A simplified method for the detection of rubella-specific IgM in sera was developed involving HAI tests on only one fraction from a sucrose density gradient with and without treatment with 2-mercaptoethanol (2 ME). Slight trailing of IgG into the IgM fraction was shown to occur in patients with high titres of both IgG and IgM, but this could be detected by the 2ME treatment and did not affect the results.

By this test, rubella-specific IgM was found in all of 54 patients with a rash and a rise of rubella HAI antibodies. When the antigen and serum were incubated for 1 hr. before adding the RBC, specific IgM was found in all 51 sera taken between 5 and 40 days after onset, and in about half the sera taken between 42 and 77 days, but in none of 16 people known to have possessed rubella antibodies at least a year previously. When antigen and serum were incubated for 18 hr. before adding the RBC, specific IgM was found in all of 21 sera taken between 2 and 49 days after onset, and in 6 of 11 sera taken between 50 and 117 days, but not in 9 people known to have possessed rubella antibodies at least a year before. The method has been found to be very useful in detecting recent rubella among patients in early pregnancy.

The potentiality of calciferol (alone and combined with warfarin) for the control of commensal rats and mice has been examined in the laboratory. Nearly all animals fed on 0·1% calciferol for 2 days died. Though illness usually reduced food intake after the first 24 hr. there was no sign of aversion to the poison at 0·1 % – which is considered to be the lowest concentration suitable for use against Rattus norvegicus, R. rattus and Mus musculus in the field. There was some indication that resistance to warfarin in R. norvegicus may be correlated with susceptibility to calciferol. Toxicity tests with calciferol combined with warfarin indicated an additive effect between the compounds. No evidence for synergism was found however, although elsewhere there is some evidence for this.

A combination of calciferol (vitamin D2) and warfarin, each at 0·025% in medium oatmeal bait, failed to control six of seven house-mouse (Mus musculus L.) populations infesting urban and farm buildings. In three further treatments with both calciferol and warfarin at 0·05 % in dehusked canary seed bait plus 5% corn oil, mortality, estimated from the consumption of pre- and post-treatment census bait, ranged between 94·2 and 97·4%. Finally, among sixteen treatments done with calciferol at 0·1% and warfarin at 0·025% in various cereal baits, the best results (97·0–100%) were obtained in six treatments where the bait-base was whole canary seed; this was so whether the poison bait was applied directly or after a 3-day pre-baiting period. It is concluded that calciferol at 0·1 % plus warfarin at 0·025 % is an effective combination against house-mice, especially when used with whole canary seed. The role played by warfarin in the poison mixture needs to be investigated further.

The effectiveness of calciferol (vitamin D2) against Rattus norvegicus was investigated in field trials on twenty-three farms with rat infestations partly resistant to warfarin. At 0·01% combined with warfarin at 0·025% no rodenticidal effect of the calciferol was discernible. At 0·025% with warfarin at the same concentration, results were better, but not appreciably better than is often obtained with warfarin alone against resistant rat populations. When the concentration of calciferol was stepped up to 0·1%, four out of five treatments in which the poison was applied directly gave complete control. The fifth may have partly failed because of poison shyness caused by under-baiting. Five out of six more treatments done after ‘pre-baiting’ were also successful. The sixth failed for reasons unconnected with the choice of poison.

Six further infestations that were not responding adequately to warfarin treatments were quickly controlled when, in three instances, calciferol at 0·1% was used instead and, in three more, it was used together with warfarin. It is concluded that calciferol at 0·1% is an effective poison against R. norvegicus either combined with warfarin or not, but that because at 0·1% its effect is subacute rather than chronic, there may be a case in some environments for using it only after pre-baiting.

The ability of Aureobasidium pullulans, Cladosporium herbarum and Cryptostroma corticale to produce local lesions in the rabbit was examined. Both C. corticale and A. pullulans can survive in vivo and produce the inflammatory response typical of mycetoma. C. herbarum failed to grow or survive in vivo.

Between 1961 and 1972, 4547 independent strains of Staphylococcus aureus isolated from one hospital were examined for phage type. After 1967 there was a decline in the number of strains received, which we consider reflects a decline in the number of infections in the hospital, and which was largely accounted for by a great reduction in the number of strains in four ‘epidemic’ types. Overall, the number of multiple-resistant staphylococci received also declined; this was in part due to the decline in the epidemic types and in part to a reduction in the proportion of multiple-resistant strains of all types.

Most babies are colonized by the predominant strains of Escherichia coli present in their own mother's faecal flora. Those babies who did not acquire their maternal faecal flora acquired strains of E. coli belonging to a small number of the possible serotypes. Moreover, the same serotypes were found in several babies and other mothers, suggesting spread within the ward. These few strains included some of the O groups which had previously commonly been found as urinary pathogens. These strains may have increased potentialities for colonization of human bowel. Antigenic and biochemical variation was observed among the strains.

The degree of immunity due to cross-reactions between antibody to influenza virus A/Hong Kong/1/68 and A/England/42/72 was studied in ferrets. Ferrets were immunized with the viruses by either live infection or by inoculation with inactivated virus vaccines. The vaccines were given with Freund's incomplete adjuvant or were given to ferrets previously infected with influenza virus A/PR/8/34. As a result of these immunizations the animals all produced similar titres of serum HI antibody to the immunizing virus, although the degree of crossreaction with the other virus strain was variable. After immunization the animals were challenged by infection with an A/Eng/42/72-like virus and their degree of immunity was measured. It was found that the greatest immunity was in ferrets previously infected with the homologous A/Eng/42/72 virus. Animals previously infected with A/HK/68 virus also showed a measurable degree of immunity to A/Eng/42/72 infection, and this was greater than that found in animals given inactivated virus vaccines. The immunity produced by the vaccines was approximately equal, regardless of which vaccine or method of immunization was used. Thus, live infection produced a more effective, broader immunity than did the use of inactivated virus vaccines.

An analysis was made of the dose-response of several populations of Rattus norvegicus fed upon baits containing 0·005% warfarin for various numbers of days. Warfarin-susceptible populations fell within a narrow range, with LFP50s and LFP98s (lethal feeding periods in days to obtain 50% and 98% mortalities respectively) of up to 3·0 and 5·0 days respectively. The probability of an individual rat from these populations surviving a six-day feeding period was estimated at 0·003 or less. Populations with responses falling beyond these limits were regarded as warfarin-resistant.

Six of nine populations of R. norvegicus, from England, Germany and the United States, were determined to be warfarin-susceptible within the narrow limits given above. In all six cases, no animals survived the six-day WHO feeding test for anticoagulant susceptibility. In three populations from the United States, where rats survived six days feeding, their population responses clearly fell outside the measures given above. It is suggested, tentatively, that anticoagulantresistant Norway rat populations be defined as those whose LFP50 and LFP98 exceeds 3·0 and 5·0 days respectively, and in which the probability of an individual animal surviving a six-day feeding upon 0·005% warfarin is 0·01 or more.

The clearance of neomycin and kanamycin from the intestines after stopping oral supply has been determined in mice. Both antibiotics, although given in different doses, were excreted in essentially the same way; the clearance being a little faster than logarithmically in both cases. The importance of this observation with regard to isolation and the moment of reconventionalization is discussed.

Normal bovine milk and whey was mycoplasmacidal for 6 of the 13 strains of bovine T-mycoplasmas examined. The in vitro assay used also demonstrated no killing of the human, canine and simian T-mycoplasma strains after 4 hr. incubation. However, there appeared to be some cow-to-cow variation in possession of this activity, and following E. coli endotoxin stimulation of the mammary gland the activity was considerably reduced.

Whey from three normal cows was fractionated on a Bio-Gel A 1·5 m. column and the mycoplasmacidal activity of the resulting five peaks assayed. Only the second peak, peak B, contained activity and was characterized as the only peak containing bovine IgA. The active component in whey, however, was found to be heat stable at 60° C. for 60 minutes and to pass through a dialysis membrane. This is inconsistent with it being immunoglobulin.

The nature of the antibodies detectable by the microscopic agglutination test for bovine leptospirosis was examined. Density gradient ultracentrifugation, gel filtration and disulphide-bond-reduction experiments indicated that antileptospiral agglutinating activity was present in both IgM and IgG immunoglobulin fractions. This was confirmed by selective precipitation of specific antibody classes and ion-exchange chromatography.

A number of outbreaks of food poisoning attributed to Bacillus cereus have been reported recently and all have been associated with cooked rice usually from Chinese restaurants and ‘take-away’ shops.

Tests were made to assess the heat resistance of B. cereus spores in aqueous suspension, the growth of the organism in boiled rice stored at temperatures in the range 4–55° C., and the effect of cooking and storage on the growth of the organism in boiled and fried rice. The spores of B. cereus survived cooking and were capable of germination and outgrowth. The optimum temperature for growth in boiled rice was between 30° and 37° C. and growth also occurred during storage at 15° and 43° C.

To prevent further outbreaks it is suggested that rice should be boiled in smaller quantities on several occasions during the day, thereby reducing the storage time before frying. After boiling the rice should either be kept hot (> 63° C.) or cooled quickly and transferred to a refrigerator within 2 hr. of cooking. Boiled or fried rice must not be stored under warm conditions especially in the range 15–50° C.

Two outbreaks of epidemic vomiting are described. One affected 107 students and staff at a college of education out of a total of 398 persons. The other affected 172 pupils and staff out of 357 at a secondary school. Evidence is presented that in both cases infection was acquired in the dining hall of the institution concerned but no specific item of food was found as a likely cause. The literature is reviewed. Possible mechanisms of spread are suggested.

A comparison of twelve strains of Mycoplasma dispar by the metabolism inhibition and indirect haemagglutination tests has shown them to form a serologically homogeneous group of micro-organisms. The twelve strains vary in their haemagglutinating activity against erythrocytes from different animal species, and certain of the strains can be distinguished by the erythrocytes they agglutinate. Haemagglutination may thus provide a method by which certain strains can be typed. The erythrocyte receptor site does not appear to contain sialic acid and is not sensitive to proteolytic enzymes. On the mycoplasma cell two attachment sites have been demonstrated. One, by which it attaches to sheep and bovine erythrocytes, is a protein or contains a protein moiety. The chemical nature of the other attachment site, by which M. dispar attaches to rabbit erythrocytes, is unknown.

The relative acceptance of various plain foods by wild house-mice (Mus musculus L.) was compared in laboratory choice tests. The palatability of glycerine and six oils, each included at 5% in pinhead oatmeal, was compared in a similar manner.

The most favoured food was found to be whole canary seed (Phalaris canariensis). Pinhead oatmeal and wheat were also comparatively well accepted. Glycerine, corn oil, arachis oil and mineral oil were more palatable than either olive, linseed or cod-liver oils.

The results of the choice tests are considered in relation to the use of poison baits for the control of free-living mice.