Thermal comfort sensations are often studied in isolation, with the subjects' attention specifically directed towards their evaluation, both by instructions and by the recurrent act of questioning. A closer approach to the field situation, in which room temperature is at most a background stimulus, is made possible by the method of spontaneous magnitude estimation of thermal sensation. Thirty-six male and 36 female 17-year-old subjects in standard cotton uniforms (0·7 clo) were exposed in groups of 4 in a climate chamber to patterns of changing air temperature typical of conditions in occupied classrooms. Temperatures remained within the range 20–29° C. and did not increase more rapidly than 4° C./hr. Each individual recorded his thermal sensation on a dial voting apparatus, registering changes spontaneously as a secondary task while performing mental work during three successive 50 min. periods, with 10 min. breaks between. It was thus possible to obtain a measure of the time course of thermal discomfort sensations, including the extent to which they distracted attention. Significant differences were found between the responses of males and females, males in general feeling hotter and reacting more rapidly to changes in temperature. Response distributions are given in detail.

The bactericidal activity of natural sea-water on S. typhi is due to the combined effect of pH, salinity, toxic ions, presence of competitor and predator marine organisms, unidentified heat-labile toxic substances and competition for the limited food supply. Sea-water subjected to filtration and autoclaving lost the major part of its bactericidal activity. It is concluded that predators and competitors contribute significantly to the rapid death of S. typhi in raw sea-water. The addition of peptone decreases the bactericidal activity of sea-water. The fluctuations in the total number of competitors and predators in sea-water together with the fluctuations in the concentration of heavy metal ions may be affected by various factors. Such fluctuations are probably responsible for the variable bactericidal action of different sea-water samples.

Bathing in sewage-polluted sea-water carries with it a health risk in spite of the excessive dilution of pathogenic micro-organisms in the sea and the rapid self-purification process of sea-water. The natural purifying processes are incapable of coping with massive pollution problems and should not be relied on as the sole protection offered to users of sea-water.

The multiplication pattern of a temperature-sensitive (ts) mutant of bovine parainfluenza 3 virus was studied in hamsters and compared with that of a virulent virus strain. The ts mutant was recovered regularly from the nasal mucosa and not from the lungs, whereas the virulent virus multiplied in the lungs as well as in the nasal mucosa.

The serological response induced by the mutant was comparable to that obtained after inoculation of the virulent virus.

This ts mutant may be a potential candidate for a live intranasal vaccine against bovine parainfluenza 3 infection.

Six coronaviruses isolated in the U.S.A. have been inoculated into volunteers and all produced colds. Between 10 and 20 % of infected volunteers developed heterologous antibody responses after these and other experimental infections with coronaviruses. The haemagglutination-inhibition test with the OC43 virus strain was found to detect antibody rises after infection with a variety of strains.

Studies on normal adult sera taken between 1965 and 1970 revealed a high frequency of neutralizing antibody to one strain (229E) and a frequency of HI antibody to strain OC43 which fluctuated from year to year. Complement-fixing antibodies to these two viruses were also found, revealing an apparent increase in the activity of coronaviruses in the general population of the U.K., during the winter of 1968–9.

Investigation of a small series of cases of typhoid fever infected in a river between 1963 and 1970 revealed that all were caused by a single source, a carrier of a rare phage type of Salmonella typhi. The contamination of the river resulted from an incorrect sewage connexion with a surface water drain outfall into the river.

Influenza virus may be precipitated and aggregated by polyethylene glycol into clusters comprising ten to many hundred virions per aggregate. These aggregates are sparingly soluble and may be freed of contaminating polymer by washing in the appropriate buffer at room temperature or by precipitation in 30 % (v/v) ethanol at subzero temperatures.

Immunogenic studies in guinea-pigs of the virus in different states of dispersion revealed that the aggregated virus is the superior antigen to the virus in the monomeric form or in the dissociated state following treatment with ether.

Serum proteins from Mycoplasma gallisepticum culture medium could be detected on the organisms as a result of incubation at low pH. Only certain of the serum proteins, including IgG and IgM, were found, and the adsorption appears to depress the haemagglutinating activity of the organisms. There was no obvious effect on slide agglutination (SA) sensitivity but an incidental finding was that brief acid treatment enhanced the SA sensitivity of an antigen prepared from a young culture.

A simple and convenient particle tracer for studies of the effectiveness of isolation units and other places in limiting the airborne transfer of bacteria is described. Particles of potassium iodide 7–8 µm. diameter are generated by spraying from solution and collected on membrane filters. The particles can be identified by development with 0·1 % acid palladium chloride solution, when dark brown spots approximately 100 µm. in diameter are produced.

Values are deduced for the efficiency of isolation against airborne particulates, e.g. micro-organisms, of a variety of ventilation systems. The calculated values show reasonable correspondence with the limited experimental data available. Much better control and indication of the air flow is necessary if high degrees of isolation are required.

Airborne-particle transfer has been studied in a burns unit using potassium iodide particles. The observed rates of transfer were in good agreement with the values predicted by a theoretical model.

An estimate of the average transfer between rooms under conditions of normal activity and with correctly functioning ventilation showed that the isolation system was highly efficient, the proportion transferred being probably less than 1 in 105. However, the ventilation often did not function as designed and under these conditions the efficiency was reduced by a maximum of a factor of ten. These rates of transfer do not seem great enough to account for the high rate of cross-infection found in this unit.

The kill of Escherichia coli within 3 min. was studied in chlorine-demand-free water using sodium hypochlorite, monochloramine, dichloramine, halazone, chloramine T, cyanuric acid + sodium hypochlorite and cyanuric acid + monochloramine. The redox potential and the available chlorine were measured. The redox potential was found to be better correlated with the disinfecting property of the water than was the amount of available chlorine. For individual pure chlorine compounds, the measuring of available chlorine showed in general a somewhat better correlation with reduction of the bacteria than the redox potential showed.

During the period October 1968 to March 1969 echovirus type 18 was isolated from 83 patients investigated at Fairfield Hospital for Communicable Diseases, Melbourne. The illnesses most commonly associated with these isolations were aseptic meningitis, and fever with rash.

We believe that this is the first report of an epidemic due to echovirus type 18 and the first occasion on which this virus has been shown to produce disease in adults.

After oral contamination of conventional mice with high doses of Escherichia coli, Klebsiella pneumoniae or Pseudomonas aeruginosa the contaminant was recovered in abnormally high concentrations from the duodenum and caecum during the first few days. In this initial colonization phase, evidence of spread was obtained by culturing the cervical and mesenteric lymph nodes and spleen. Longer after contamination the intestinal concentration decreased to normal and spread stopped. In orally antibiotic-treated mice, the situation seen during the initial colonization phase in conventional mice occurred after a much lower oral contamination dose and persisted during the entire observation period of 2 weeks.

A single inoculation of pseudomonas vaccine protected mice against a 1 LD 100 challenge by nine different serotypes of Pseudomonas aeruginosa, 4 days after vaccination. Three inoculations of the same vaccine, given on consecutive days, protected mice for a longer time, against challenge by a wide range of Ps. aeruginosa serotypes, than the single inoculation of vaccine. The amount of vaccine inoculated only marginally influenced the non-specific response. F1 vaccines from eight serotypes of Ps. aeruginosa each induced protection against a different range of serotypes.

Antisera prepared against vaccinia and cowpox viruses were absorbed with purified suspensions of vaccinia virus, red cowpox and white cowpox viruses. They were then tested for their ability to neutralize the viruses, and to precipitate the virus soluble antigens.

The results showed that some virus specific antigens were not virus surface components and that some components were present on the surface of all three viruses. However, certain components were detected on the surface of vaccinia virus but not on the surface of cowpox virus, and vice versa. Some evidence for the existence of a vaccinia-specific surface component was also obtained.

Comparisons between results of cross-neutralization tests and immunodiffusion tests on the absorbed sera indicated that antibody to a number of antigens, including the classical LS, and the cowpox-specific d antigen play no part in the process of poxvirus neutralization.

Strontium chloride enrichment broth was found to be comparable to Rappaport broth for the recovery of a wide range of Salmonella serotypes from man, animals, meat products and effluents. With the exception of cloacal samples from reptiles, both procedures were superior to selenite F.

The performance of strontium chloride M and selenite F enrichment was improved when effluent samples were incubated at 43° C.

Strontium chloride M and Rappaport enrichment were superior to selenite F for the isolation of Arizona species from reptiles.

Strontium chloride B, strontium selenite and Rappaport broths were found suitable for the isolation of multiple Salmonella serotypes from sea water contaminated with abattoir effluents. The strontium chloride B and strontium selenite enrichment media were superior to Rappaport broth when samples were incubated at 43° C.

Modified bismuth sulphite agar was found superior to Salmonella-Shigella agar as a solid subculture medium.

The investigation of a food poisoning outbreak due to Salmonella typhimurium phage type 21 is reported.

The significance of the choice of sampling and isolation techniques in salmon-ellosis in man and animals is discussed.

Public Health Laboratory Service Working Group, Niels Skovgaard and B. Brest Nielsen. Journal of Hygiene (1972) 70, 127–40.

On page 132, legend to Table 4 should read Growth of Salmonella from various raw materials sampled from November 1968 to January 1970 in one factory, and which can be used in the manufacture of pig feed.

A. C. Ghosh. Journal of Hygiene (1972) 70, 151–60

On page 154, in footnote to Table 1;

For R = S. bredeney read B = S. bredeney