1. One hundred and seventeen rats have been examined, and thirty-two or 27·3% were found to harbour virulent Leptospira.

2. The correlation of carrier conditions with the presence of immune bodies in the serum showed:

(a) Leptospira-positive, sero-reaction negative, four or 3·4%.

(b) Leptospira-positive, sero-reaction positive, twenty-eight or 23·8%.

(c) Leptospira-negative, sero-reaction positive, twenty-one or 17·9%.

(d) Leptospira negative, sero-reaction negative, sixty-four or 54·7%.

3. The titres of the immune bodies in their sera have been determined. A positive reaction in the lower dilutions of the serum does not necessarily indicate that the rat is a carrier of virulent Leptospira.

4. There is evidence to show that there is a greater incidence of carriers amongst fully grown animals than in the young rodents.

5. Rodents which have been killed prior to examination in the laboratory are unsuitable for the determination of the presence of Leptospira.

Ice-Cream has occasionally been proved to be the carrier of disease, and therefore a study of the ingredients used, the processes of manufacture and the bacterial content of the final product is an important branch of modern hygiene.

1. Adequacy and balance in expenditure on the various items of food in the diet has been compared to the standard B.M.A. (1933) diet for a child aged 8–10 in eighty out of ninety-eight families with children attending four rural schools in Sussex.

2. The proportion that these items bear to the standard declines as the income is lower and the family larger. With the exception of bread, butter and cheese there is, in fact, a marked deterioration in the diet as the family grows, particularly in the lower groups. Bread, although declining, remains above the standard, with a few isolated exceptions, in all groups, and the proportion of cheese, although only about 60% of the amount recommended in the standard diet, remains roughly constant; butter and margarine fall below the standard only in the largest families. In contrast meat, eggs, fish, and milk, are reduced to considerably less than 50% of the standard in the larger families.

3. The balance of the diet is less defective but it is, nevertheless, profoundly influenced by growth of the family, especially where the income is small. The most marked alteration is the steadily increasing proportion of bread both as the income is lower and the family larger. In the largest families in all groups bread constitutes in the neighbourhood of one-third of the total expenditure. The tendency produced by reduction of income and increase of family to lessen the proportion of first-class protein in the diet (mainly by lessening the consumption of meat, eggs, and fish) is combated to some extent by an increasing provision of cheese, a more economical protein.

Discrepancies in coefficient values of the order of those recorded by the Laboratory of the Royal Institute of Public Health (1923) were obtained by the writer when determining the Rideal-Walker coefficient of four samples of disinectants. In these determinations he had adhered srictly to the technique laid down in the British Standards Institution's specification No. 541, of 1934.

1. Five hundred samples of sera sent for the Wassermann test were tested for the presence of H and O agglutinins for Bact. typhosum, Bact. paratyphosum A and Bact. paratyphosum B. Histories were obtained of nearly all those persons whose sera gave H agglutination at dilutions of 1:40 or higher, or O agglutination at 1:80 or higher. It was found that at least 20 people in this series had been inoculated or had suffered from enteric fever. The remaining 480 were considered to be normal. This assumption is likely to be correct in this community where typhoid is the only enteric fever which occurs, and that rarely, and where inoculation is not commonly practised.

2. The results are tabulated so as to show all the combinations of agglutinins which occurred at serum dilutions from 1:20 to 1:1280. Out of sixty-three possible combinations of agglutinins twenty-three were found to occur.

3. The interpretation of the results for single agglutinins and for certain combinations of agglutinins is discussed, and also the application of these results to the diagnosis of typhoid fever in this community and enteric fever elsewhere.

4. A comparison of the local “level” of normal agglutinins with that of other communities is made, and the origin of normal and co-agglutinins discussed.

1. A new technique is described for recovering applied organisms from the skin and other surfaces.

2. Experiments are analysed, in which staphylococci and streptococci are recovered by this technique from various areas of the skin and from glass and rubber.

3. It is concluded that the surfaces examined can be arranged in a definite order of decreasing disinfectant power.

4. The peculiar disinfectant power of rubber is considered.

5. The deterioration in surface viability of streptococci still surviving in saline suspension is described.

6. The experimental results are discussed in the light of previous investigations.

My grateful thanks are due to Professor J. B. Duguid, Department of Pathology and Bacteriology, Welsh National School of Medicine, Cardiff, for his patient counsel and criticism, and to Mr J. P. Napper, Technical Assistant for his skill in making apparatus and his help in the experimental work.

1. A technique for studying the behaviour of Salmonella in milk is described.

2. S. typhi, paratyphi B, dublin, cholerae-suis, typhi-murium, enteritidis and bovis-morbificans all multiplied readily even in absolutely fresh raw milk stored at 15°C., and in commercial grades of raw and of heat-treated milk rapid multiplication also occurred.

3. Strains of S. typhi recently isolated from man showed more rapid multiplication in milk than did stock laboratory cultures.

4. These Salmonella all survived at least 2 months when incorporated in various grades of salted and unsalted butter.

1. The diets of 120 pregnant women at different economic levels have been studied by the individual method.

2. The intake of calories was found to be little affected by income, and this was true also of fat and carbohydrate. The intakes of protein, animal protein, calcium, phosphorus, iron and vitamin B1 rose convincingly with income.

3. These differences were due to the fact that a rise in spending power led to an increased consumption of milk, fruit, vegetables and meat, and to a decreased consumption of bread and total cereals. Details are given in Table V.

4. Women taking the better diets were found on average to be taller and less anaemic than those taking the poorer diets. The differences were significant.

5. A comparison of the diets of the well-to-do women with the requirements suggested by the League of Nations and other authorities suggests that the requirement for calories has been set too high. The intake of calcium was suboptimal throughout and the diets of the poorer women were deficient in many respects.

1. Feeding tests on monkeys (Macacus rhesus), dogs and cats are unsatisfactory for detecting the presence of enterotoxin, owing to the variable susceptibility of these animals by the oral route.

2. Using Dolman's method, in which the material is injected intra-peritoneally into kittens, the production of enterotoxin has been demonstrated by: (a) sixteen out of thirty-eight strains of Staph. aureus, isolated from cases of acute or chronic mastitis or from normal udder milk; (b) four out of five strains of Bact. coli, mostly from calves with “white scours”. No enterotoxin was obtained from fifteen strains of Str. agalactiae from mastitis in cows.

3. The formation of enterotoxin under natural conditions has been observed: (a) In udder milk seeded with Staph. aureus or naturally contaminated with that organism and stored at atmospheric temperatures (18 and 22°C.). The substance remains active in cheese prepared from such milk. (b) In layer cake made with cream naturally contaminated with Staph. aureus.

4. A small outbreak of poisoning due to potted meat paste was shown to be caused by a non-haemolytic Staphylococcus.

5. A few feeding experiments on man with milk or cream, in which food-poisoning staphylococci had grown, were negative, but on one occasion a Staphylococcus from a case of mastitis yielded a culture filtrate which caused symptoms of food poisoning.

6. Enterotoxin has the following properties. It is resistant to heat (95°C., 30 min.), to low concentrations of formalin sufficient to destroy the haemolytic toxin, to acid (pH 5·0), and to rennet, but is destroyed by trypsin.

It diffuses freely into the culture medium but only slightly through collodion. It is antigenic. Its properties are such that enterotoxin can be classed as a bacterial exotoxin.

One of us (S. L. C.), with C. Weatherall and E. T. Waters, published in 1931 the results of some experiments on the adsorption of the active principle of tuberculin by the dust of anthracite coal and showed that the activity of a diluted tuberculin was greatly diminished after contact with pulverized anthracite. In view of this fact, we made the suggestion that some such adsorbent action of autotuberculin by the finely divided coal-dust retained in the lung tissues of silico-anthracotic coal-miners might, perhaps, explain the relative freedom of these latter from the progressive pulmonary tuberculosis so commonly noted as a sequel to silicosis in gold-miners and others exposed to silicious dust free from admixture with coal-dust. These experiments have since been repeated by us with similar results and we, therefore, planned to try out the adsorption effects of other dusts liable to be inhaled in the course of coal-mining in South Wales.