1. An M-producing strain of Streptococcus pyogenes type-12 was shown to be carried on the surface of apparently healthy tonsils for at least 3 years.

2. Loss of M substance in a strain of type-3 in a tonsillar carrier was shown to be by gradual replacement of matt forms by glossy variants. This pair of naturally occurring variants showed very different growth rates as mixtures in liquid media.

3. Under suitable conditions, glossy variants regularly appeared and replaced the M-producing strain from which they were derived in these and all other strains of type-3 and type-12 tested from a wide variety of sources.

4. It is suggested that the selection of variants by the differential nutrient value of the micro-environment is the deciding factor in carrier strains showing loss of M substance.

In our previous paper in this Journal it was shown that the temperature of 46°C.1 recommended by Eijkman and Bulir in their fermentation test is excessively high, as in water cultures it has a destructive effect on Bact. coli. This was in accordance with the previous work of Brown and Skinner (1930) and Skinner and Brown (1934). At the same time we were able to show that in cultures in Bulir's medium at 43° not only is the destructive effect of the excessively high temperature on Bact. coli removed but the reproduction and fermentation activity of this organism is distinctly stimulated. At 43° Eijkman's and Bulir's tests effectively distinguish between true Bact. coli communis and other strains.

The subject I propose to discuss in the present and subsequent papers is of importance in two ways. Popular traditions have frequently implied that the age at which a parent begets offspring is not without influence upon the characters of the latter, the prevailing belief being humorously portrayed in the late W. S. Gilbert's ballad “The Precocious Baby.” Again, recent thinkers, notably Professor Karl Pearson, have asserted that elder born children differ markedly in liability to certain diseases from their younger brethren. Were this view to be accepted it would be relevant to enquire whether the difference might not be a function of the age of the parents at the time of birth of the offspring or at least whether such difference might not play a part in bringing about this result. Assuming that any such effect could be demonstrated, it is plain that a valuable stimulus would be given to the study of physiological changes in the reproductive system within the fertile period. These are the immediately interesting aspects of the subject, but with them I am less directly concerned than withcertain secondary consequences.

Only studies in the UK on individuals dying from coronavirus disease 2019 (COVID-19) in hospital have been published, to date. Cremation law requires collection of clinical information that can improve understanding of deaths in both hospital and community settings. Age, sex, date and place of death, occupation, comorbidities and where infection acquired was recorded for all deaths from COVID-19, between 6 April and 30 May, for whom an application was made for cremation at a South Wales' crematorium. Of 752 cremations, 215 (28.6%) were COVID-19 (115 (53.5%) male and 100 (46.5%) female). Median age was 82 years (youngest patient 47 and the oldest 103 years). Over half the deaths (121/215: 56.3%) were over 80 years. Males' odds of dying in hospital, rather than the community were 1.96 times that of females (95% confidence intervals (CI) 1.03–3.74, P = 0.054) despite being of similar age and having a similar number of comorbidities. Only 21 (9.8%) of 215 patients had no comorbidities recorded. Patients dying in care homes were significantly older than those dying in hospital (median 88 years (interquartile (IQ) range 82–93 years) vs. 80 years (IQ range 71–87 years): P < 0.0001). Patients dying in hospital had significantly more comorbidities than those dying in care homes (median 2: IQ range 1–3 vs. 1: IQ range 1–2: P < 0.001). Sixty three (29.3%) of infections were hospital acquired and a further 55 (25.6%) acquired in care homes. In a series, of hospital and community deaths, persons over 80 with an average two comorbidities predominated. Men were more likely to die in hospital. Half the infections were acquired in hospitals or care homes with implications for management of the pandemic.

The twenty-four young women and one man treated in an ultra-clean isolation ward should have had a low incidence of staphylococcal infection on grounds of age, sex and clean environment alone. However, they apparently acquired new strains of Staph. aureus at the rate of 4·7/100 patient weeks (3·9 multiple resistant strains/100 patient weeks) from the sixth week after admission onwards.

Environmental factors contributing to infection included introduction of resistant strains by the patients on admission, contact between patients in the unit, and failure to eliminate nasal carriage in staff and patients.

Host susceptibility was increased by malignancy, and by antibiotic and cytotoxic therapy. The nasal carriage rate of Staph. aureus was significantly greater for patients with repeated episodes of leucopenia induced by cytotoxic drugs.

The skins of grains, all flours and all bread contain bacteria belonging to the group B. mesentericus. The cultural characters of six types of B. mesenteriucus isolated from grains and flour are given. Five of these were also obtained from ropy (or sour) bread. None of these five types can be identified as corresponding to the organisms isolated by earlier workers on rope. Rope, or sourness, does not result from the presence of these bacteria unless conditions are such as to allow of great development. The factors determining development of rope in bread are (1) degree of infection, (2) moisture, (3) temperature, ? (4) reaction, and (5) composition of the flour. A method of estimating the degree of infection of flours is given.

1. It has been found possible to detect traces of the virus of foot-and-mouth disease in mixtures of this virus and that of vesicular stomatitis by cross-immunity tests in cattle. A quantity of the virus of foot-and-mouth disease as small as 1·3 I.D. 50 was revealed by the inoculation of such mixtures into cattle immune to vesicular stomatitis.

2. It is suggested that such a method would be useful in the analysis of possible mixed infections in field outbreaks.

3. The usefulness of complement-fixation tests to confirm the resolution of mixtures has been demonstrated.

The author wishes to thank the Director of this Institute, Dr I. A. Galloway, for his advice and encouragement. The technical assistance of Messrs E. Scoates and P. M. Mitchell is also gratefully acknowledged.

A case recently tried before Mr Justice Warrington (The Flour Oxidising Co., Ld. v. J. and R. Hutchinson) has brought to light, what I do not imagine is a matter of common knowledge, namely that large quantities of flour both in this country and abroad are artificially bleached in order it would appear primarily to satisfy the fancy of the public for white bread. The popular taste for the appearance of their food naturally leads the caterers to satisfy it; the yellowness of milk and its richness are usually associated together in the mind of the man in the street consequently it is very difficult now-a-days to purchase milk which has not been artificially coloured.

Antistreptolysin O titres in the sera of children in a rural population of Ceylon were determined, to establish the upper limit of the normal ASO titres in nonrheumatic children, and to compare these ASO titres with results of surveys done in other countries.

Swabs were taken from throats and ulcers of the children examined and cultured specifically for group A haemolytic streptoccoci. Of a total of 257 children, 29·5 % had ASO titres of over 166 Todd units. The greatest number of children showed ASO values between 100 and 166 units. The percentage of children showing values over 166 units increased with age until a maximum of 54 % was reached between 9 and 10 years. Group A haemolytic streptococci were isolated from five throat swabs, but there were no isolations from ulcers. The values obtained from this survey have been compared with those from a few other developing countries.

Nosocomial infection in intensive care unit (ICU) practice is a common problem and is associated with abnormal carriage of Gram-negative aerobic bacilli in the gastrointestinal tract, resulting in endogenous infections. Selective decontamination of the digestive tract (SDD) is a regimen aimed at preventing or eradicating this abnormal carriage.

A large number of trials examining SDD in ICU practice have been published, the vast majority showing a significant reduction in the incidence of nosocomial, Gram-negative infection. However, the impact on morbidity and mortality is much less certain. A recent meta-analysis has suggested a 10–20% reduction in mortality (3–6% absolute difference) with SDD. A discussion of these results is presented together with potential criticisms of SDD.

Since the emergence of Middle East respiratory syndrome coronavirus (MERS-CoV), Singapore has enhanced its national surveillance system to detect the potential importation of this novel pathogen. Using the guidelines from the Singapore Ministry of Health, a suspect case was defined as a person with clinical signs and symptoms suggestive of pneumonia or severe respiratory infection with breathlessness, and with an epidemiological link to countries where MERS-CoV cases had been reported within the preceding 14 days. This report describes a retrospective review of 851 suspected MERS-CoV cases assessed at the adult tertiary-care hospital in Singapore between September 2012 and December 2015. In total, 262 patients (31%) were hospitalized. All had MERS-CoV infection ruled out by RT–PCR or clinical assessment. Two hundred and thirty (88%) of the hospitalized patients were also investigated for influenza virus by RT–PCR. Of these, 62 (27%) tested positive for seasonal influenza. None of the patients with positive influenza results had been vaccinated in the year prior to hospital admission. Ninety-three (36%) out of the 262 hospitalized patients had clinical and/or radiological evidence of pneumonia. This study demonstrates the potential benefits of pre-travel vaccination against influenza and pneumococcal disease.

Water samples from home filters in nine residential areas of a Nigerian university community were studied. The membrane filter technique was used to determine the total coliform and faecal coliform counts/100 ml of water. Most of the 100 samples studied were grossly contaminated with total coliform counts/100 ml ranging from 0–442, faecal coliform counts/100 ml, 0–216 and the total aerobic plate count per millilitre ranged from 3·0 × 103 to 1·9 × 109 c.f.u. The source (dams) of water, fitness of filter candles, frequency of cleaning candles and pH of water did not significantly (P > 0·05; X2) affect the microbial quality of either filtered boiled or unboiled tap water.

Escherichia coli type I was isolated from 17·9% of the faccal coliforms tested but from only 2·3% of total coliforms. Enterobacter aerogenes was most predominant (38·5%) amongst faecal coliforms isolated while Enterobacter cloacae was the most frequent (37·2%) of the total coliform isolates.

The gross contamination of filltered water from all households sampled calls fpr am englightenment of residents on the proper use of home water filters.

The preparation of a medium that would allow the bacillus of diphtheria to grow and exclude all other organisms would be an ideal medium for those whose work is concerned with that organism, but, as such a medium has not yet been devised, we must be content with the modifications of the ordinary media which we possess. Various varieties of media have been prepared for the purpose of favouring the growth of B. diphtheriae, but very little seems to have been done with regard to selective media.

Neisseria cuniculi was isolated, between March 1987 and March 1989, from 38 cases of respiratory disease in small and large ruminants. In all but five cases N. cuniculi was cultured together with other potential respiratory pathogens. A survey was conducted to assess the prevalence of N. cuniculi in the pharyngeal region of Merino and Awassi purebred sheep, Awassi/East-Friesian and Merino/Romanov crossbred sheep and one exotic cross breed (goat/ibex).

N. cuniculi was isolated from 80–88% of the animals under 1 month of age. Among older animals, the microorganism was isolated from 20·5% of the pure bred animals and 79·3% of the crossbred ones. This difference was significant (P < 0·001) by the χ2 test. The prevalence of N. cuniculi in the second age group coincides with the susceptibility of the breeds to respiratory pathology.

This, we believe, is the first report of N. cuniculi involved in multiple cases of respiratory pathology and of a survey assessing the prevalence of this microorganism in small ruminants.

The antigenic response of guinea-pigs to live poliomyelitis viruses of all three types has been studied and the loss of antigenicity involved in inactivation by formaldehyde and by ultra-violet light have been determined.

We wish to acknowledge the debt we owe to the late Prof. M. van den Ende for his great help and interest in this work, and we are grateful for the assistance received from Dr H. Malherbe and Ruth Harwin in carrying out many of the titrations, and from Dr T. Mead for synthesizing some 1:4-diphenylbutadiene for use as a filter for ultra-violet light.

We also have to thank G. S. Turner, T. Norcott, Doreen Deeks and Margaret Pakes for their technical help.

The results of experiments designed to determine the threshold values for various thermal stimuli have been reported. The threshold increments in the intensity of radiation in ‘still’ air were determined first for several areas of exposure. In further experiments the effects of simultaneous changes in both the speed and temperature of the air, and the air speed and radiation intensity, were examined.

The data from these experiments were then used to estimate the relation between the temperature and speed of the air on the rate of heat loss by convection. The findings were shown to be in good accord with previously published data.

A clinical trial to determine the effect of oral Humatin therapy on the course of the chronic enteric carrier state in a group of twenty-seven typhoid and paratyphoid B carriers is described. It is concluded that the drug when administered orally in this group of carriers fails in the dosage given to effect a cure of the carrier state.

The microporous polyethylene hollow fibre membrane is capable of adsorbing small-sized lipopolysaccharides (LPS) prepared by sonication dispersion, column chromatography on Sephadex G-75 and filtration through a filter membrane with a nominal pore size of 0·025 μg. Small-sized LPS had a one-thousandth of endotoxin activity as compared to intact LPS, when determined by the Synthetic Chromogenic Substrate method of LAL with a specific endotoxin activity of 73·7 ng/μg LPS. Fluorescent microscopy of fluorescein conjugated LPS on a microporous polyethylene hollow fibre showed that fiuorescein-LPS was adsorbed through the entire depth of the membrane texture. Accordingly the adsorption capacity of the filter for small-sized LPS was determined as 1·65 mg LPS/3·68 m2 surface/116 mg fibre/module.

The mean isolation rates of salmonellas from the mesenteric lymph nodes and faeces of healthy mink were 16·7% of 618 animals from three farms and 3·9% of 772 animals from four farms respectively. Salmonella senftenberg was the most commonly isolated serotype. S. typhimurium, S. dublin, S. livingstone, S. menston, S. enteritidis, S. bredeney and S. infantis were also seen.

The prevalence of salmonellosis in 316 dead mink from 12 farms was 0·6%.

The epidemiological aspects are discussed.