Before the war diphtheria, measles, tuberculosis and whooping cough were the most important of the better-defined causes of death amongst young children in the London area. The large numbers of deaths registered from these four diseases in the age group 0–4 years in the Metropolitan Boroughs alone between 1931 and 1938, together with the deaths recorded under bronchitis and pneumonia, are set out in Table 1.

Investigations at two hospitals, P and S, showed Staphylococcus aureus to be commonly present in the milk of healthy nursing mothers and the throat and intestine of their babies. In hospital P, the proportion affected in a group of eighty-two mothers and their babies was over 90%. The condition may not be uncommon in maternity hospitals, but no information of its occurrence is available from private obstetrical practice. The cocci concerned seemed to be of low virulence, for babies swallowing relatively massive doses in their mothers' milk suffered no perceptible ill effect. On the other hand, the coccus was found in the pus of the only case of breast abscess encountered, and in some minor external pustular lesions. It was present in the milk of all the cases of flushed breast examined, but its causal connexion with this condition awaits proof.

The staphylococci, in the majority of cases, seemed to occur first in the baby's throat, possibly from a focus of infection in the babies' ward, and to be transmitted from baby to baby and from baby to mother, with a return infection, in larger amount, through the mother's milk. The mother's nose and throat must be included amongst other, but less frequent, sources of the infection.

The predominating type of Staph. aureus gave a relatively strong coagulase reaction which was caused only by actively growing cocci, but it would seem that the reaction caused by this agency is less trustworthy as an index of virulence of the coccus than one in which free coagulase also operates.

The new data presented show that the life cycle of the L1 organism separated from cultures of Streptobacillus moniliformis corresponds in many respects to that of pleuropneumonia. It seems therefore justifiable to classify it with the group of pleuropneumonia-like organisms and not with the bacteria. Its peculiar life cycle, including the formation of elementary reproductive corpuscles, a process previously described for pleuropneumonia, but not occurring in bacteria, is regarded as strong evidence in favour of the conception that Str. moniliformis is composed of two genetically different microbes, a Streptobacillus and the LI organism. Cross-absorption tests between Str. moniliformis and the LI organism have shown that these organisms possess different serological affinities.

Owing to the entry of Japan into the war it is essential that agar should be used as economically as possible. Since October 1941, we have, in this laboratory, reclaimed used agar by the following simple method, which is a modification of the procedure described by Huang, Shen & Tang (1941).

There is a close similarity between the dental changes produced experimentally in the rat by parathyroidectomy and mottled teeth as seen in man and known to be caused by protracted ingestion of toxic amounts of fluorine. In view of the fact that both parathyroidectomy and fluorine produce dystrophies in tissues regulated by the parathyroid glands it is concluded that, in man, mottled teeth, certain dermatoses, mottled nails and alopecia may be due to a disturbance of these glands brought about by the ingestion of toxic amounts of fluorine in drinking water.

1. Between September 1941 and January 1942 haemoglobin estimations were made by the Haldane method on 544 women and 530 children, aDd the values obtained compared with those for similar groups investigated before the war. 2. The women investigated were grouped as follows: (a) 353 nurses and students at a London teaching hospital and its base in the country, (b) 159 workers at a factory in a small town near London, and (c) 32 housewives, mothers of children attending a hospital in the East End of London. 3. The mean haemoglobin value of the 544 women was 89·5 % and the range was from 56 to 120%. The mean is very similar to that obtained by Davidson et al. in 1937 for a group of nulliparous women from the poorest class in Aberdeen. In contrast Price-Jones's (1931) mean figure of 98·3% for 100 supposedly healthy nurses and women students, and Jenkins & Don's (1933) mean figure of 100·5% for 116 women are significantly higher than the mean of the present series. The percentage haemoglobin was below 90 in 54 %, and below 80 in 10 % of our cases. In Price-Jones's series no haemoglobin value was below 90 %, though in Jenkins and Don's series it was below 90 in 9 % and below 80 in 1 % of the cases. 4. The mean haemoglobin value of all the nurses and students was 87·2 %. The mean for those working in London was 90.6 % and for those working in the country was 84·1 %: the difference between these means is significant. The mean values of the nurses and students working at the same hospital approximated closely, as did the mean value for the auxiliary nurses to that of the professional nurses at the same hospital. 5. The mode of life and conditions of work in the two hospitals did not differ materially. A comparison of the diets of the nurses at the two hospitals showed that in London, over a period of 3 months, the average daily intake yielded 1865 calories and 63·5 g. of protein, of which 41 g. were first-class protein; whereas in the country, for the same period, the diet yielded 1662 calories daily and 46·7 g. of protein, of which 28 g. were first-class protein. It was estimated that the London group had a daily iron intake of 10.8 mg. and the country group one of 9·2 mg. 6. The mean haemoglobin values of the factory workers and the London housewives were 94·0 and 89·6% respectively. 7. A small number of nurses and students with low haemoglobin values had regular iron medication and the majority showed a satisfactory response to treatment. 8. There were in the present, series 364 children aged 6 months to 5 years. They were examined at welfare centres, diphtheria immunization clinics and day-and residentialnurseries. The curve of their mean haemoglobin values at successive ages approximates to corresponding curves of 10 years ago for British children not receiving medicinal iron. In our present series the average haemoglobin level at 6–12 months was 75·4%. Between 1 and 2 years of age the level had dropped to 72·8%, and thereafter it gradually rose, reaching 81·8% between 4 and 5 years of age. The lowest levels were found in children under 2 years of age. Since iron treatment of such infants will not only raise their mean haemoglobin level, but also halve their morbidity rate (Mackay & Goodfellow, 1931), the haemoglobin level of these untreated babies must be considered pathologically low. The incidence of severe anaemia was lower in the welfare group than in the other groups and was highest among the children in the residential nurseries. 9. The mean haemoglobin level of 90 school children aged 5–13 years was 80·3% (about 10% lower than Davidson's (1935) mean for poor children in Aberdeen), of 38 school children aged 13–15 years 89·3% and of 38 adolescent girls working at the factory already mentioned 98·7 %. 10. In all the groups of women and older children, with the exception of the small group of girls working in a factory, the mean haemoglobin values were significantly lower than those of previous groups with which we could compare them. We believe that this general lowering of the mean haemoglobin values of the older subjects and the low curves obtained for the younger children are the expression of a nutritional anaemia. We also believe that iron deficiency is one important aetiological factor, but that other factors have also played a part in the production of this anaemia. It is probable that among women and school children other dietetic deficiencies are implicated, and that in nurseries a high incidence of infection has increased the incidence and severity of an anaemia primarily due to an iron deficiency. 11. We believe that the bearing of this anaemia on the health of the nation is of sufficient importance to call both for official action at the present time, and for further investigation.

Wells (1937) discovered that field voles in this country are subject to an epizootic disease due to an acid-fast bacillus. The natural disease in the vole is characterized by the deposition of a cheesy substance in the areolar tissue spaces and the formation in the organs, the lungs particularly, of lesions which have a close resemblance to those of tuberculosis.

From pneumococci a species antigen can be obtained which on injection gives protection against pneumococci of different types.

Species antigen is a somatic constituent of pneumococci and can be obtained in solution free of protein. It may be of carbohydrate nature, but is not derived from the type-specific material.

The bodies of pneumococci contain another substance which on injection opposes species immunization. This opposition factor is closely associated with the protein content.

Inconstant results from injection of preparations containing species antigen are due to the presence of opposition factor in varying amount.

A high degree of species immunity can be secured by the use of species antigen freed from opposition factor.

Salmonella strains isolated in Palestine from camels could not be differentiated from a human strain isolated in the same country. The Palestine strains differ from S. kentucky by lower fermenting activities, but are antigenically identical with it.

At the beginning of the war, the London County Counoil issued a report by Sir Frederick Menzies, their late School Medical Officer, on the average heights and weights of London elementary school children in 1938. The report is based on the measurements of about 100,000 children, and is probably the most important contribution to the anthropometry of childhood that has appeared in this country for many years.

1. The six ‘viruses’, Liverpool, Danysz, London, Ready Rat Relief, Institut Pasteur and Ratin, which are the principal bacterial cultures at present employed for anti-rodent control in Great Britain, have been examined. 2. By means of reciprocal absorption tests all these six strains were found to be serologically identical with S. enteritidis Gaertner, antigenic structure, IX:gom:—. 3. From the results of the fermentation tests, which may be used to subdivide this serological type, Liverpool, Danysz, Ready Rat Relief and Ratin were assigned to the var. danysz subgroup; while the London and Institut Pasteur strains could not be distinguished from the classic S. enteritidis type. 4. Both of these subgroups are pathogenic for man, and evidence is cited which shows quite clearly that human cases of gastro-enteritis have been caused by the use of virus preparations. There are, also, reasonable grounds for believing that these bacterial types may be pathogenic for a number of domestic animals, including some poultry.