The experiments reported below followed the observation that living dysentery bacteria (S-variant) are not agglutinated after 4 hr. contact with an homologous antiserum. Somewhat later agglutination appears, but does not reach the end-titre. The next day fine granula are visible on the bottom of the test-tube which are readily dispersed by gentle shaking. This form of agglutination was designated ‘soft’. If the bacteria are heated for 30 min. at 100°C. agglutination appears within 2 hr. at all dilutions up to the end-titre of the serum. The next day a heavy sediment is visible, and in low serum dilutions a cuticula covers the bottom of the test-tubetities injected intravenously were 0·1, 0·25, 0·5 and 1·0 mg.; the latter were relatively harmless and quantities of 0·2–2·0 mg. were injected.

1. Details are given of further experiments on the disinfection of Bact. coli cultures by phenol using an improved standardized technique. These were carried out at several temperatures at each of five phenol concentrations.

2. An excess of high values of χ2 was again observed at high mortalities. Reasons for the occurrence of this phenomenon are discussed.

3. The logarithmic death-rates calculated between successive determinations of the surviving cells have been combined and analysed. Strong evidence was obtained that the death-rate rises to a maximum and then falls, sharply at first and then more slowly. There was some evidence for an initial rush in the death-rate.

4. The method hitherto adopted for treating these data, based on the assumption that the death-rate rises to a maximum at which it remains constant, has been shown to be a fair approximation but one which leads to low values for the v.s.t.'s.

5. Calculated estimates nearer to the true values for the v.s.t.'s have been obtained by treating the last phase of slow decline as one of constant death-rate. All values except those exceeding 1000 min. are increased by this change in method of calculation.

6. The new v.s.t.'s do not alter significantly the value previously obtained for the concentration exponent for phenol at 35°C.

The extensive epidemic of mumps which prevailed in Copenhagen in the winter of 1941–2 will presumably serve to establish whether Helge Petersen's (1941) general formula for epidemic curves for direct infectious diseases applies to mumps.

A high proportion of young men in this country suffer from premature baldness. Alopecia is not a disease entity but one of the outstanding features of chronic fluorine poisoning (fluorosis). It is frequently associated with dystrophies of other organs of ectodermal origin, namely, those of the skin and its other appendages, the teeth and nails. Since all these organs are regulated by the parathyroid glands, it is concluded that alopecia, too, is produced by fluorine acting through the medium of these endocrine glands. By its ability to precipitate the calcium content of the body, fluorine may lay the foundation for alopecia already in intra-uterine life, or produce it at any time after birth.

The action of fluorine is closely similar to that of thallium. There is ample evidence to show that in both fluorosis and chronic thallium poisoning the vegetative nervous system is vitally involved.

Toxic alopecia due. to fluorine is preventable.

The present inquiry was undertaken to obtain some indication of the relative frequencies of deaths amongst infants from the various forms of diarrhoea and enteritis—‘neonatal’, ‘parenteral’ and ‘infectious’—in the Greater London area in the decade before the war. Since much of the material needed for such an analysis was not available in the published records, a sampling inquiry, making use of the more elaborate records maintained by the Medical Officer of Health, was undertaken for the Borough of Willesden. A comparison of the relevant epidemiological and social conditions in this borough with those in the Greater London area as a whole showed, that for such a purpose, it might properly be regarded as a representative sample.

There was little evidence for the occurrence of the neonatal form in Willesden during the period studied, nor did the seasonal distribution of the deaths suggest that many took place in consequence of preceding parenteral infections. On the other hand, there did seem to be some evidence that a significant proportion of these deaths were in some degree associated with one another, in time or place or both, and it is suggested that this distribution might have resulted from the widespread dissemination in the community of one or more strains of some common micro-organism of relatively low virulence for all but the infant population.

A less detailed study of data for other London boroughs, viz., Bermondsey, Croydon, East Ham, Tottenham and West Ham, supported the main conclusion reached from the Willesden records.

1. Clinical examination of 374 industrial women workers and 289 housewives of comparable type was made in Oxfordshire in August 1942 and repeated four times subsequently on the same groups up to March 1944.

2. It was concluded that the diet of these women was adequate to prevent obvious signs of vitamin deficiency but that there was a general tendency for the general nutritional state, assessed clinically, to deteriorate during the 19 months of this study. This deterioration was associated with complaint of fatigue.

3. The women workers residing in areas where the water was low in iodine content tended to show enlargement of the thyroid gland. The enlargement increased in those already affected, and the incidence also increased.

The author is much indebted to Dr J. O. Irwin for his assistance in statistical presentation of the data and to Dr Harriette Chick for helpful criticism.

The bodies of pneumococci contain a constituent of protein origin which interferes with immunization.

This constituent can not only counteract the immunizing action of the species antigen, but reduce the immunity response to the type-specific antigen.

In heat-killed pneumococci (ordinary bacterial vaccine) the coagulation of the protein renders the anti-immunity factor relatively insoluble and minimizes its action.

In solutions of pneumococci the anti-immunity factor is liberated and reduces the immunity response to the type-specific antigen.

The immunizing effect of a small dose of heat-killed pneumococci can be abolished if the cocci be dissolved before injection. But a larger dose of dissolved vaccine produces immunity, the effect of the antigen predominating.

The anti-immunity factor is heat resistant at acid pH, but is destroyed by alkaline heat. In these respects it resembles the immunizing antigens.

The enormous increase in the number of children* eating their mid-day dinners at school canteens came at a time when enlargement of school buildings was impossible and when equipment was difficult to obtain. The following report on meals served in nine canteens illustrates the success that has been achieved in providing adequate meals in spite of great difficulties of preparation and service. The schools were chosen to represent different conditions of environment and type of canteen. Sample meals were analysed and an attempt was made to assess the home food of the children.

1. General considerations relating to the feeding of laboratory animals are discussed.

2. A cubed diet suitable for growing and stock rats and mice is described, together with wire-mesh, containers adapted to various types of cage.

3. The consumption and requirement of these cubes by growing rats and mice is recorded.

Enteric fever occurs in both temperate and tropical countries, and its spread depends mainly on the sanitary conditions prevailing, on the degree of purity of the drinking water, particularly in the country districts where no general water supplies exist, and on the degree of efficiency of the sewage disposal systems.

1. Fresh greenstuff is not necessary for rabbits, provided that drinking water is supplied.

2. A dry diet has been evolved which gives very satisfactory results with rabbits when supplemented only by hay and water.

3. Dry diet in the form of pellets is much more acceptable to rabbits than an identical diet in the form of meal.

4. The presence in the diet of 30% of even poorquality dried grass seems to supply an adequate amount of ascorbic acid, and the exogenous requirement of rabbits for this vitamin must therefore be very small.

5. Confirmation of the toxic effects of cod-liver oil for rabbits is given.

1. Iodine vapour at a readily tolerable concentration of 0·1 mg./cu.ft. of air gives a rapid kill of freshly sprayed salivary organisms at humidities above 50 %.

2. At the same concentration dry bacteria are not as readily killed, the killing rate only becoming appreciable above 70 % R.H.

Three major factors determine the tropical fitness of fabrics: (1) thermal insulation, (2) porosity, (3) reflecting power.

Growth of bacteria in an infusion of flax under quiescent conditions resulted in the formation of an acidic liquor with an appreciable content of volatile acids. When a similar infusion was aerated by a continuous current of air, the liquid tended to become alkaline and the content of volatile acids was much smaller and in some cases negligible. Aeration reduced the polluting strength of the liquor, as measured by oxygen absorbed from permanganate and by the biochemical oxygen demand, by much larger amounts than did growth under quiescent conditions.

Experiments with infusion in which the natural flora was allowed to grow, and with sterile infusion inoculated with pure strains of different types of bacteria, showed that the general effect of aeration was to alter the metabolism of the bacteria in the direction of more complete oxidation of the substrate. Balance sheets for carbon showed that the organic carbon lost from the culture was accounted for by the CO2 evolved. Thus carbohydrates, which under anaerobic conditions were fermented to organic acids, neutral volatile compounds, and gases, were oxidized, when the conditions were sufficiently aerobic; to CO2 and water.

The magnitude of the effects observed depended largely on the nature of the organisms present, and partly on the strength of the infusion in which they grew. With pure cultures of Bact. coli, Bact. aerogenes and Bacillus subtilis, and with the natural mixed flora of the flax, aeration at moderate rates in bottles for 3–5 days reduced the value for oxygen absorbed from permanganate by 43–52 %, and the biochemical oxygen demand by 26–92 %, indifferent experiments. The organic carbon content of the infusion was reduced by 30–31 % by Bact. aerogenes, by Bacillus subtilis and by the mixed flora. With streptococci and with a strain of Achromobacterium the effects observed were very small. Aeration at higher rates with diffused air in small open tanks reduced the organic carbon content of a flax infusion by 50 % in about 80 hr., and of a beetroot infusion by 50 % in about 60 hr. Sugar was destroyed during the aeration and disappeared rapidly from the flax infusion in the early stages.

The work described in this paper was carried out in connexion with an investigation of retting of flax and disposal of waste waters, made, as an extramural research, for the Ministry of Supply as part of the programme of the Water Pollution Research Board of the Department of Scientific and Industrial Research. The paper is published by permission of the Chief Scientific Officer, Ministry of Supply, and of the Department.