Certain sewage effluents have been found (Allen, Blezard, and Wheatland, 1946) to become highly toxic when treated with doses of chlorine much smaller than are required to give residual chlorine detectable by the ortho-tolidine test. Evidence from laboratory tests suggested that this toxicity was mainly due to a compound formed by interaction of the chlorine with small quantities of thiocyanate derived initially from gas liquor admitted to the sewage and surviving treatment at the sewage works. Key & Etheridge (1934) has shown that oxidation of the thiocyanate in a percolating filter or an activated-sludge plant, depends on the establishment of the necessary bacterial flora, and that a sudden increase in the concentration of thiocyanate in the sewage may result in a proportion of it being discharged in the effluent. Admission of gas liquor to sewage is common practice, and chlorination of such effluents would have serious effects on the living organisms, including fish, in surface waters to which they were discharged. Further work has revealed the nature of the compound responsible for toxicity, and has established the relation between toxicity and concentration of the substance in solution. An experimental study has been made of conditions affecting its formation during chlorination and of means of removing it from solution.

Opportunity was taken to study the morbidity of the more important groups of diseases affecting R.A.F. personnel with reference to the climatic conditions at Mingaladon, nr Rangoon, from February to July 1946. Temperature recordings (both wet and dry bulb), together with figures for humidity, were kindly provided by the Meteorological Forecast Centre at the station. The climatic conditions may be divided into two distinct periods: the pre-monsoon from mid-February to mid-May, and the monsoon itself which followed and continued throughout June and July.

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.

1. Investigations have been carried out on the bacteriophage method of typing staphylococci developed by Wilson & Atkinson (1945).

2. Strains previously considered as belonging to one phage type, type 42D, or as untypeable, were classified into a number of types by the use of additional phages. This further classification was rendered possible by the acquired phage resistance of some of the strains. All the resistant strains were lysogenic.

3. It was possible to produce a resistant variant of a strain to two phages. Some of these resistant variants carried both phages. Others could be demonstrated to be carrying only one phage.

1. The fat metabolism of three healthy European adult males has been followed for periods lasting from 7 to 22 consecutive weeks; a fourth subject was observed for a much shorter period. During this time the subjects consumed: A, their usual diet; B, a diet including 1 lb. of standard bread, made from 95 to 100% extraction flour; C, a diet including 1 lb. white bread, made from 70% extraction flour; and D, their usual diet. During the usual diet periods A and D, standard bread was also eaten. While each subject consumed the type and amount of fat he was accustomed to, his variations in intake, especially during the experimental diet periods B and C, were small. The intakes of the four subjects ranged from 55 to 115 g. daily.

2. The average absorption of fat during the usual diet periods was 94·0%; during the standard bread diet, it also averaged 94·0%; during the white bread diet, it averaged 94·9%.

3. It is concluded that with daily fat intakes of the order used in this investigation, a diet rich in whole-grain bread when compared with one rich in white bread does not lead to any appreciable diminution in the amount of fat absorbed.

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?

1. Investigations have been carried out on the bacteriophage method of typing staphylococci developed by Wilson & Atkinson (1945).

2. Acquired phage resistance has been shown to be responsible for the classification of many strains as different phage types.

3. Repeated testing of the same strains showed that the phage types were stable in character when the strains were maintained under laboratory conditions.

4. When two strains of staphylococci, one of which was lysogenic to the other, were grown together in broth, the susceptible strain underwent a change in phage type. As a result of this, it is considered that, in epidemiological studies, infective material should be plated directly on to a solid medium and not incubated first in broth, as is sometimes done. Evidence has been obtained suggesting that this change of type may also take place in the field. This phenomenon may be of some significance in epidemiological studies extending over a long period of time.

5. An attempt has been made to classify staphylococcal strains by phage methods into types that differ other than by virtue of acquired phage resistance. These are called, for convenience, genetic types. Reasons are given for the view that this may not be a satisfactory method of classification in practice.

1. The application of factorial design to. the testing of diets for breeding mice is described.

2. The use of a system of monogamous making, by which the females have a continuous series of pregnancies with concurrent gestation and lactation, is advocated for such tests.

3. Present indications are that a high wheat content or a high yeast content is desirable in the diet of breeding mice.

4. A diet containing a considerable proportion of full-cream milk was very effective for breeding mice, but it is not yet certain that this constituent is necessary.

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.

1. An analysis is made of 238 total calorie, protein, fat and carbohydrate intakes during wartime. These represent the 24 hr. mean of 48 hr. investigations carried out at six-weekly intervals throughout pregnancy on 55 healthy working-class women on self-selected diets. These investigations were carried out from April 1943 to the end of 1946. Throughout this period, ‘wartime’ rationing conditions prevailed.

2. The total calorie intake is analysed. 49·8% of the series in the ‘first half’ of pregnancy and 46·9 % in the ‘second half’ of pregnancy were found to be suboptimal according to recognized standards.

3. The protein intake is analysed in terms of (a) total intake, and (b) g./kg. body-weight. The latter analysis showed that 33 % of the figures in the ‘first half’ of pregnancy and 46 % of the figures in the ‘second half’ of pregnancy were sub-optimal.

4. The percentage of animal protein is contrasted with that of vegetable protein; a satisfactory animal protein percentage is found. The latter is derived partly from the extra pint of milk and partly from adequate quantities of meat, offal and fish. Over 40 % of the women ingested no cheese at all. The remainder consumed relatively small quantities.

5. The total fat intake is analysed. Over 50 % showed a fat ingestion of more than 100 g./day.

6. The total carbohydrate intake is analysed and the average ingestion found to be below 300 g. An analysis of the amounts of bread eaten per day showed a large proportion of intakes below ½ lb. (225 g.) per day—76 % in the ‘first half’ and 75 % in the ‘second half’ of pregnancy. The potato intake was relatively higher. The mean daily consumption was 191 g. with a maximum of 435 g. A list is also given of the amounts of the other common farinaceous foods consumed.

7. An analysis is made of the percentage of total calories accounted for by protein, fat and carbohydrates respectively. When the figures are compared with the accepted standards of 15 % protein, 35 % fat and 50% carbohydrates, the findings are (a) a slight preponderance of low protein intakes, (b) a preponderance of high fat intakes, and (c) a preponderance of low carbohydrate intakes.

8. The figures for all three constituents—protein, fat and carbohydrate—compare favourably with those given in prewar surveys of nutrition in pregnant working-class women.

An individual dietary survey of 111 primiparae was carried out in Bristol during 1947. Compared with a group studied by McCance in 1938, these women were getting twice as much milk, more bread, potatoes, vegetables and fish; they were getting less meat, butter and margarine. 84 % were taking supplements of vitamins A and D.

Compared with the N.R.C. standard for pregnant women the diets were very poor, not one reaching the standard. It is felt that the N.R.C. standard for pregnant women is set too high. Compared with the standard for sedentary women there were deficiencies in vitamins B and C, the most marked being in nicotinic acid (74% of diets). As a group they appeared to be well nourished, only 8 % had a Hb below 80% and only one a plasma protein below 5·5 g./100 c.c.; there were no stigmata usually attributable to nutritional deficiencies. The only complication of note was toxaemia, which occurred in 15% of cases. The only deficiency in the diet common to all cases of toxaemia was in nicotinic acid. The mean intake of nicotinic acid was 2·0 mg. lower in the toxaemic group than the mean intake of nicotinic acid in the normal subjects. This difference was statistically significant. Evidence is presented which suggests that deficiency of nicotinic acid or vitamin B6 may be a predisposing factor in the production of toxaemia of pregnancy. The main cause of defective nutrition appears to be ignorance and not lack of money, this is an additional reason for the promotion of an intensive nutritional education programme.

The appointment of dietitians to ante-natal clinics is stressed as an important step in promoting education in nutritional matters during pregnancy.

The use and abuse of recommended allowances in pregnancy is discussed and the following diet is suggested as a reasonable practical allowance for pregnant women: calories, 2500; protein, 1·5 g. per kg. body weight; calcium, 1·5 g.; iron, 15 mg.; vitamin A, 3500 units (pre-formed); vitamin D, 800 units; vitamin B1; 1·5 mg.; riboflavin, 2·0 mg.; nicotinic acid, 14 mg.; vitamin C, 50 mg.

1. A description is given of active forms and cysts of an amoeba found in wild London rats, and morphologically identical with E. histolytica.

2. When inoculated into the caeca of young rats, the amoebae invade the wall and produce lesions.

3. Acute infections produced in experimental rats respond to treatment with emetine hydrochloride.

4. The naturally infected rats were restricted to a localized focus, in which cases of human amoebiasis were discovered, thus providing circumstantial evidence of the human origin of the infection, and throwing light on the possible role of rats as reservoir hosts.

Bacillus dysenteriae Flexner (Shigella paradysentriae) grown on Lemco agar plates (without peptone) containing sulphanilamide 1/20,000 to 1/10,000 forms papillae which on subculture yield two strains: (1) the original strain unmodified and (2) a strain resistant to SA.

The latter has arisen by discontinuous variation. There are no forms intermediate between strain (1) and strain (2).

In one such case (Exp. 1, p. 334) the no-contact race, the unmodified non-resistant strain from the primary sulphanilamide plate and the resisting variant strain were titrated in broth containing sulphanilamide in ten increasing concentrations from 1/34,000 to 1/5000. The first two strains, the no-contact and the unmodified non-resistant from the sulphanilamide plate grew in SA 1/34,000 and failed in 1/21,000, while the resisting variant grew up to the tube containing SA 1/6000 and failed to grow in 1/5000.

On plates containing sulphanilamide this adaptive variation takes place only in the papillae. It can also take place in broth containing, for example, SA 1/20,000 to 1/10,000.

There is no such thing as gradual progressive acquisition of resistance by the whole of a bacterial population exposed to a drug. Such phrases as ‘teaching bacteria to resist’ are misleading and anthropomorphic and should not be employed.

Fluid cultures which show a progressive gradual increase of resistance do so as a result of an increasing percentage of resistant cells in a mixed population of resistant and non-resistant bacteria. Experiments in fluid media should always be checked and the growth analysed by plating.

Resistant strains maintain this character after prolonged growth on drug-free media.

(2) Flexner's dysentery bacillus grown on plates containing acriflavine 1/60,000 to 1/40,000 forms in papillae strains resistant to this drug. The non-papillary areas of colonies die early, viz. on the 3rd day. The variation in this case also is discontinuous.

(3) On the other hand, if Flexner's bacillus is grown on agar containing organic compounds of silver or arsenic (argyrol or neosalvarsan), it forms no variants resisting these drugs.

(4) Papillae possess two biological functions: (a) they are the site of adaptive variation in response to elements in their environment, such as harmful drugs or useful sugars; (6) they are also the site of rejuvenation of senile cells and of cells affected by common unfavourable conditions such as exhaustion of food supply and accummulation, of excretory substances.

The greatest development of papillae takes place on plates which form no variants, such as plates of drug-free agar, agar plates containing sulphanilamide sown with strains resistant to sulphanilamide and plates containing organic compounds of silver or arsenic.

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.

Gaseous insecticides, such as methyl bromide and methallyl chloride, are being used on an increasing scale against insects attacking stored products such as grain, tobacco, etc. Their use involves two possible dangers. In the first place, the worker may be poisoned either during the actual gassing operation or during the preparatory period. Secondly, there is the possible danger to consumers through the absorption of these furnigants into the stored product.

1. Bacteriological examination of large samples of Perch and Powan from natural and artificial waters has shown that a considerable decline in the normal bacterial flora of the fish occurs during the summer months. Reinfection occurs when the temperature falls.

2. These variations are largely attributable to the effect of temperature upon the immunological responses of the fish.

3. The bacteria concerned appear to be water bacteria, which invade the muscles and body cavity of the fish, as well as the gill and gut-content.

4. The degree of infection is also influenced by the bacterial content of the water.

1. Evidence is given that in recently inoculated persons the Widal reaction, even when serial quantitative tests are done, has no practical value in the diagnosis of enteric fever. Conscription enlarges permanently the inoculated proportion of the whole population.

2. The diagnostic value of any particular titre depends not only on the relative frequencies with which this titre occurs in normal and infected individuals but also on the incidence of enteric fever in the population and on the fashionableness of the Widal test as a diagnostic aid.

3. It is emphasized that blood culture is a more reliable aid to diagnosis than the Widal test.

1. Of 1552 strains of Staph. pyogenes tested by the slide-agglutination technique, using the absorbed and unabsorbed sera suggested by Cowan, 74% of strains were identified while 26% remained untyped. Of untyped strains, half were inagglutinable while the remainder gave ‘indefinite’ results and remained unclassified. The introduction of two new sera, used diluted but unabsorbed, considerably reduced the number of untyped organisms but made little difference to the proportion of ‘indefinite’ strains. The method was simple and quick, but the variety of cross-reactions often prevented a clearcut differentiation of strains and the number of types identifiable was limited.

2. Of three methods of agglutination, titrations on glass slides were preferred because by this technique end-points were clearer than those obtained in a water-bath or by the method for determination of Vi antibody.

3. Agglutination of seventeen strains of Staph. pyogenes with homologous and heterologous sera showed that the use of unabsorbed sera was of limited value for typing because of the marked cross-reactions.

4. Christie & Keogh's division of Staph. pyogenes into nine types was promising but their absorbing methods allowed much antigenic overlap.

5. Experiments with absorbed sera showed that no single strain of Staph. pyogenes could be used successfully to absorb all sera. There appeared to be groups or pairs of types in which serologically the individual members resembled each other very closely and yet were not identical. In these instances the absorption of a serum by a heterologous strain nearly related to the homologous strain proved of most value in the preparation of specific sera.

6. A set of seventeen absorbed sera was prepared from Cowan's three types of Staph. pyogenes, from six of Christie & Keogh's type strains and from eight additional strains freshly isolated from staphylococcal lesions. With some absorbed sera there was specific agglutination with the homologous strain and no heterologous reactions, other sera reacted with several strains and could not be made specific.

7. Seven specific serological types were recognized while a further eight types showed less specific reactions and were identifiable by a pattern of reactions. A number of strains differed slightly one from another in their agglutination reactions, and it was not possible to decide whether these were additional types or variants within types.

8. In a small series of experiments the precipitin reaction, using unabsorbed sera, seemed of little value in the differentiation of strains of Staph. pyogenes.

9. Of 259 coagulase-positive strains examined during 1946 and 1947, all were identified by agglutination reactions, although they varied in their specificity; 67.5% of these strains were identified by staphylococcal bacteriophage reactions.

10. A preliminary comparison of serological and bacteriophage types showed a fairly regular but not complete correlation between the results obtained by the two methods. A number of serological types were regularly lysed by the same bacteriophage filtrates; a few were consistently untypable by phage indicating that filtrates had not as yet been found for them or that the strains were phage resistant.

Others which were not clear-cut in their reactions and which were recognized by patterns of reactions with both sera and phage filtrates did not always show a close correlation in the typing results.

11. The application of both serological and bacteriophage typing to the investigation of outbreaks of staphylococcal infection has proved to be of value in tracing sources and paths of spread of infection. In several instances the use of both methods of typing has led to conclusions which would not have been warranted if one method alone had been used.

Methods have been described by which capsules and mucoid envelopes of bacteria can be fixed and stained positively and differentially, proving they are of different natures. The capsule is of definite shape and outline, the slime is amorphous. Some bacteria may have capsules, some may produce slime, and in others the capsulated organisms may be embedded in amorphous slime, as, for example, in the Fried-lander bacillus and in the Pneumococcus, type III. These properties are probably more or less characteristic for certain organisms or groups of organisms. Of course, loss of capsules, and loss of slime production do occur.

All bacteria which have capsules seem to possess special antigens (cp. Kauffmann's A-antigen). This was particularly shown for members of the coli-oerosrenes-Friedlander groups and Streptococcus para-faecalis (Skadhauge). Organisms with L-antigens possess generally no capsular or mucoid envelopes of the type described, with one exception, viz. strain Bi 316/42.

By means of the capsule- and slime-staining methods here described, a densely staining edge was demonstrated in the bacteria examined, which—it is suggested—may comprise the cell wall and its adjoining cytoplasmic layer. Organisms supposed to have no cell walls (Myxococci) do not show this appearance.

The so-called ‘swelling reaction’ is a reaction between antiserum and homologous bacteria, by which the capsule becomes easily demonstrable. It seems doubtful that actual swelling takes place.