An examination was made of 200 Wassermann sera, thirty-eight sera from typhoid, twenty-five from paratyphoid B and thirty-one from tuberculous cases, for somatic agglutinins to a range of Salmonellas representative of the O groups then available.

In the Wassermann sera O agglutinins, except to Bact. typhosum and Bact. paratyphosum B, were rare, and the titres against these organisms were low, attaining a titre of 1: 80 against Bact. typhosum in one serum only.

The sera of the enteric cases mostly possessed agglutinins to both Bact. typhosum O and Bact. paratyphosum B O. Cross-relations with Bact. paratyphosum A, Bact. london and, to a less extent, Bact. paratyphosum C, were common in the typhoid sera. Otherwise there was no evidence of relation amongst the somatic groups tested.

The response to T.A.B. inoculation of fifteen individuals suggested also the relation of some organism in the vaccine to Bact. london and its probable lack of relation to the other somatic groups.

There was no evidence of increased frequency of Salmonella agglutinins in tuberculous cases.

The cross-relations of the Salmonellas was found to be due to the possession of minor antigenic components and not to possession of X antigen, which was absent from the suspensions used. X agglutinins were not more frequent in the pathological than in the Wassermann sera.

The relation of these findings to the diagnostic agglutination test is discussed, and the possibility of error consequent upon the use of suspensions containing X antigen is pointed out.

The globe thermometer was designed by H. M. Vernon as a simple instrument that will give a more reliable measure of the comfort of a room than the ordinary wall thermometer. When the room is heated by some system of low-temperature radiation, such as hot-water pipes, and when the amount of air movement is not excessive, the globe thermometer is probably as good as any single simple instrument can be. But it has never come into general use because there are conditions under which its indications may be very misleading to the layman.

The occurrence in this country of an epizootic disease among field-voles (Microtus agrestis), resembling tuberculosis in its anatomical features but due to an acid-fast bacillus different from the tubercle bacilli found in other species of warm-blooded animals, has raised several interesting questions. One of these is the relative susceptibility of the field-vole, and other species of wild rodents belonging to the family Muridae, to the bovine, human and avian types of tubercle bacilli and the possibility of using any of these species in place of the rabbit for differentiating between the three types. Some work on the subject was done by me in the year 1923, the rodents tested being field-voles and wood-mice (Mus sylvaticus). These experiments, reported in 1937, showed that the field-vole is highly susceptible to bovine bacilli, and can also be infected with human bacilli, though with less certainty and less severity than with bovine bacilli. The wood-mouse is susceptible to bovine and human bacilli, perhaps more so to the former than to the latter, and stands in an intermediate position between the vole and the white mouse in its susceptibility to mammalian tubercle bacilli.

In June 1938 the writer obtained three rats from Dr Gye and Dr Knox which had been previously infected with the “Pyogenic Virus” received by them from Dr Woglom (Woglom & Warren, 1938a). Pus from these rats was spread on plates of the writer's “special medium” for the isolation of pleuropneumonia-like organisms. No bacterial organism had been detected in the pus which, however, was full of granules and showed some filaments in the dark-ground preparation; after 6–10 days of incubation the plates were crowded with tiny colonies. They proved to be colonies of a pleuropneumonia-like organism, and the finding was recorded in an appendix to a recent paper by the writer (Klieneberger, 1938). At the edge of the growth from the seeded pus, where unhampered development was possible, the colonies showed a granular structure with a well-marked dense centre (see Fig. 1). No other organism was isolated from the lesions. More rats were now infected from the pus and all developed abscesses in the way described by Woglom & Warren (1938a, b). From these lesions the same culture was obtained (to be referred to as “Woglom strain I”). Since June 1938 up to date the pyogenic agent obtained from Dr Gye (to be referred to as “original agent”) has been transferred from rat to rat by subcutaneous injection of the crude pus. So far, forty-five rats have been infected with this agent; they all developed abscesses, and the pleuropneumonia-like organism was invariably isolated from the pus. In thirteen of these rats spleen culture was attempted, and the pleuropneumonia-like organism was obtained from nine out of these thirteen spleens. If the spleen culture was positive, subcutaneous injection of a suspension of spleen produced an abscess, while a culturally negative spleen had no effect if injected.

Still another instance is reported where an agent resembling the viruses has ultimately proved to be an organism which can be cultivated, but only in media containing a high proportion of serum.

The British Standard Technique for Determining the Rideal-Walker Coefficient of Disinfectants (no. 541—1934), in laying down the procedure to be adopted with regard to the test typhoid bacillus culture, recommends that a fresh culture be obtained each month from the National Collection of Type Cultures. In all probability this is the best procedure; it does, however, sometimes happen that a test is required urgently when a fresh culture is not available. The following notes upon our own experience in maintaining cultures may therefore be of some interest. It is our practice to obtain fresh cultures whenever we are called upon to carry out other than routine tests unless a recent one has been obtained, and many of these cultures have now been running for a number of years. On the arrival of the culture from the N.C.T.C. it is subcultured on to an agar slope and “incubated” at room temperature in a dark cupboard. 2% agar is used in a broth prepared by the tryptic digestion of ox heart. Further subcultures are made at intervals of one month. It is our usual practice to start a series of broth cultures from such slopes not less than 14 days after sowing.

In a recently published paper (Kermack & McKendrick, 1937) the observational data relating to epidemics of ectromelia in populations of mice maintained under experimental conditions (Greenwood et al. 1936) has been analysed in the light of a mathematical theory of epidemics developed by us during recent years (Kermack & McKendrick, 1927, 1932, 1933, 1936). It was shown that the life table giving the chance of mice surviving for various lengths of time in infected communities is very closely represented by a formula calculated on the assumption that the various rates—infection rate, recovery rate, death rate, etc.—are constants. It is, of course, realized that this simplifying assumption can only be regarded as approximately true. It renders the application of the general theory practicable, and the result of the investigation justifies its use, in so far as the theory so simplified does actually conform to the experimental results.

The statistical theory of virus determination by the dilution method is considered. It is shown that an algebraical method gives a solution which is rather more reliable than that given by the graphical method, and whose standard error may be calculated.

A sensitive antigen suspension is described for use with a simple slide agglutination method which makes possible a serological diagnosis or exclusion of typhoid fever without recourse to a laboratory. The method has been tested on 414 sera sent to our laboratory; it detected all cases with a titre of 1: 80 or more, and most of those with a titre of 1: 40. The method was further tested on 130 clinically observed cases, in which it gave satisfactory results. The S. A. method gave a positive result with 98 out of 100 sera from patients with typhoid fever, whereas the classical Widal reaction gave a positive result with 68 of them only.

The intensity and rapidity of the slide agglutination reaction provide a rough measure of the titre of a serum. A quick and distinct agglutination indicates a titre of 1: 80 or more and is diagnostic of typhoid fever. A slow and indistinct result is obtained when the titre of the serum is about 1: 40. A negative test indicates with great probablity that a diagnosis of typhoid fever may be excluded.

We think the method succeeds because the nature of the suspension employed and the peculiar behaviour of slide agglutinations permit the detection of O agglutinins as well as H agglutinins.

1. The examination of 1100 sera by both the Wassermann reaction and the complement-fixation test with spirochaetes revealed a superior sensitivity of the latter reaction and practically equal specificity of the two tests.

2. Syphilitic serum contains two different antibodies: one reacting with the lipoid antigen of the Wassermann reaction, the other with a specific antigen in the spirochaete.

3. The spirochaetal antibody of syphilitic serum has a complex serological structure, corresponding to spirochaete strains of different antigenic make-up.

4. The existence of this antibody and its specific absorption by the homologous antigen can also be demonstrated by agglutination.

5. The difference between agglutinin titres found in normal and syphilitic sera is not pronounced enough to render this method satisfactory for the practical diagnosis of syphilis.

6. The spirochaete contains, apart from its specific antigen, the ubiquitous lipoid substance representing the Wassermann antigen.

7. A fraction was obtained from spirochaetes by Raistrick and Topley's method which in complement-fixation and precipitation tests reacted actively with spirochaete antisera from rabbits, but which so far failed to react with syphilitic sera.

This work was carried out with the aid of a grant from the Rockefeller Foundation. I wish to thank Prof. Golla, Director of the Central Pathological Laboratory, L.C.C. Mental Hospitals, who rendered this work possible, and Dr Arthur Davies, Director of the Devonport Laboratory, for the hospitality afforded me at his laboratory and for the patients’ sera used in this work. I am indebted to Prof. R. T. Hewlett for his revision of the manuscript, to Prof. Raistrick for advice in chemical matters, and to Dr Amies, of the Lister Institute, for his help with the Sharples centrifuge.

During an epidemic of Sonne dysentery in Tooting Bec Hospital of which the epidemiological aspects have been described by one of us (Buckle, 1938), and during a recurrence of this epidemic, a number of strains were isolated of the causal organism (140) and various bacilli which were somewhat similar in their cultural and biochemical behaviour. It was thought that a close bacteriological and serological examination of these might be useful in giving information about the constancy of behaviour of the Sonne group, the question of possible biochemical subgroups of Sonne bacilli (Bojlén. 1934), and the relationship of the dysenteroid organisms isolated to the true dysentery bacilli, their classification, and significance.

Eleven cases of Weil's disease in miners from the west of Scotland have been encountered in the years 1937 and 1938. Only five showed jaundice.

Ten cases of infection previous to this period have been determined by serological means. Eight were jaundiced.

Information pointing to the occurrence of about eighteen more cases has been obtained from the Lanark public health authorities and from patients' statements.

The occurence of leptospiral infection appears limited at the moment but is quite serious in certain areas.

All available evidence points to the infectious being due to one specific strain of Leptospira.

I should like to thank the Physicians and Surgeons of the Royal Infirmary for permission to obtain sera from miners in their wards, and in particular Prof. A. W. Harrington, Dr J. C. Middleton and Dr J. N. Cruickshank for clinical details of cases. In addition, I would express my indebtedness to Dr J. M. Lang, Medical Officer of Health, Lanark, for the opportunity to investigate suspected cases, past and present.

1. The most common cause of bacillary food infection in this area is the aertrycke bacillus which has been responsible for most of the sporadic and familial outbreaks of so-called food poisoning. It was also responsible for one, the largest, outbreak of this condition in Dundee during the period under consideration.

2. The other sporadic cases were caused by different members of the group of Salmonella organisms—stanley, potsdam, senftenberg, while two cases were possibly due to a micro-organism having somatic relationship with the aberdeen bacillus although not possessed to the “i” flagellar antigen. It is probable, therefore, that these less frequently encountered Salmonellas are of wide distribution.

3. Two extensive outbreaks of milk-borne bacillary food infection due to the dublin type of the gaertner bacillus are described. In both, the source of infection was determined and proved to be a cow which had indubitably suffered from a septicaemic infection due to that micro-organism.

These two dublin outbreaks are of special interest in view of the findings of Conybeare & Thornton (1938) concerning the presence of antibodies to this bacillus in the blood of bovines and its presence in dejecta of a cow which, in view of the absence of evidence of illness, could only be regarded as a “carrier”.

If there be an appreciable number of carriers among bovines such observations as those of Montgomery (1938) concerning sporadic infantile meningitis due to the dublin bacillus are comprehensible though, of course, no explanation can be offered concerning the peculiar tendency to invade the meninges exhibited by this particular Salmonella.

1. A study of the literature of East Africa on the incidence of plague in field rodents shows that in no single instance has evidence been offered to prove they have any relation to the disease.

2. Recent epizootics in field rats in Kenya are described.

3. The health of house and field rats is discussed, with an account of the work carried out on a septicaemic condition present in field rats.

4. The results of bacteriological examination of 2750 field rats and attempted transmission experiments with 1285 field fleas, both investigations conducted during a period when there was heavy mortality among them, failed to establish the presence of B. pestis.

At the same time, mortality among the Rattus population, proved bacteriologically to have been caused by B. pestis, enabled successful transmissions to be accomplished with fleas from that species.

5. In the absence of any confirmatory bacteriological evidence to prove that epizootics among field rats are caused by B. pestis, and the failure to find natural infection among field fleas, together with the knowledge of their aversion to feed on man and lack of opportunity to develop such tastes, the theories that field rodents and their fleas “are definitely assisting in the perpetuation and spread of plague” or that they “ are possible factors in initial outbreaks of plague” (Thornton, 1930) appear to be fallacious.

6. Plague in Kenya is distinguished by its isolated and sporadic nature, even in endemic areas, and it is not dependent on types of housing or the general hygiene of inhabited areas, but on individual domestic habits. Any individual, neglectful in regard to food, particularly its storage and wastage, is the person responsible for the disease, by offering an unlimited supply of food to a dense rat population and encouraging its survival.