The connexion between radioactive fall-out and the fission products was demonstarted by Blifford, Lockhart & Baus (1956), and the connexion between radioactive fall-out and radioactive strontium was reported by Libby also in 1956. Previous to the publication by Santholzer, Macků, Podrimek & Horak (1958) and Santholzer (1959) of records relating to the increased radioactive fall-out in areas in Central Europe (50° 10′ N. lat., 15° 50′ E. long.) which were not far distant from the area occupied by these University buildings, we had already decided to follow regularly the strontium 90 (90Sr) content of cow's milk produced in the area concerned.

1. Children and their parents in a communal settlement (kibbutz) were followed for 14 months with special regard to the influences of streptococcal carrier rate, streptococcal infections, chemotherapy and heredity on the pattern of rheumatic heart disease.

2. Children with proven or probable heart disease showed the same streptococcal carrier rates as controls in spite of continued chemoprophylaxis with oral penicillin.

3. A single injection of penicillin, given to all kibbutz members on the same occasion, reduced the streptococcal carrier and infection rates to zero and maintained a marked drop for 3 months. Thereafter, the rates rose to higher levels than before. Courses of sulphamethoxypyridazine (‘Lederkyn’) given first to the total population and then to children only, caused only temporary interruption in the attack rate.

4. The prevalence of rheumatic heart disease in children of parents themselves affected was 2½ times greater than in controls exposed to the same environmental risks.

5. Affected children were more susceptible to streptococcal infections than controls with identical exposure.

Grateful thanks are due to Miss Pearl Weiskopf, B.Sc., for the statistical analysis. Without the close collaboration of Dr J. Yauluss, Nurses Tova and Ziva and the members of Kibbutz S this study would have been impossible. Thanks are also due to Lederle Laboratories Department of Cynamid International and their Israeli agent, Dr L. Goldshmidt, for the gift of ‘Lederkyn’, and to Mrs Rachel Kosh for help beyond the call of her secretarial duties.

Eighteen volunteers were given live adenovirus attenuated by passage in pig kidney tissue culture. Thirteen were given adenovirus Type 7 and five were given adenovirus Type 4. All volunteers who were given Type 7 and who had no homologous neutralizing antibody on inoculation showed antibody rises. Except in one volunteer not in isolation no signficant symptoms were seen.

It is suggested that adenoviruses attenuated in this way might be useful for large-scale vaccination programmes.

Sixty-six paired sera from patients suffering from mumps were examined with Sendai and mumps virus particle antigen: 50% showed a rise of complementfixing antibodies to mumps virus particle antigen only and the rest to both antigens.

This relationship was further substantiated by the occurrence of both antibodies in a proportion of the sera of 362 blood transfusion donors and 978 sera from antenatal patients.

The occurrence of both antibodies in patients' sera is discussed and the conclusion is reached that one of the components of the mumps antigen complex is indistinguishable from the essential components of the Sendai virus.

I am indebted to the Maternity Department of the Edgware General Hospital for supplying the antenatal sera, and to Dr Preston of the Regional Transfusion Centre, Oxford, for the blood donor sera.

Using a Dale organ bath and the ileum of passively sensitized guinea-pigs a specific sensitive reaction with as little as 1 μg./ml. of disintegrated whole cultures of various bacteria and 0·01 μg./ml. of purified Sh. dysenteriae and S. typhimurium polysaccharides was obtained.

More detailed study showed that 1 μg./ml. of Sh. dysenteriae degraded polysaccharide derived from the O antigen could be detected with consistency. Lower concentrations gave irregular results.

My thanks are due to the David Bruce Laboratory for supplying the antisera and the bacterial suspensions, to Prof. W. T. J. Morgan of the Lister Institute of Preventive Medicine for the antibody nitrogen determinations, to Dr D. A. L. Davies of the Microbiological Research Establishment, Porton, for the antigen preparations and to Corporals G. Willis and P. Brown, R.A.F., for much careful work in day to day experiments.

The problem of describing quantitatively the effective ventilation in a room when the air within the room is imperfectly mixed is discussed. It is suggested that the protection afforded by the ventilation to any given position against airborne contamination liberated at any other position can be best expressed in terms of the integrated exposure at the first point following liberation of a tracer substance at the second. This quantity is called the transfer index and its reciprocal the equivalent ventilation approaches numerically to the rate of supply of ventilating air as the mixing of air within the room approaches completeness. Nitrous oxide is a convenient tracer gas for making such measurements.

A method is also described whereby estimates of the transfer index can be made employing only such apparatus as is easily available in a reasonably well-equipped laboratory. This method employs acetone vapour as a tracer substance. The concentration of this vapour in the air is measured by the pH change produced in a dilute solution of hydroxylamine hydrochloride as it flows down a cotton wick exposed to the atmosphere.

A dose of 5 × 109S. typhi (strain Ty2) and S. paratyphi B (strain HB3) administered to white mice orally, caused an infection of various organs of the mouse, namely: spleen, liver, kidneys, lungs, gall-bladder, mesenteric lymph nodes, jejunum and of the blood stream. The percentage of infected spleens was higher than that of other organs.

With the above-mentioned dose of Ty2, the infection of the liver was found to be five times higher than that of the gall-bladder. The infection of the latter lasted for about 8–9 days, whereas that of the liver for 18–19 days.

The bacteria appeared in the various organs: liver, spleen, kidneys, and lungs in about 2 min. after oral infection, and in the blood stream after about 20 sec.

The speed and intensity of the invasion of micro-organisms from the gastrointestinal tract to the blood stream depends neither upon the volume of the dose (0·5 ml. or 0·1 ml.), nor upon the content of the mouse's stomach.

The M.I.D. for the blood stream of the mouse by oral infection is about 5 × 105 bacteria for Ty2, HB3 and AH6.

In blood samples collected by cardiac puncture 2–3 min. after oral infection, an average of 5 × 102 micro-organisms/ml. blood was found. The count of bacteria increased and reached its peak after 20 min. (about 3 × 103 bacteria). After that period, the number decreased: 1·6 × 103 after 1 hr., 8 × 102 after 2 hr. and 1·7 × 102 after 3 hr. In spite of this considerable decrease, the blood did not became sterile until after several days.

In the infected spleen (by oral infection) an inverse process was observed: at the beginning only a small number of micro-organisms was found (about 5 × 10/100 mg. spleen), but afterwards the number of bacteria increased (1·2 × 102 after 24 hr. and 5 × 102 after 4 days).

In mice infected by the subcutaneous route with a dose of 5 × 109 bacteria, the number of micro-organisms in the blood stream did not differ significantly from that found after oral infection, whereas infection by intraperitoneal route caused a severe infection. When 5 × 107 micro-organisms (LD50) were administered by intraperitoneal route, 107 bacteria appeared in the blood stream of the moribund mice while in the spleen about 4·1 × 107 were found.

The author wishes to express his appreciation to Prof. I. Gurewitch and to Dr R. Rozansky from the Department of Clinical Microbiology, the Hebrew University-Hadassah Medical School, Jerusalem, for their advice and criticism.

A complement-fixation test for acute poliomyelitis using unheated antigens derived from suckling mouse brain infected with poliovirus Type 1 or Type 2 is described.

The results of tests in 62 patients clinically diagnosed as cases of acute poliomyelitis in a recent epidemic and in 26 controls are recorded.

The CF tests were positive in 100% of 53 cases with poliovirus Type 1 and/or Type 2 in stool. A positive result was obtained in 23 (76%) of 30 cases whose sera were examined in the first 7 days of illness.

Negative tests of the initial serum samples were found in 15 (28·5%) of 53 cases, but all these became positive in titres of 40 or 80 on testing of convalescent serum.

In 31 (69%) of 45 cases whose sera were re-tested between the 3rd and 4th weeks of illness the CF antibody levels rose, reaching titres of 80 or 160 in most instances. Of the remaining 14 cases only one dropped in insignificant degree (from titre 320 to 160) and the 13 stationary results had been positive in titres of 40–160 on initial tests most of which were performed in the 2nd week of illness.

Homotypic CF antibody response without crossing was found in 37 (71%) of 52 cases with Type 1 or Type 2 virus in stool. In the cases of crossing the heterotypic antibody response was either transient, diminishing or stationary in all and in only low titre in most instances.

In 26 control cases there were seven positive CF tests, but one of these was nonspecific, five were in lowest titres, and one case appeared to have had recent poliomyelitis infection.

Heating the antigens did not broaden the reaction. It caused only slight loss of potency except in two cases in which the CF titre increased substantially.

The antigenic preparation described appears to be superior to antigens of other origin in the diagnosis of acute poliomyelitis by complement-fixation tests, as positive tests are recognized earlier in the illness and the titres are higher. Homotypic results were obtained in all cases and no instance of false negative occurred in this series.

I would like to thank the medical staff of the Cape Town City Hospital for Infectious Diseases for the trouble taken in collecting stools and paired sera, and Prof. Kipps for his interest in this work. I am indebted to Miss Karin Larssen for valuable technical assistance.

A new dulcitol–salicin–sucrose–iron–urea medium is described which, on the basis of a single-tube culture, tests the fermentation of three sugars, H2S production and urea hydrolysis.

On this medium 91% of 228 Salmonellae gave easily recognized characteristic reactions, simulated only by some strains of the Bethesda-Ballerup group. Proteus strains and most paracolon strains gave equally characteristic pictures.

The reactions of some other Enterobacteria are described. It is suggested that the medium is good enough to deserve extended trial in routine work.

A non-explosive mixture of ethylene oxide and Arcton 12 is described. This mixture is now available commercially in this country.

A sterilizing chamber and related equipment for use with this gas and a sterilizing technique are also described.

Some applications of ethylene oxide sterilization are briefly discussed.

Trials were conducted in the Sierra Nevada Mountains of California to test the effectiveness of 10% DDT dust in insecticide bait-box stations against the fleas of native diurnal rodents. The principle host species involved were the chipmunks Eutamias amoenus and E. speciosus, and the golden-mantled ground squirrel, Citellus lateralis. The important flea species were Monopsyllus eumolpi and M. ciliatus on chipmunks, and Diamanus montanus and Oropsylla idahoensis on ground squirrels. When baited daily for 12 days and furnished with 50 g. of 10% DDT dust, the bait-box stations reduced fleas strikingly within 24 hr., but very little residual control was obtained. A second application in which boxes were baited only twice weekly but for 28 days, also resulted in rapid knockdown and a residual control still effective 42 days after removal of the bait-boxes. The effect of the DDT was apparent at a distance of 400 ft. from the nearest bait-box due to the relatively extensive home ranges of the hosts. Although, in these trials, bait-box stations were spaced 100 ft. apart, 200 ft. spacing probably would be as effective with these hosts.