1. The field epidemiology is described of two epidemics of smallpox which occurred in Tripolitania during 1946.

2. Control was effected by the ‘expanding ring’ method instead of mass vaccination of the population.

3. Five hundred cases were admitted to hospital and statistics are given of mortality in relation to age, sex and vaccination state.

4. A new clinical classification is described which enables a reliable prognosis to be made and provides a guide to treatment.

5. Controlled experiments were made on the use of penicillin in treatment. Although it is without effect on the viraemia and in general does not significantly affect mortality, it has the power of suppressing suppuration and reducing the effect of secondary sepsis. It also minimizes the amount of permanent scarring of the skin.

6. Evidence is presented to show that the period of maximum infectivity is the stage of the pre-eruptive fever. The mildest cases are infectious, but only for a short time.

The virus contained in dried scabs is not considered to be an important source of infection; it may, be modified in some way by passage through the skin.

7. Although not protected by successful vaccination many contacts showed a considerable resistance to infection. Amongst the older people this may have been due to previous clinical or subclinical attacks. Amongst the younger persons evidence is produced to show that many were relatively refractory to vaccination and experienced the disease in a different way, suggesting that there is natural partial immunity to smallpox in this particular population.

8. The complex problem of immunity in smallpox is discussed, and it is suggested that three factors operate, an anti-invasion factor, an anti-dissemination factor and a local skin immunity mechanism. A photograph is given of a model made to show the interaction of these three factors in producing the immunity levels which determine the type of disease. It also accounts for the immunity reactions in vaccinia and in smallpox in the vaccinated subject, both when vaccinated successfully during the incubation period of smallpox and when vaccinated successfully some time prior to contact.

It was perhaps unfortunate that this work had to be done under Service conditions without access to literature such as Ricketts & Byles's (1908) classic The Diagnosis of Smallpox, or Marsden's works, particularly his review of vaccination (1946). The lack of authoritative guidance, however, was compensated for by the enthusiasm of all concerned.

I am especially grateful to Lt.-Col. W. McN. Graves-Morris, R.A.M.C., P.M.O. Tripolitania, for allowing me the opportunity to experiment and to use such a large proportion of the territory's supply of penicillin.

I am indebted to Col. W. W. Sharpe, R.A.M.C., D.D.H., M.E.L.F., for enabling me to return to Tripolitania for a short time to complete the records, and to Capt. J. Macbeth, R.A.M.C., Capt. W. L. Forbes, R.A.M.C., Capt. J. Anderson, R.A.M.C. and the late Capt. J. LaFerla, R.A.M.C, who assisted at different stages and in different ways.

1. Elementary body suspensions of vaccinia and ectromelia were obtained from rabbit skin and chick embryo or mouse liver and chick embryo respectively and used to immunize rabbits.

2. Judged by the complement fixation and haemagglutination tests, the viruses from different hósts were very similar antigenically. Ectromelia and vaccinia appeared closely related, the heterologous virus titres being usually lower than the homologous.

3. Elementary body suspension agglutination tests did not reveal a similar relationship between the two viruses, but were not satisfactory on account of the low antibody content of the antiectromelia sera.

4. Highly active ectromelia antisera were not obtained and there was no evidence of multiplication of this virus in rabbits.

5. Only slight neutralizing activity was demonstrated in the antisera.

6. Elementary body suspensions of ectromelia virus prepared from mouse livers, as well as the crude liver extracts, were soon inactivated. Egg membrane preparations were relatively stable.

1. Two long-continued epidemics of mousepox were set up with different strains of the virus and maintained for 190 and 290 days respectively. Considerable differences were observed between the behaviour of the two strains of virus, the Moscow strain being much more virulent and more highly infective than the Hampstead strain.

2. The two strains of virus maintained their original characters through the experiments.

3. Life tables were constructed for both epidemics, specific and non-specific deaths being dealt with separately. They show that high and durable immunity follows recovery from infection.

4. Two mice which had recovered from infection were found to harbour small quantities of the virus in the lungs, and in one case in the spleen also, suggesting that chronic latent carriers of the virus may occur.

Quantitative studies have been made of the survival of foot-and-mouth disease virus in beef and beef offals after storage at temperatures employed in the imported-meat trade.

The survival of virus is closely associated with the hydrogen-ion concentration of the tissue; thus the acidity of rigor mortis of muscular tissue rapidly causes inactivation. Quick-freezing of beef suspends acid formation and active virus was demonstrated for so long as the meat was kept frozen.

Thawing of quick-frozen meat initiates the suspended acid formation at an accelerated rate and rapidly produces a medium unsuitable for virus survival.

Liver, kidney, rumen, lymph node and blood from diseased cattle have all been shown to be highly infective and to remain so if stored frozen. Acid formation in these tissues and in blood is not on the same scale as in muscle, and prolonged survival of virus is more likely even with delay in freezing and after thawing. This remains true of lymph node and of residual blood in vessels of a carcass in which the development of rigor mortis is complete.

Feeding of infective offal to swine under experimental conditions resulted in the appearance of the disease.

The significance of these observations is discussed in relation to the distribution of these products constituting a risk of spreading foot-and-mouth disease.

We are indebted to Dr Ian A. Galloway, Director of this Institute, Mr L. B. A. Grace, Chief Technical Adviser on Meat Inspection of the Ministry of Food and Mr R. Bremner, Chief Executive Officer of the Meat Importers' National (Defence) Association, Ltd., for their help and advice while this work was in progress.

It is a pleasure to acknowledge the technical assistance of Mr W. J. Brownsea.

1. Six cases of haemolytic disease in newborn foals apparently due to iso-immunization of pregnancy are described from their clinical, serological, haematological and pathological aspects. The findings agree closely with those seen in the same disease in newborn mules.

2. The disease may be diagnosed serologically by demonstrating the in vivo iso-sensitization of the foal's red cells by means of the direct antiglobulin-sensitization test. It is quite possible that after further investigation a modification of Diamond's albumin tube test may also be of value. Immune anti-red cell iso-antibodies of more than one specificity may be demonstrated in the dams' sera.

3. Despite the acute haemolytic process, very few reticulocytes and no erythroblasts are seen in the peripheral blood.

4. The morbid histology of the tissues of foals dying with the disease exhibits various points of interest which are discussed.

5. The clinical aspect is not described in this paper in any detail. However, a programme is suggested which would enable a successful exsanguino-transfusion of compatible blood to be carried out at very short notice. At present this seems to be the logical and most practical method of specific treatment.

1. Recovery of a strain of Brucella abortus Bang from a foetus aborted by a cow in Mauritius is reported.

2. Agglutination tests performed on samples of blood from cows of the Government Dairy indicate that contagious abortion of cattle is present in this country; approximately 24% of the animals from the Government Dairy belonged to the latent or past infection group; 18 % to the active infection group and 15% were presumptive bacilli excreters.

3. As aresult of agglutination tests with the blood serum from man Undulant fever due to Br. abortus is suspected to occur in Mauritius.

A description is given of a simple method of determining the sensitivity of bacteria to sulphonamides by means of impregnated blotting-paper disks applied to nutrient agar prepared from broth freed from sulphonamide antagonists by incubation with lysed horse red blood cells.

With organisms sensitive to the selected sulphonamide, a zone of inhibition of growth will occur, the diameter of which is related to the concentration of the sulphonamide necessary to inhibit growth. Sensitivity to several sulphonamides can be determined simultaneously.

The impregnated disks can be stored without loss of potency.

A colony count performed by spreading a known volume of suspension on the surface of a plate possesses certain advantages over other methods, of which the chief is ease of counting.

The distribution of counts of several samples of the same suspension on medium of the same age and batch is as expected on statistical grounds.

Different batches and ages of blood plates may give substantially the same count but this is not true for Leifson's and Wilson & Blair's media.

A diluting fluid, which is satisfactory if blood agar is the plating medium, may not necessarily be so if special media are to be used.

The use of fumigants against insects attacking stored products involves two possible dangers. In the first place workers may be poisoned by inhaling the fumigant either during its use or its manufacture. Secondly the fumigant may be adsorbed onto food-stuffs thereby hazarding the health of consumers.

Guinea-pigs are usually mated in permanent polygamous groups, one or more males with a large number of females, the young being harvested when ready to wean. This system is economical of labour, and is efficient in allowing of mating at post-partum oestrus and therefore of maximum reproductivity. There are, however, serious disadvantages; it is difficult to keep track of individual performance and difficult therefore to eliminate unproductive sows, the ancestry and exact age of the young are often unknown, and the conditions of rearing young among a crowd of adults are probably not ideal. These considerations suggest that, given high-grade breeding stock, the polygamous system is adequate, and probably inevitable, for the mass production of young for experimental purposes, but that it leaves much to be desired for the production of breeding stock. The obvious solution of this difficulty is to maintain a large polygamous and anonymous colony for mass breeding, and, quite separately, a small closely recorded colony to supply the breeding animals. A goodsow should produce at least 10 young per year in a life of 2 years. A demand of 10,000 animals per year, for experimental work, therefore requires a mass-breeding stock of 1000 sows, an annual replacement of 500 sows and a stock-breeding stock of 100 sows. According to our experience, about 2 hr. daily on the part of a trained technician would be required to maintain close recording of such a pilot stock and of its progeny to puberty (Bruce & Parkes, 1947b).

In December 1945, Lofgren & Soule described the structure of Spirochaeta novyi, as revealed by the electron microscope but, owing to the present emergency conditions, this work has only now come to our knowledge.

The recent inclusion of the diabetic child in the list of children for whom special provision is required to be made by Local Authorities confronts the School Medical Officer with the following questions:

(1) To what extent does the disease exist in a school population?

(2) Is it increasing, and if so, to what extent?

(3) What is its significance in terms of morbidity?

(4) What is its significance as a source of loss of child life?

(5) To what extent is the disease subject to control?

It is commonly believed that a concrete floor feels cold, whereas a wood floor feels warm. It is not clear however, under what conditions this statement is supposed to be valid, if, in fact, it is true at all. Nevertheless, one supposes that it applies certainly to walking barefoot across the floor; and it is believed by many to apply also when shoes are worn. In common usage, however, no attempt is made to eliminate the factor of surface temperature.

When complaints of cold feet are made in rooms with concrete floors, there is a tendency amongst people to attribute the discomfort directly to the concrete. It is, of course, obvious that to a bare foot concrete feels very much colder than a cork or wood surface; but it is not so apparent how a floor of comparatively high thermal conductivity such as concrete can appreciably affect the feelings of warmth when the feet are shod. Even the light footwear usually worn by women, being composed of more than one layer of material, must offer considerable resistance to heat loss. In addition, the area of the sole of the shoe in actual contact with the floor is small.