1. In the course of this investigation we have dealt with many cases of refection, but during a period of several years we never obtained the condition except when raw potato starch was the carbohydrate in the synthetic diet. Recently, in the exceptional circumstances described in the text, we have had a few cases with rice starch.

2. Like other authors, we have always found that in refected rats the caeca are always enlarged and their contents the seat of specially great bacterial activity. The nature of the dominant organisms present has varied from case to case, and in one it was apparently a yeast. Nevertheless, there is a suggestion that certain organisms are more potent in promoting refection than others. In rice starch refection, such organisms seem to be present.

3. We have found that the administration of roughage in the manner described can, to a large extent, prevent the establishment of refection. The number of organisms in the caeca is then greatly reduced and the contents indeed may become nearly sterile.

4. Using potato starch as the carbohydrate of the diet, we have had no difficulty in reproducing the results of the early experiments published by one of us (Hopkins, 1912), but we found that to obtain a growth induced by administering very small quantities of milk to vitamin-free diets, the presence of this starch is necessary. Indeed, the growth so promoted calls for the same particularity in the carbohydrate supply as does the establishment of refection.

5. Nevertheless, we have obtained what seems to be conclusive evidence showing that the growth with milk is wholly independent of refection.

6. We have obtained some evidence that potato starch contains growth factors in association with protein which only becomes soluble when liberated by treatment with pepsin HCl. As our experimental results bearing on this, for some reason at present unexplained, have lacked constancy, we can only claim, that they are suggestive.

1. Avian tubercle bacilli were cultivated in centri- fuged embryo extract in large hanging-drop preparations.

2. Small groups of individual bacilli were studied undisturbed on a warm stage for several days.

3. The cultures grew very actively and several types of reproduction were observed, all of which were modifications of what was arbitrarily termed the ‘standard’ type.

4. In the ‘standard’ life cycle, which was that most commonly seen, the bacillus elongates during the first 24 hr. to form a filament several times its original length; this divides repeatedly to form a bunch of 20–30 filaments which on the 2nd or 3rd day break down into short rods, which continue to multiply slowly by ordinary binary fission. If the bacilli are subcultivated in fresh embryo extract the cycle is repeated but not otherwise.

5. Three forms of slow growth were seen: (a) The bacillus elongates, though very slowly, to form a long filament which does not divide. (b) The bacillus elongates to about twice its original length and then divides by simple binary fission, (c) The bacillus elongates and segments into short rods, but the intermediate stage of filamentous proliferation is greatly restricted.

6. Bacilli floating freely in the surface film of the drop often form what we have termed a ‘raft’ colony. In this form of development elongation of the rods and filamentous proliferation occur, but the return to the original short form is gradual and incomplete. The organisms grow in one plane and are arranged in a tidy mosaic.

7. The development of ‘mycelial’ forms was studied. A minority of the long filaments formed by the elongation of the rod-shaped bacilli do not break up into strings of daughter rods but continue to elongate rapidly into abnormally long threads; small buds appear at intervals along the thread and grow into primary branches on which secondary and tertiary branches form in the same way: finally a complex branching ‘mycelium’ is produced.

8. The ‘standard’ life cycle appears to be characteristic of rapid initial growth. The wide differences between our results and those of Kahn are probably due, at least in part, to the different cultural conditions used in the two investigations.

1. An analysis of the complement-fixation reaction in influenza has been made by the use of chess-board experiments in which serial dilutions of antigen are tested against serial dilutions of serum with a constant dose of complement.

2. The reaction has been shown to be a complex one, involving two different antigens, the virus elementary body and the soluble antigen.

3. The soluble antigens of all strains of influenza virus A are identical, and different from the antigen of virus B.

4. The elementary body is a complex of several different antigens, and differences in antigenic structure can be detected between different strains of virus A. All elementary body preparations, however, contain soluble antigen which may be an intrinsic part of the elementary body or may be adsorbed.

5. The most suitable antigen for use in epidemiological studies is one containing chiefly soluble antigen, and a description is given of the method of preparation and use of such an antigen derived from infected mouse-lung tissue.

The author wishes to express his indebtedness to Dr C. H. Andrewes for some of the strains of influenza virus used in this work.

During the years 1943 and 1944 S. thompson, not hitherto reported in poultry in this country, has been isolated on forty-four occasions from thirty-one outbreaks in chicks, and two outbreaks in ducklings. Two extensive outbreaks are described in detail, and the epidemiology of the disease and its possible importance to public health are discussed.

We wish to record our appreciation of the help given by the late Dr R. B. Haines and by Miss E. M. L. Elliot, Ministry of Food, Department of Pathology, Cambridge, in the identification of some of the strains isolated from outbreak no. 1, and for the gift of a stock strain of S. thompson which was used in the typing of strains 2768 and 3845.

We also wish to thank Dr Joan Taylor, Emergency Public Health Laboratory, Oxford, for supplying us with factor 5 (absorbed) serum.

This paper embodies the findings in all proven cases of diphtheria admitted to the Hull City Hospital during the years 1938–43 inclusive. All cases during those 6 years were typed and the clinical and bacteriological findings correlated. Since 1932 all severe cases had been typed and in the winter of 1932–3 a consecutive series of 313 cases was investigated and the results published (Leete, McLeod & Morrison, 1933). The 1933 paper showed a high gravis incidence of 59% and an associated high case fatality rate. Not until the end of 1937 was it again possible to type every case admitted but since then we have done so, and the series now presented embodies observations on 2039 infections, the great majority of which were clinical cases.

In experiments at this Station designed to find the most appropriate methods for the dehydration of fish, it was early recognized that bacteriological control would be necessary in order to ensure the safety of the final product. Many preliminary experiments were performed before a suitable method was found for commercial production. In these experiments data were obtained and are given here to illustrate the general argument, although most of the results are concerned largely with the method finally adopted.

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.

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.