1. If lysogenicity is used in conjunction with sensitivity to a set of phages aa a tool for phage-typing, a further subdivision of the phage types of Salm. paratyphi B becomes possible, and also the types fall into a number of natural groups. When lysogenicity is tested by growth of two types in mixed culture, phages are produced which by their characteristic host ranges reveal a subdivision of types, parallel and complementary to the subdivision found by a study of lysogenicity. These phage reactions therefore possess a biological significance not entirely empirical.

2. The method of Craigie & Yen, which made possible a great advance in phage typing of Salm. typhi by means of preparations derived by adaptation from a single phage, has not yet been shown to be applicable to the typing of Salm. paratyphi B (Felix & Callow, 1951). As some of the typing phages used in the Felix & Callow system are identical with certain ‘natural’ phages derived from lysogenic strains, the lysogenic character of the types they reveal may be used in conjunction with these sensitivity tests as characteristics of phage types, if the set of phages is increased by addition of a few, shown in Table 1. This suggestion was made to the International Committee for Enteric Phage Typing in 1952.

3. In addition to the demonstration by the direct method of phages carried by lysogenic strains of Salm. paratyphi B, phages derived from mixed cultures of different types are characteristic of some phage types. Further development of the use of such phages and study of their nature and origin demand further research. Until further investigations have been made, the subdivision of phage types which they reveal must be regarded as tentative.

4. Strains from a large outbreak of paratyphoid fever, which could not be typed reliably by the method of Felix & Callow, possessed peculiar lysogenic properties which, together with certain phage reactions, justify their designation as a new type, ‘Sittard’. These strains can be identified if phages derived from tests of lysogenic power are used in addition to those of the Felix & Callow system. A number of strains from other sources, diagnosed as type ‘Sittard’ by their sensitivity to phages, were shown to possess lysogenic properties characteristic of the type.

5. A few other strains, shown in a similar way to represent new types, are described.

Field observations supplemented by laboratory tests were carried out on the occurrence of myxomatosis at two sites with contrasting environments near the northern limit of rabbit infestation in Australia, during the period May 1952 to April 1953.

In spite of the very low incidence of cases of myxomatosis observed in wild rabbits during that period great reductions in the rabbit population occurred.

Analysis of the results of serum surveys indicates that myxomatosis was present and caused minor unobserved epizootics during this period, The overlap in this area of rabbit breeding and active transmission of myxomatosis probably led to a high death rate in the sub-adult rabbit population.

In spite of continued reintroduction of fully virulent standard virus into the areas, all strains of virus recovered were somewhat attenuated. There was a suggestion that at Texas the degree of attenuation increased during the study period.

Sex ratios and data on reproduction are presented for the 1488 rabbits shot at the two areas. Recovery from myxomatosis appeared to have no adverse effect on the fecundity of the female rabbit.

1. The in vitro properties of 214 strains of Proteus organisms isolated from dogs, cats, cattle, pigs, birds and other domestic and captive wild animals were examined.

2. The majority of strains were P. mirabilis, 23% being P. vulgaris and 4·7% P. morganii.

3. P. vulgaris was found more frequently in pigs and cattle than in other animals.

4. Biochemical varieties of the Proteus group occurring in man have been found in animals.

5. The action of Proteus strains on red blood cells was examined and strain differences observed.

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.

During the discussion of a paper presented by the author to the Society for Water Treatment and Examination at Sheffield in 1952, it was noted that several water bacteriologists were confirming, with a high degree of success, presumptive positive tubes in the coliform test as Bacterium coli type I after incubation for 6 hr. only in MacConkey broth at 44° C. (Taylor, 1952).

An investigation into the classification of strains of Shigella sonneiby the method of phage-typing (using unadapted bacteriophages) is described.

829 strains, obtained during 3 years from twelve regions in England (including Monmouthshire) were examined by a standard technique. There were fifty-two outbreaks (involving 587 strains) from which two or more strains were isolated.

Results confirmed the finding by Hammarström in Sweden that such classification was possible, strains falling into twenty phage-types of which thirteen were found more than once. All strains were typable, 74% belonging to the same type. In forty-seven outbreaks the phage-type was uniform, the commonest type occurring in thirty-eight of these. In five outbreaks the phage-type was not uniform.

It is concluded that this method of phage-typing, because of evidence of type instability and because the majority of strains belong to the same phage-type, has little practical value as a routine procedure in the control of Sonne dysentery in this country.

1. Direct conglutination has been demonstrated with Rickettsia burneti.

2. Sera from human volunteers inoculated with killed suspensions of R. burneti and from persons who had recovered from an attack of Q fever as well as sera from a small number of healthy blood donors were all examined by the direct conglutination reaction, the haemolytic-complement fixation test and the direct agglutination test. A good correlation was found between the titres of the direct conglutination reaction and the haemolytic complement-fixation test but the results with the direct agglutination test were unreliable.

1. Requirements for a heat-stable smallpox vaccine are suggested.

2. Sheep lymph dried from the frozen state retains its potency at 22 and 37°C. better than aqueous, glycerinated or lanolinated suspensions of lymph. Dried crude lymph is not, however, sufficiently stable for use in tropical areas; it is also liable to vary in stability from batch to batch. No better results were obtained by prolonging secondary desiccation.

3. Phenol in low concentration is deleterious to vaccinia virus stored in the dried or liquid state at 22 and 37° C.

4. Dried vaccinia virus stored under nitrogen loses potency more rapidly than when sealed in vacuo, even when precautions are taken to rid the nitrogen of traces of oxygen and moisture.

5. A number of suspending media were examined for their preservative influence on purified vaccinia virus. None was effective in the liquid state, but all protected the virus against the lethal influence of freeze-drying. In the dried state, these media varied in their ability to protect the virus during storage at 22 or 37° C. The best results at both temperatures were obtained with virus freeze-dried in 5% peptone. This medium also protects the virus well at 45° C. Different types of peptone were equally effective.

6. Virus dried in 5% peptone still gave a full quota of successful primary vaccinations of children after storage for 12 months at 22° C., or for 4 months at 37° C.

7. Using partially purified sheep virus dried in 5% peptone, a vaccine can be produced which shows a high degree of resistance to heat, is relatively free from bacterial contamination, and is easy to reconstitute after prolonged storage. These results are highly reproducible.

The cytoplasmic inclusion bodies produced by fowl-pox virus in the chorioallantoic membrane of the egg consist of a mass of virus particles, frequently surrounding an apparently normal component of the cytoplasm. Finely granular or filamentous material is seen in the centre of the inclusion and round the more central virus particles into whose structure it appeared to be incorporated. The inner virus bodies consisted of a granular core surrounded by a single membrane. The outer virus bodies consisted of a cortical layer 20 mμ thick, enclosing a space in which lay a core with a granular centre.

A series of comparative assays of two pertussis vaccines was carried out by the mouse intracerebral method, using litter-mates and placing one member of each litter on each dose.

A statistical analysis of the results by the method described by Irwin (1950, p. 231), was carried out, making due allowance for the use of litter-mates. A slight increase of accuracy was found in five out of six assays, but this did not reach the 5% level of significance. Any real increase of accuracy must have been small. The results show that, as far as these tests are concerned, there is no advantage in the use of litter-mates, particularly when one takes account of the large amount of additional work necessary in the animal house.

Workers in factories and a postal sorting office were questioned concerning their subjective thermal sensations, and the replies assessed according to a scale of standard sensations. Measurements of the thermal environment were made concurrently. The investigation was confined to workers engaged in light or sedentary activity during summer months in southern England.

The upper limit of the comfort zone is determined in terms of the temperatures at which more than 20% of people questioned experienced thermal discomfort.

Discontinuities in the linear relationships between thermal sensation, described on a numerical scale, and the thermal indices of the environment are shown to occur under conditions which suggest the onset of sweating beneath the clothing. The comfort zone is also determined in terms of these critical temperatures.

The regression constants relating thermal sensation to thermal conditions are determined, and the optimum conditions for comfort are deduced. The accuracy of prediction of thermal sensation from thermal measurements is examined.

The importance of clothing in requirements for thermal comfort is illustrated in two ways. Postal workers wearing regulation uniform were found to require conditions cooler than those required by factory workers wearing clothing of their own choosing. Male and female factory workers were found to require thermal conditions not significantly different, this being attributed to their selection of clothing appropriate to their personal thermal requirements.

I am indebted to Prof. G. P. Crowden for granting facilities for this research and for encouragement throughout. Dr T. C. Angus and Dr T. Bedford gave valuable advice, and Mr P. J. Williams rendered technical assistance. The co-operation of the managements and workers at the factories was greatly appreciated.

The returns relating to naval personnel who were reported to the Admiralty to have acquired non-surgical jaundice between 1944 and 1947 were examined.

Where the dates of onset of illness and of inoculation were available, the numbers who developed the illness within 11–40 days of inoculation were greater than the numbers to be expected if there was no association between the dates of onset of illness and the dates of inoculation. During 1945 the observed numbers were also greater than the expected numbers when 41–70 days intervened between inoculation and the illness.

The interpretation and practical implications of the findings are discussed.

This paper is published by kind permission of the Medical Director General of the Navy, Surgeon Vice-Admiral Sir Alexander Ingleby-Mackenzie.

I am indebted to Dr F. O. MacCallum for his continued interest and for invaluable suggestions; to Dr J. O. Irwin for scrutinizing the script; to Miss H. M. Ferres who applied the statistical tests to the figures in Table 1; to Surgeon Commander M. A. Rugg-Gunn, Royal Navy, for the information about the ratings' pay books, and to Senior Commissioned Wardmaster J. L. T. Burns, Royal Navy, and Sick Berth Petty Officer (L) D. E. Lee, Royal Navy, who tabulated the numerical data.