The agglutination of red cells of seventeen animal species by influenza and Newcastle disease viruses has been quantitatively investigated. The peculiar behaviour of one group of red cells, illustrated by ox, toward influenza virus heated for 30 min. at 56° C. and toward purified N.D.V. has been studied in detail. It is concluded that heated influenza virus acquires an apparently increased titre against ox cells because it has lost its eluting power. Similarly, purified N.D.V. is less readily eluted from red cells, due to the elimination of an ‘elution-hastening factor’ present in infected fluid. The present study illustrates the importance of careful adjustment of all possible variable conditions for individual viruses and individual red cell systems.

Progressive heat inactivation of N.D.V. at 54–58° C. for 15 min. is accompanied by parallel destruction of its haemagglutinating activity. Progressive heat inactivation of Lee virus at 50–54° C. for 15 min. is accompanied by parallel loss of eluting power and ‘enzymic’ action on ‘Francis inhibitor’. Formalin in low concentrations rapidly inactivates both N.D.V. and Lee virus without appreciable impairment of their haemagglutinating activity or ‘enzymic’ function. Higher formalin concentrations acting over several days may, however, produce a slow deterioration of the haemagglutinin of both viruses. It is suggested that heat destroys the infectivity of N.D.V. and influenza virus primarily by abolishing their haemagglutinating ‘enzyme’. The possibility of the existence of independent virus components, all of which are essential for full infectivity of these viruses, is discussed.

1. In a material consisting of 417 cases of typhoid fever and 1055 cases of paratyphoid B investigated over a period of 28 years, infection with S. typhi was found to be considerably more serious than infection with S. paratyphi B. In childhood and among young folk the S. paratyphi B mortality was low, but in the age group over 30 it reached 5%. But even in childhood infection with S. typhi gave a mortality of 8·5%, rising at a higher age to 16%.

2. Of the 1387 patients surviving the infections 13·3% were found to be excreters during convalescence, 11% being temporary and 2·3 % being chronic carriers.

3. Of the temporary carriers, 7·9% were faecal and 3·7 % were urinary carriers. The percentage of temporary excreters was approximately the same for the typhoid and paratyphoid B patients—40% were men and 60% were women. The number of temporary carriers rose with the patients' age, and in the age group over 30 years, about 15% were temporary carriers in the case of both infections.

4. Of the temporary carriers, only one-tenth discharged the specific germ for more than 4 weeks after the cessation of the illness. After an interval of 3 months, it is most exceptional for the carrier state to cease spontaneously. We may, therefore, feel justified in fixing this interval as the dividing line between the temporary and the chronic carrier state.

5. Of the typhoid patients 3·3%, and of the paratyphoid B patients 1·9%, became chronic carriers. Thirty-one of them were faecal and only one was a urinary excreter. There was only one child found to be a chronic typhoid carrier. Chronic carriers were also rare among young folk, and the incidence of this state rose much with age, as many as twelve of the total of thirty-two chronic carriers being over the age of 50. Eleven of these twelve were women, five being typhoid and six being paratyphoid B carriers.

6. Most of the chronic carriers have been kept under control for a long time. The only chronic typhoid carrier to recover spontaneously was a woman, aged 52. Cholecystectomy was performed on fourteen chronic carriers. In all the cases in which the carrier state had lasted for at least a year, gall-stones and chronic cholecystitis were found, and the specific germ was obtained in pure culture from the gall-bladder. A woman who had continued to discharge S. typhi for more than 1½ years after the operation, ceased to do so after this interval. The object of the operation was not achieved in one case.

1. The genus Corynebacterium is common in the vagina. In direct smears forms with exaggerated curvature and staining Gram-negatively may easily be mistaken for vibrios.

2. Attention is drawn to the not infrequent presence of Gram-negative cocci in direct vaginal smears. From these cases Diplococcus crassus, a commensal member of the genus Neisseria, has been isolated. These cocci could be mistaken for gonococci.

3. An unusual organism seen in two direct smears from the vagina is described, and the suggestion is made that it may be Streptobacillus moniliformis.

Two different types of nucleus are found to occur in bacteria. The first is a spherical, central or eccentric body occurring in some types of cocci and in Corynebacteria. By analogy with a similar structure in Azotobacter, it is considered that the nucleus may be of vesicular form, surrounded by chromatinic granules, and resembling the nuclear vacuole of certain yeasts.

The second type of nucleus consists of paired chromosomes, usually either one or two pairs. These chromosomes form fusion nuclei within which chromosome divisions take place; they are then redistributed to a number of daughter cells.

The majority of rod-shaped Eubacteria, including the lanceolate-celled streptococci, have this type of nucleus, which is also found in Myxobacteria. The nuclear cycle is quite distinct from the cytological processes which accompany spore and microcyst formation and germination.

1. Fresh-water fish possess serum agglutinins specific for the bacteria which parasitize their peritoneal and opercular cavities, and also for the bacteria inhabiting the water in which they live.

2. The titre of these agglutinins is low in spring and rises during the summer months, in a manner which corresponds to the summer decrease in infection.

3. Similar agglutinins are found in frogs.

4. These observations provide additional evidence that water bacteria are capable of parasitizing aquatic animals.

The bacteriological examinations of 1616 samples of polluted water from the Melbourne supply revealed that the production of acid and gas in MacConkey or in lactose broth was not always evidence of the presence of a coliform bacillus. There was, however, a marked difference in the number of confirmed samples in the two media. Among 1136 samples incubated in MacConkey broth coliform organisms were isolated by plating in 98·4%, but among 480 samples enriched in lactose broth 10·8% failed to confirm. MacConkey's broth is therefore recommended as the better medium for the presumptive coliform test in Melbourne water.

The technique used in the examination of 1345 samples of water and 73 samples of animal faeces was Wilson's method IV extended by plating from at least one tube giving a positive presumptive reaction at 37° C. to include method I also. In both series of tests coli I appeared to be by far the more numerous type by method I, but when method IV was used the intermediate, aerogenes, cloacae group (abbreviated to I.A.C.) was detected in almost as many samples in water and in 63% of the faeces where the numbers were often very low compared with coli I. Unless I.A.C. was present alone or in large numbers in relation to coli I it was frequently missed by the plating method. Even coli I was more often found by method IV which proved, therefore, to be a more delicate test than method I for both types of organism.

The 44° C. test for coli I proved to be highly specific in Victoria, since few organisms were able to produce acid and gas in MacConkey broth at 44° C. except coli I and organisms which had affinity with coli I rather than I.A.C. This contrasts with results reported from Madras (Raghavachari, 1939) and Singapore (Boizot, 1941) where the test appears to be less specific, but is in agreement with British (Bardsley, 1938; Batty-Smith, 1942) and Argentine (Ferramola, 1940) experience where the 44° C. test has also proved to be of high differential value.

Growth in citrate in method IV was sometimes due to coli I, non-lactose fermenters or Pseudomonas pyocyanea, particularly when lactose broth was the enrichment medium.

Bact. coli II and irregular I were found in heavily and in lightly polluted waters, and were associated rather more often with coli I than with I.A.C. They were seldom found in animal faeces. Irregular II rarely occurred among the organisms cultured, but the evidence suggests that it may be of faecal origin.

The coliform counts on decaying leaves, algae and other vegetable debris found in the sumps and on the screens were very high, and the figures showed a heavy increase after incubation.

Periodic sampling of cow dung left to dry in the open meadow showed that reduction in coliform count was very gradual and largely dependent on the moisture content, and that coli I was still overwhelmingly dominant 3–7 weeks after the samples were voided. Laboratory experiments, in which cow faeces were stored in moist and in dry chambers, gave similar results.

Soil plots low in organic matter were watered with cultures of coli I, intermediate I or aerogenes I and sampled at intervals. All three types tended to die out gradually and there was no question of intermediate I or aerogenes I growing and multiplying under the conditions of the experiment, neither were any profound changes apparent in the biochemical reactions of the three types as a result of prolonged sojourn in soil. Soil which had been heavily contaminated with cow manure 3 years previously still contained large numbers of viable coli I.

1. The nature of the probit-log survival-time relationship in the disinfection of standard cultures of Bact. coli at 51° C. at pH values ranging from 2·8 to 8·8 has been studied.

2. It is concluded that there is a very close approximation to a bilinear form in all cases, though there was evidence that a continuous curve concave upwards and to the left would provide a better fit.

3. Probit limits, corresponding to the range of percentage mortality within which, having regard to the experimental error involved, an observation might lie, have been worked out. The range covered by these probit limits decreases as the percentage mortality rises.

4. These limits have been used to decide whether a bilinear or a single straight line treatment should be applied to certain sets of data. It is suggested that they would often materially assist in deciding the range over which linearity may be assumed in any given case.

1. Data obtained by the disinfection at 51° C. of standard cultures of Bact. coli at pH values ranging from 2·8 to 8·8 have been used for the calculation of the concentration exponents of hydrogen and hydroxyl ions. The times taken to reach various degrees of mortality from 50 to 99·99 % have been taken as measures of the activities of the ions.

2. The formula Cn×t = constant proved satisfactory for describing the data for all the mortality levels and at all the pH values tested except pH 2·8, 6·25, 6·4 and 7·0. In these instances the cultures exhibited heightened sensitivity, though the results at all, except pH 2·8, could be included when the 99·.99 % mortality times were used. The exponents increased sharply at pH values below 3·9.

3. The values of the concentration exponents varied similarly under both acid and alkaline conditions, according to the mortality level chosen. The largest value was obtained from the 90 % mortality times, there being a decrease when both higher and lower levels were employed. The changes were greater under acid conditions, when the values ranged from 0·60 to 0·25, compared with 0·60–0·47 for the alkaline reactions.

4. The mean of the pH values for maximal survival at the various mortality levels, derived from the regressions of log mortality time on pH, was ·51, but this was close to a point of greater susceptibility. Experimentally, maximal survival occurred at pH 6·65, which is very near to the neutral point of water at 51° C.

5. It is concluded that within the pH range 6·25–7.0 the hydrogen and hydroxyl ions were relatively inactive, the effects observed being due to other factors possibly including the action of undissociated water molecules.

The authors acknowledge with thanks the receipt of a grant from Messrs I.C.I. (Pharmaceuticals) Ltd. towards the expenses of this investigation.

1. Anti-mallein and anti-typhoid sera produced in various animal species, including man, have been examined for complement-absorbing antibodies using the complements of the pig, horse, cat, man, dog, and guinea-pig, which is possible if use is made of the conglutinating complement-absorption test as well as the haemolytic complement-fixation test.

2. Complement-fixing antibodies which are not demonstrable when some complements are used may be detected when other complements are used; for example, antibodies to mallein in human antisera were only detected when the sera were tested with horse and cat complements.

3. These early results are published at this stage because of the obvious possible application of these methods in laboratory serological diagnosis. Further work is in progress to elucidate the underlying reasons for these observations.

4. The implications of the results are discussed from the practical and theoretical aspects.

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.

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.

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.

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.

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.

The Toxicity of Methallyl Chloride and Methyl Bromide towards White Rats

By N. van Tiel, 46, No. 2, p. 217

p. 219, column 1, lines 9–11 should read:

“The effect of the several gassings upon those rats which survived was studied during and after treatment.”

p. 220, column 1, lines 12–16 should read:

“This rapid growth rate diminished the differences between the average body weights of the treated and untreated rats.”