the protein in the medium and the production of ammonia, the intracellular reaction becomes more alkaline; whereas in high pressures of oxygen the increased amount of CO2 produced is sufficient to compensate for the production of ammonia, and the intracellular pH remains more or less at its original value. This hypothesis rests on the observation of Stephenson and Whetham (1924) that in high pressures of oxygen Bact. coli may produce considerably larger quantities of CO2 from lactic acid than under ordinary aerobic conditions; and on the demonstration by Jacobs (1920 b) that, owing to the ease with which CO2 is able to penetrate the living cell, the intracellular pH may differ markedly from that of the medium to which the cell is exposed.

4. It is of interest to note that Bact. aertrycke, when incubated under partial pressures of 40 to 75 per cent. of oxygen, rapidly passed into the nonmotile O form.

We investigated risk factors associated with COVID-19 by conducting a retrospective, frequency-matched case-control study, with three sampling periods (August–October 2020). We compared cases completing routine contact tracing to asymptomatic population controls. Multivariable analyses estimated adjusted odds ratios (aORs) for non-household community settings. Meta-analyses using random effects provided pooled odds ratios (pORs). Working in healthcare (pOR 2.87; aORs 2.72, 2.81, 3.08, for study periods 1–3 respectively), social care (pOR 4.15; aORs 2.46, 5.06, 5.41, for study periods 1–3 respectively) or hospitality (pOR 2.36; aORs 2.01, 2.54, 2.63, for study periods 1–3 respectively) were associated with increased odds of being a COVID-19 case. Additionally, working in bars, pubs and restaurants, warehouse settings, construction, educational settings were significantly associated. While definitively determining where transmission occurs is impossible, we provide evidence that in certain sectors, the impact of mitigation measures may only be partial and reinforcement of measures should be considered in these settings.

In the Berkefeld filtration of a fresh guinea-pig serum, adsorption on the filter surface takes place, and the serum passes unaltered, if the saturation of the adsorbing surface has become complete.

This adsorption involves most probably first the albumins, which process then secondly influences the filtrability of the globulins. It is also shown that the physical conditions of the serum as regards salt concentration and dilution as well as H.-concentration modify the effect of filtration to a large extent.

Burn patients are at high risk of central line–associated bloodstream infection (CLABSI). However, the diagnosis of such infections is complex, resource-intensive, and often delayed. This study aimed to investigate the epidemiology of CLABSI and develop a prediction model for the infection in burn patients. The study analysed the infection profiles, clinical epidemiology, and central venous catheter (CVC) management of patients in a large burn centre in China from January 2018 to December 2021. In total, 222 burn patients with a cumulative 630 CVCs and 5,431 line-days were included. The CLABSI rate was 23.02 CVCs per 1000 line-days. The three most common bacterial species were Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa; 76.09% of isolates were multidrug resistant. Compared with a non-CLABSI cohort, CLABSI patients were significantly older, with more severe burns, more CVC insertion times, and longer total line-days, as well as higher mortality. Regression analysis found longer line-days, more catheterisation times, and higher burn wounds index to be independent risk factors for CLABSI. A novel nomogram based on three risk factors was constructed with an area under the receiver operating characteristic curve (AUROC) value of 0.84 (95% CI: 0.782–0.898) with a mean absolute error of calibration curve of 0.023. The nomogram showed excellent predictive ability and clinical applicability, and provided a simple, practical, and quantitative strategy to predict CLABSI in burn patients.

The outbreak of cattle plague in Egypt and the establishment of the Serum Institute at Abbassieh offered a suitable opportunity for investigating some points concerning the nature of the causal agent of the disease, and especially the important question whether the virus is, or is not, capable of traversing a filter candle. On this point the literature is strangely contradictory.

A new salmonella subgenus I serotype is described. Strain C.S. 1608/73, serotype 67: r: 1, 2, was isolated from activated sewage sludge and was assigned the name S. crossness. The serotype is biochemically atypical in its ability to utilize sucrose and this ability appears to be controlled by a transferable plasmid.

Seven smallpox vaccines of known human pathogenicity were tested for their ability to produce pocks on the chick chorioallantois at 39·7° C. Significant differences were found and the more pathogenic strains produced pocks with greater efficiency at 39·7° C. than did strains of average or low pathogenicity.

In an uncompleted study in 1965 microscopic haematuria in the second or third week after acute pharyngitis was found four times more often in patients with either microbiological or clinical evidence of dual infection with both group A streptococci and a virus than in patients with evidence only of infection with group A streptococci.

Prospective studies of the role of viruses in the aetiology of transient haematuria and of acute post streptococcal glomerulonephritis are feasible in general practice and would be most productive if concentrated in children 5–9 years of age.

SARS-CoV-2 serological tests are used to assess the infection seroprevalence within a population. This study aims at assessing potential biases in estimating infection prevalence amongst healthcare workers (HCWs) when different diagnostic criteria are considered. A multi-site cross-sectional study was carried out in April–September 2020 amongst 1.367 Italian HCWs. SARS-CoV-2 prevalence was assessed using three diagnostic criteria: RT-PCR on nasopharyngeal swab, point-of-care fingerprick serological test (POCT) result and COVID-19 clinical pathognomonic presentation. A logistic regression model was used to estimate the probability of POCT-positive result in relation to the time since infection (RT-PCR positivity). Among 1.367 HCWs, 69.2% were working in COVID-19 units. Statistically significant differences in age, role and gender were observed between COVID-19/non-COVID-19 units. Prevalence of SARS-CoV-2 infection varied according to the criterion considered: 6.7% for POCT, 8.1% for RT-PCR, 10.0% for either POCT or RT-PCR, 9.6% for infection pathognomonic clinical presentation and 17.6% when at least one of the previous criteria was present. The probability of POCT-positive result decreased by 1.1% every 10 days from the infection. This study highlights potential biases in estimating SARS-CoV-2 point-prevalence data according to the criteria used. Although informative on infection susceptibility and herd immunity level, POCT serological tests are not the best predictors of previous COVID-19 infections for public health monitoring programmes.

We conducted a prospective cohort study between 1 January 2010 and 31 December 2012 at five adult and paediatric academic medical centres to identify factors associated with persistent methicillin-resistant Staphylococcus aureus (MRSA) colonisation. Adults and children presenting to ambulatory settings with a MRSA skin and soft tissue infection (i.e. index cases), along with household members, performed self-sampling for MRSA colonisation every 2 weeks for 6 months. Clearance of colonisation was defined as two consecutive negative sampling periods. Subjects without clearance by the end of the study were considered persistently colonised and compared with those who cleared colonisation. Of 243 index cases, 48 (19·8%) had persistent colonisation and 110 (45·3%) cleared colonisation without recurrence. Persistent colonisation was associated with white race (odds ratio (OR), 4·90; 95% confidence interval (CI), 1·38–17·40), prior MRSA infection (OR 3·59; 95% CI 1·05–12·35), colonisation of multiple sites (OR 32·7; 95% CI 6·7–159·3). Conversely, subjects with persistent colonisation were less likely to have been treated with clindamycin (OR 0·28; 95% CI 0·08–0·99). Colonisation at multiple sites is a risk factor for persistent colonisation and may require more targeted decolonisation efforts. The specific effect of clindamycin on MRSA colonisation needs to be elucidated.

Two outbreaks of salmonella food poisoning are described. In one, involving 55 persons, the infecting organism was Salmonella reading, and in the other, involving 39 persons, S. tennessee. In both, epidemiological and bacteriological evidence pointed to imported cans of cooked meat as the source. The role of contaminated shop equipment in furthering the spread of infection is particularly emphasized.

Attention is drawn to the severity of the symptoms and prolonged excretion of the organism in a number of the patients infected with S. reading.

Vaccination is a significant preventive measure to contain the coronavirus disease-2019 (COVID-19) pandemic. Vaccination rates can provide useful information on the potential spread of infection in a given population. In this study, vaccination rates and attitudes towards vaccination in cultural sectors, specifically the music sector, have been investigated. In total, 4341 persons in four different areas, including visitors to performances of classical music and musicals, as well as professional and amateur musicians, have participated in this survey. Results show rates of 86% recovered from the COVID-19 virus or vaccinated at least once, with 54.5% fully vaccinated. These vaccination rates were considerably higher compared to the general population. An attitude of hesitation towards vaccination found in 6.4% of those sampled was half that of the general population. These findings drawn from a large sample indicate that in the field of music a high vaccination rate is to be found, as well as a low rejection rate of vaccination on the part of the audience and performers. The results can be used to provide insights into the vaccination status to be found at cultural events and, importantly, to assist in consideration of whether cultural events should be permitted to continue under pandemic circumstances.

A heterogeneous sample consisting of eighteen specimens of semen provided by eleven patients was examined. Smears were supravitally stained at 3, 8 and 27 hr. Counts of living and dead spermatozoa, classified into normal and fourteen types of abnormal forms, showed that whereas five abnormal forms were always dead, the remaining types showed varying proportions of dead and living cells. Their rate of mortality was somewhat greater than that of normal spermatozoa.

(1) The graphic method is more easy of application and requires less mathematical knowledge than the extended analytical method.

(2) In our experience it produces smooth curves of px and Ex.

(3) The analytical in the selection of the best process of interpolation appeals to the graphic method.

(4) While either the analytical or graphic process may in unskilful or careless hands give erroneous results, owing to errors in working out, the analytical process, unlike the graphic, presents a wide choice of methods, which although accurately worked out, give incomparable results.

(5) The facts given in the table on page 321 and in Fig. 1 A and B and table on page 317 show that almost identical results are obtained by the graphic method and by the improved extended analytical method. We regard this as important testimony to the accuracy of each of these methods, and at the same time as indicating the inaccuracy of the analytical methods giving different results.

(6) As the results obtained by the modified short analytical method and by the combined analytical and graphic method approximate so closely to those obtained by the detailed graphic method, either of them may safely be adopted by those who cannot spare time for working out a detailed Life Table by the graphic method.

(7) Every published Life Table should give exact details of the method of its construction, in order that the comparability of data and results may be tested. Much confusion has arisen, and important errors in comparison between different Life Tables have been produced, by the use of different methods of construction and the non-publication of details of methods.

Varicella is a highly infectious contagious disease, and Chongqing is one of the high incidence areas in China. To understand the epidemic regularity and predict the epidemic trend of varicella is of great significance to the risk analysis and health resource allocation in the health sector. First, we used the ‘STL’ function to decompose the incidence of varicella to understand its trend and seasonality. Second, we established SARIMA model for linear fitting, and then took the residual of the SARIMA model as the sample to fit the LS-SVM model, to explain the non-linearity of the residuals. The monthly varicella incidence peaks in April to June and October to December. Mixed model was compared to SARIMA model, the prediction error of the hybrid model was smaller, and the RMSE and MAPE values of the hybrid model were 0.7525 and 0.0647, respectively, the mixed model had a better prediction effect. Based on the study, the incidence of varicella in Chongqing has an obvious seasonal trend, and a hybrid model can also predict the incidence of varicella well. Thus, hybrid model analysis is a feasible and simple method to predict varicella in Chongqing.

The acute rodenticide gophacide was tested against urban infestations of the house mouse (Mus musculus L.) and treatment success was assessed from the results of census baitings conducted before and after each treatment. Seven of eight populations of mice living in premises where alternative food supplies were limited were successfully controlled when medium oatmeal bait containing gophacide at 0.1% was laid directly for 4 days. In further treatments against mice inhabiting more complex environments and having greater access to other foods, the performance of gophacide at 0.1% and at 0.25% in a wholemeal flour/pinhead oatmeal/corn oil bait was compared with that of zinc phosphide at 3.0% in the same bait-base. The poison treatments were conducted for 1 or 4 days and always after 3 days pre-baiting. Treatment success varied considerably irrespective of the type of treatment or of the poison used. In general, however, gophacide proved to be as effective as zinc phosphide for the control of mice.

In order to study the serological status of the Northern Greek population to poliovirus, 881 sera from healthy people were examined for neutralizing antibody by the micrometabolic inhibition test. The people under examination were aged from 1 day to 70 years old. Overall, of the 881 sera examined, 704 (80%) had antibodies (titre ≥ 4) to poliovirus 1, 742 (84%) had antibodies to poliovirus 2 and 715 (81%) had antibodies to poliovirus 3. Fifty-five per cent of the sera had antibodies to all three polioviruses while 3·3% had no poliovirus antibody at all. There was no statistically significant difference in the rates of seropositivity to the various poliovirus types or between males and females. However the rates of seropositivity did vary with age.

Fluorescein dispersed as powder into the air of occupied rooms was extracted in measurable quantities from dust after as many as twenty previous sweepings.

The value of fluorescein in showing the rate of removal of dust from occupied environments is discussed in relation to the transfer of infection.

1. Of five experimental subjects—growing East African native boys—four proved to have definitely negative calcium balances on the diet in use at the Nairobi Prison, while the fifth was merely in calcium equilibrium.

2. The diet in question was found to be so low in calcium (0·32 grm. Ca per day) that the occurrence of negative balances is not altogether surprising.

3. These negative calcium balances became positive on the addition of calcium as milk or in a mineral mixture with or without cod-liver oil.

4. Cod-liver oil alone was not effective in bringing about any appreciable reduction of a negative balance.

5. Our findings showed that 0·43 grm. Ca daily was the maintenance requirement for the subjects under experiment. This figure is practically the same as that found by Sherman in a summary of work on white races.

6. On giving additional calcium in a mineral mixture it was found that after the maintenance requirement had been satisfied, as much as 50 per cent. of any excess might be retained. The calcium of milk, on the other hand, was found to be utilised more efficiently; the corresponding retention figure being over 70 per cent.

7. The influence of the various supplements on growth is briefly discussed.