Either triplicate or paired sewer swabs put down at sixty manholes were examined after 24, 48 or 72 hr. periods of enrichment at 37° C. in a standard tetrathionate medium (medium C) and in two new tetrathionate modifications—medium A being a combination of tetrathionate broth and ingredients of Wilson and Blair's medium, and medium B similar but containing only half the amount of the Wilson and Blair's ingredients, and in addition 1% sodium lauryl sulphate.

Salmonellae were isolated from thirty-nine sites: there were three double isolations of salmonellae.

The richest growths of salinonellae were obtained from medium B and the poorest from medium C. Medium C however yielded more isolations from the smaller sewers than medium B: the converse held true in the trunk sewers.

An optimal 48 hr. enrichment time for sewer swabs was demonstrated in the case of medium A. No optimal time was found for either of the other two media. Platings at the optimal enrichment time from medium A yielded more salmonella isolations than the combined 24 and 48 hr. platings from medium C.

The nasal carriage of 407 mothers before, during and after admission to a maternity hospital and that of their babies during and after hospital stay was investigated together with the nasal carriage by the hospital staff.

The nasal carrier rate among mothers admitted to hospital was 38%, 40% of these strains being resistant to penicillin.

The nasal carrier rate among the nursing staff was 38 and 72% of these were resistant to penicillin.

If a population is swabbed only once approximately 25% of the carriers will be missed. Those showing slight carriage were no more likely to be missed than those showing heavy carriage. The concentration of organisms in the nose is evidently varying continuously.

Heavy carriers are no more likely to transmit than light carriers and it is therefore not right to report on the profusion or otherwise of growth if that implies a greater chance of transmission.

The biggest increase in resistance among nursing staff strains occurred in the non-typable group which could be explained by resistance to phage developing concurrent with resistance to antibiotics.

The difference in phage-distribution between patient and staff strains centred in group II which formed 19% of patient strains but only 7% of hospital strains.

The carrier rate was no higher for those with a history of hospital admission within 12 months or without a history of staphylococcal sepsis.

Those giving a history of penicillin therapy had the same resistance rate as those without a history of such therapy.

1. A study of the various aspects of passive tetanus immunization and combined active and passive immunization in different animal species has been undertaken.

2. The criteria on which conclusions have been based consisted of titration of antitoxin serum levels and mouse and guinea-pig protection tests using a challenge of 20 M.L.D. of tetanus toxin.

3. A study of the rate of elimination of heterologous tetanus antitoxin in normal and sensitized animals showed that the latter eliminated antitoxin more rapidly from circulation after subcutaneous injection but no difference could be detected following intravenous administration. More important is the profound loss of serum antitoxin in both animal groups from the seventh day onwards.

4. The rate of elimination in humans receiving 1500 units of horse antitoxin subcutaneously was approximately the same in normal subjects and those who had been previously exposed to horse serum.

5. The interference of an active primary immune response by the simultaneous injection of antitoxin in rabbits was consistently more marked with fluid toxoid than with adsorbed toxoid. Thus, combined active and passive immunization of persons who have never been actively immunized, is not recommended, especially with fluid toxoid.

6. Administration of adsorbed toxoid 7 days or more after passive immunization with heterologous antitoxin does not interfere with the primary immune response.

7. Comparison of the immunizing potency in rabbits of fluid and adsorbed toxoids showed that the latter was far superior.

8. Homologous antitoxin was demonstrated in man and animals to be immunologically superior to the heterologous type in every respect. It persisted unchanged in a therapeutically active concentration for at least 3 weeks in humans and its protective action in guinea-pigs was at least 100 times greater than heterologous antitoxin. Since homologous antitoxin can be used in low doses it will not interfere with the primary immune response in combined immunization.

9. A recommended prophylactic dose of homologous antitoxin for man would be 200–250 units.

1. In our hands the assay of a plague vaccine, in terms of its power to protect mice against what was hoped to be a standard challenge, was found to be impracticable.

2. Assay by mouse protection tests in terms of a Standard vaccine was found to be possible, but it proved to be a very time-consuming procedure and demanded the use of an almost prohibitively large number of mice for a sufficient number of replicate tests which are required to offset the variability in the method. Theoretically a single test might be adequate if the numbers of immunized mice were very large, but there are obvious limitations to the numbers of mice that can be included in a single test of this nature.

3. The Ouchterlony plate technique proved to be useful in indicating the antigens present in a particular vaccine, but not on a strictly quantitative basis.

4. The vaccine prepared from the virulent human strain of P. pestis was found to protect mice more efficiently than those prepared from avirulent strains and when the protective potency was expressed in terms of content of antigen and high molecular weight substances the vaccine prepared from the virulent culture was found to be even more potent than the Standard acetone-dried vaccine.

5. The use of formalin as a preservative results in some loss of potency of a vaccine but, provided the strain of P. pestis used for the preparation of the vaccine is highly virulent, this need not be serious and is offset by a number of advantages.

1. Some of the biological and physical properties of one member (FES) of an inter-related group of viruses were examined and compared with the Saukett strain of poliovirus Type 3.

2. The accumulated data of particle size, immunological relationship, and host tissue and cell tropism indicates that this is a naturally occurring non-neurotropic strain of poliovirus Type 3. It shows a slight immunological difference from Saukett, and also differs from it in temperature stability.

3. The significance of four different isolations of this agent in a brief period is discussed.

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.

1. The use of sodium glutamate as a medium for freeze-drying Lact. bifidus significantly enhanced the stability of the dried product, especially the heat stability.

2. The optimal concentration of sodium glutamate, as a drying medium, was found to depend on the bacilliary concentration; the higher the concentration of the bacilliary suspension used the higher was found to be the optimal concentration of the sodium glutamate.

3. It was possible to classify various drying media according to the degree of sublimation of the product during the process of freeze-drying. Two types were observed; in the first, which included sodium glutamate and glucose, the sublimation rate diminished with the increasing concentration of the medium, whereas in the second group, which included polyvinyl pyrrolidon K 90 (PVP), soluble starch and dextran, no such diminution was observed when the concentration of the medium was increased.

4. By the combination of sodium glutamate or glucose with a medium belonging to the second group sublimation was found to be promoted.

5. The stabifity-conferring effect of sodium glutamate on dried Lact. bifidus was markedly enhanced when the glutamate was combined with a drying medium belonging to the second group. This effect is attributed to a desiccation-promoting property of the latter medium.

6. Lact. bifidus as a freeze-dried preparation showed a somewhat better survival rate when sealed in air than when sealed in vacuo. In the case of other anaerobic organisms tested there was no significant difference in the survival rates under the two methods of storage.

1. Moore's gauze swabs have, in our hands, been shown to be a reliable instrument for the survey of salmonella infection in the environment of two food premises.

2. A large bakery was demonstrated to be regularly contaminated with salmonellae. Thirty-one floor gully swabs out of 111 (27·9%) were positive for salmonellae. Little spread of infection to the general public was experienced.

3. Staff infection with salmonellae was shown to occur in this bakery. Fifteen positive specimens of staff sewage out of 93 were obtained (16·1%). There was little evidence of prolonged contamination of the sewers with salmonellae. Staff infections were probably, therefore, of short duration. The staff probably became infected from contaminated goods in the bakehouse. Rat contamination of sewers was excluded by water trapping.

4. It is not thought that regular examination of staff excreta would be a profitable means of discovering carriers or of preventing contamination of the products. The frequency with which such examinations would have to be performed to discover short-term excreters would be administratively impossible.

5. Of 274 swabs from gullies in abattoirs, 111 were positive for salmonellac (40·5%). Twenty-one different serotypes were isolated. Seventeen of these serotypes are known to occur in animal feedingstuffs.

6. Parallel examination of abattoir swabs and excreta from human infections for S. typhimurium, coupled with phage-typing of the strains, provided information of the geographically local nature of much sporadic illness due to this serotype. Of a total of 30 typable strains, 23 belonged to phage-types found in the abattoirs, or on local farms. Sporadic incidents were represented by 25 of these cultures, 18 of which corresponded in phage-type to those found in the abattoirs or in local farm animals. The phage-types of S. typhimurium isolated from the slaughter houses not infrequently corresponded in timing with the strains isolated from human infections.

1. An outbreak of food poisoning due to S. typhimurium and S. thompson is described.

2. These same two serotypes were found in trifle eaten by the victims.

3. S. typhimurium was found in the stools of four members of the bakery staff and in the stool of one member of the grocery staff handling luncheon meat eaten by those affected.

4. S. typhimurium was isolated from drains in the bakery.

5. The phage-type of S. typhimurium found in the food handlers, drains, trifle and victims of the outbreak was the same.

6. The phage-type of S. thompson found in the trifle was identical with that found in the victims of the outbreak.

7. The phage-type of both salmonellae suggested an egg product source.

8. It is surprising how infrequent these outbreaks are, having regard to the very frequent opportunity for the contamination of confectionery products in bake-houses.

1. Apart from strain identification of V. cholerae for epidemiological studies by phage-typing and determination of their S-R dissociation cholera bacteriophages may be utilized for other valuable diagnostic aids in the laboratory.

2. The universal susceptibility of V. cholerae strains to group IV cholera bacteriophage and universal lyso-resistance of El Tor vibrios to it provide a specific method for differentiating between the two species of vibrios. This test is simple and convenient for routine diagnostie use and should be of special value for identifying non-haemolytic El Tor vibrios, which are otherwise liable to be missed.

3. The marked insensitivity of the NAG vibrios to cholera bacteriophages, particularly their total insusceptibility to the phage of group II, enables these strains to be readily distinguishable from V. cholerae.

4. Cholera bacteriophages which are stable on maintenance and storage in the laboratory can conveniently be supplied absorbed on filter disks for the use of the smaller laboratories.

1. In one Australian study area where the selection pressure of annual epizootics of myxomatosis has been extremely high, the innate resistance of the rabbits was found to have increased to such an extent that only 26% died when inoculated with a strain of myxoma virus which kills 88% of genetically unselected rabbits.

2. The level of innate resistance in a rabbit population varies with the total experience of the disease.

3. In combined field and laboratory trials it was shown that the mortality rate in the field is influenced by innate resistance at least as much as under the sheltered conditions of an animal house. The effect was apparent with both an attenuated and a highly virulent strain of virus.

4. The moderately high ambient temperatures during the field experiments probably contributed to the sparing effect.

1. The incidence of infectious hepatitis calculated from official notifications fluctuated between 5·7 and 11·4 per 10,000 during the years 1949–57, while reports of the Workers' Sick Fund indicated a rate three to four times greater. The highest rates were between the ages 1 and 9, two-thirds of the cases being under 10. Mortality was very low.

2. Highest attack rates were seen under conditions of crowding, i.e. in agricultural schools, communal settlements and new immigrant towns. This fact, together with the winter peak of incidence, suggests a contact-respiratory form of spread.

3. Immigrants, regardless of country, showed particular susceptibility during their first year or two in Israel. In the long run there was no difference in attack rate between immigrants from Western and from Middle Eastern countries, in spite of the known endemicity of the disease in the Middle East. In communities such as those from Yemen and North Africa, with large families and with, on the whole, a lower economic status, the mean age at onset was significantly younger. Among the non-Jewish population, the incidence was lower than expected due partly to under-reporting and partly, perhaps, to a mild form of the disease in the very young.