1. A simply made selective tellurite medium for the isolation of Corynebacterium diphtheriae and the identification of its types has been described.

2. The ingredients of this medium are easily obtained and can be stored for any length of time making the medium readily available at short notice.

3. Large or small quantities of the medium can be made with equal facility.

4. When grown on the medium, C. diphtheriae will produce colonies characteristic of its type, be it gravis, mitis or intermediate.

5. The appearance of the colonies has been described and has been shown to resemble closely, in the case of each type respectively, the appearances described by the Leeds workers (Anderson et al. (1931)) on their medium in the original papers.

6. The possibilities of the use of this medium for diagnostic routine swab examinations have been briefly referred to.

1. An experiment on the feeding of calves is described, which lasted over 2 years, and which was carried out on a healthy Shorthorn herd free from tuberculosis and contagious abortion.

2. Alternate animals as they were born were allocated, without any selection whatever, to one or other of two groups. One of these was fed on raw, the other on pasteurized milk. Every animal received its mother's colostrum for 3 days before being put on the milk diet.

3. The milk used was taken from the mixed morning's milk of the whole herd. It was divided into two parts, one of which was given raw, the other of which was submitted to low-temperature pasteurization at 145° F. (628° C.) for 30 nun, and subsequently cooled. The animals were fed morning and evening on measured quantities that were in strict relationship to their body weight.

4. In addition to the milk, hay was allowed ad lib. Observations showed that practically none was eaten during the first month, after which each animal consumed about 1 lb. a day, rising to 3 lb. by the eighth week.

5. With the exception of two weaklings which died after 15 and 23 days respectively from causes apparently unconnected with the nature of their diet, all the animals—twenty-five in the raw and twenty-three in the pasteurized group—throve well, and showed no obvious signs of rickets or anaemia.

6. The average increase in weight over the 8-week period for the animals in the raw group was 53·72 lb., and in the pasteurized group 53·86 lb., or 61·18 and 62·94 per cent respectively. This practical identity in weight increase is all the more surprising in view of the fact that the number of bull calves was very much less in the pasteurized than in the raw group.

7. The highest individual gain among the bull calves—one of 80 lb.—and the highest individual gain among the heifer calves—one of 63 lb.—both occurred in animals fed on pasteurized milk.

8. At no time throughout the experiment was any observer, lay or professional, able to distinguish between the two groups of animals.

9. The diet given, though permitting of good skeletal development, was insufficient to fatten the animals. After they had been transferred, however, to a normal diet at the conclusion of their 8 weeks in the experiment, they soon put on weight and within 2 or 3 months were indistinguishable in size or condition from animals that had received a more generous diet from birth.

10. There is nothing in these results to suggest that the nutritive value of pasteurized milk for calves is in any way inferior to that of raw milk.

The observations described in this paper were carried out as a preliminary to a systematic study of the influence of dietetic factors on resistance to infection. The enquiry was initiated under the general direction of Prof. W. W. C. Topley of this School, and Prof. E. P. Cathcart of the University of Glasgow, and has been financed by a grant from the Medical Research Council. It was desired that all aspects of the problem, dietetic, immunological and statistical, should receive full and careful consideration at each stage of the investigation, and that any significant results, positive or negative, should be checked and controlled on a scale that would supply a firm foundation for further studies. To this end, a small advisory committee was formed, soon after the enquiry started, on which Prof. M. Greenwood, Prof. J. C. Drummond, Prof. Edward Mellanby, Dr Harriette Chick, Dr Bradford Hill and Dr Joyce Wilson kindly consented to serve. To all the above, I wish to express my thanks for help and advice. I wish also to acknowledge my indebtedness to Miss J. M. Hatswell for her assistance throughout the greater part of this work.

Co-agglutination between the somatic agglutinins of B. typhosus and B. paratyphosus B occurs more frequently than between the flagellar agglutinins in the sera of typhoid and paratyphoid B fever cases. These co-agglutinins may develop early or late in the course of the disease.

It is suggested that the agglutinin absorption test is capable of distinguishing whether or not true co-agglutinins have been developed to the flagellar and somatic antigens of B. typhosus or B. paratyphosus B.

A new type of pathogenic Salmonella for the fowl has been described. Its somatic “O” antigen corresponds with factors VI, VII of potsdam. It occurs only in the specific phase, but its flagellar “H” antigen contains at least two distinct and separate antigenic complexes, which commonly occur in organisms that are not even remotely related. The one complex (the first, en-, antigen, α phase of Kauffmann and Mitsui) contains factors enx, which represent also the factors of the specific phase of abortus-equi. The other complex (the second, d-, antigen, β phase of Kauffmann and Mitsui) contains factor d, which comprises the type phase of stanley, muenchen and typhi.

Single cells containing factors enx on multiplying constantly yield variants containing factor d as well as offspring that retain antigenic complex enx. In the same way single cells containing apparently only specific factor d will bring forth new cells, most of which retain the parental antigenic structure, but a small proportion of the progeny will acquire specific factors enx instead of d.

When a broth culture of amersfoort in either the enx or d phase in an apparently pure form, as judged by the agglutination test, using heterologous sera which contain agglutinins either against factors enx (or en) or d, is used for the preparation of sera, agglutinins of approximately the same titre for both variants are produced in the sera.

As a result of the information given above the following antigenic structure is proposed for Salmonella amersfoort:

Somatic “O” antigen—VI, VII.

Flagellar “H” antigen—

(1) α phase of Kauffmann and Mitsui—enx.

(2) β phase of Kauffmann and Mitsui—d.

1. An organism is described as a specific cause of black rot in two consignments of hens' eggs imported into England.

2. It produces the rot experimentally when inoculated into fresh eggs, and penetrates apparently normal egg shells.

3. Four hens inoculated with the organisms laid eggs that failed to develop the specific rot. The number of hens used was small, and no definite conclusion about the mode of infection can be drawn from the result of this experiment.

4. The organism is found in English soils and manures.

5. Eleven of 100 English hen sera agglutinated the organism in dilutions of 1 in 80 to 1 in 320.

6. The organism is provisionally placed in the Proteus group, and the name Proteus melanovogenes is assigned to it.

The preceding paper recorded experiments on the influence of various “natural” and “synthetic” diets on the fertility of breeding does, and on the growth and survival of young mice. The present paper records the relative resistance of mice, bred and reared or fed for shorter periods on these diets, to Bact. typhi-murium, or to its endotoxin.

The paper describes a series of observations made in a well-built room in south-west Persia. A study was made of conditions of temperature and humidity in the room, and between the clothes and the body.

Observations were made in the cold and the hot seasons. In spite of the great contrast which prevailed in the room at these two seasons, there was very little difference on the surface of the body.

The observations are consistent with those published by Mellanby, who worked under a wide range of artificially produced climatic conditions.

1. The day-to-day records over a period of 4–6 months of 167 normal women's physical changes and subjective phenomena have been collected by a new method. These women submitted data from 780 complete menstrual cycles. In addition, a smaller group submitted data which have been used for physical changes only. One woman's individual record of certain phenomena was obtained over a period of 8 years.

2. The average length of the menstrual cycle was 27·8 days with a standard deviation of 3·4 days. Some individual's cycles were characteristically short or long, regular or irregular. No woman menstruated with complete regularity (measured in days) over a period of 6 months. Twenty-three per cent of the menstrual periods began between 7.30 and 9.30 a.m., and the average duration of the flow was about 4·5 days.

3. Records from one case of intermenstrual, probably ovulatory, bleeding were obtained over a period of 6 months (Chart 2).

4. The periodicity of each subjective phenomenon as shown by the combined results has been recorded graphically, and these figures themselves constitute a summary of the results. Thus for fatigue, abdominal pain, backache, headache, breast changes, sexual feeling and intercourse, depression, elation, tendency to cry, irritability, intellectual capacity and tension see Figs. 5–19. Individual data of interest have been discussed in the light of the combined results.

1. Guinea-pig vaccination experiments have shown that these animals can be rendered completely immune from infection with virulent strains of L. icterohaemorrhagiae when they are treated with non-virulent living vaccines, or formalinized, heat-killed, phenolized, and dettolized suspensions of virulent cultures.

2. Vaccination with homologous strains of L. icterohaemorrliagiae produced better immunity than when heterologous strains such as L. hebdomadis or L. icterohaemorrhagiae Rachmat are employed.

3. Immune bodies are demonstrable in the serum of guinea-pigs vaccinated with L. icterohaemorrhagiae Weil, and a lytic titre of 1/6 appears to indicate that sufficient protective antibodies are present.

4. Following upon vaccination and inoculation with virulent cultures, carrier conditions have developed in animals treated with chemically killed vaccines of L. icterohaemorrhagiae Weil and with living non-virulent suspensions of the heterologous strain L. hebdomadis and L. icterohaemorrhagiae Rachmat.

1. Of eighty-six strains of Haem. influenzae isolated from the naso-pharynx of normal persons, sixteen had the general characters of Pittman's “smooth” type.

2. These sixteen strains and one “smooth” strain isolated from a case of meningitis were submitted to various serological tests, including the separation and partial purification of a carbohydrate fraction from the meningeal strain and from four of the sixteen strains.

3. By precipitin tests carried out with these purified fractions, it was possible to identify three of the five “smooth” naso-pharyngeal strains and the meningeal strain, as belonging to Pittman's type e, and one of the “smooth” naso-pharyngeal strains to Pittman's type a.

4. Some indication of grouping, within this small sample of smooth strains, was obtained by various other methods, such as precipitin tests carried out with simple saline washings or agglutination reactions; but, apart from the four type strains a, b, e and f, received from Miss Pittman, no strain could be satisfactorily typed by any of these methods. Only by using partially purified polysaccharide fractions was it possible to assign any of the “smooth” nasopharyngeal strains to their correct type.

5. The testing of these naso-pharyngeal strains against antisera prepared against types a, b, e and f by direct agglutination, showed that either many of these strains contained some proportion of the smooth antigens, or that the antisera contained antibodies acting on other antigenic components, although, in relation to the type strains themselves, they appeared to be specific.

6. The examination of the eighty-six strains, as a whole, revealed the extreme antigenic heterogeneity that has been noted by many previous workers.

1. By means of a new technique, using the “closed bowl” of the Sharpies-Super Centrifuge, in which the distance which the virus particles have to travel under the influence of a given centrifugal force until they are caught mechanically in an agar-gel lining the wall of the bowl amounts to only a few tenths of a millimetre, the potency of 5 c.c. of a foot-and-mouth disease virus suspension can be reduced by 90–99 per cent in 3 min. using a centrifugal force of 24,000 times gravity. The virus can be recovered without loss by extraction of the agar-gel either in fresh medium or even in the liquid layer or “supernatant”, thus showing that adsorption phenomena play no role whatever in the effects obtained by centrifugation.

2. The non-adsorbability of the virus by the agar, however, is determined by the presence of a certain though very small amount of impurities presumably protein which seem to have a “protective” effect. The limit of nonadsorption of the virus by the gel appears to be in that region of “purity” where the sulphosalicylic acid test for protein is negative whereas serological precipitation reactions for host protein are still positive. Virus purified beyond this limit is strongly adsorbed by an agar-gel.

3. Measurements of the sedimentation rate were made on three strains of virus of different type Vallee A, Vallee 0 and Waldmann C and no differences between the three strains were observed. The average diameter of the virus particles determined from the sedimentation rate data was 20 mμ. All the evidence now available for the monodispersity of the virus is discussed. The fact that the infective particles are uniform in size indicates that the measurements recorded here concern actually the single virus elements.

4. The sedimentation equilibrium of the virus has been estimated. The value calculated on this basis for the weight of a single virus particle is circ. 1 × 10−17 g. The diameter of a sphere of this weight and density 1·30 would be 25 mμ. The size values for the virus, 25 mμ estimated from sedimentation equilibrium data and 20 mμ estimated from sedimentation rate data, are discussed in relation to the possible shape of the virus particles.

5. The virus can be sedimented in sucrose and sucrose-salt solutions of densities up to 1·28. On the basis of the sedimentation rates in these media the specific gravity of the virus particles is estimated to be about 1·40. This value however may be abnormally high due to the dehydrating effect of the high concentration of salt or sugar. The application of the centrifuge technique described here to the concentration and purification of the virus of foot-andmouth disease in conjunction with ultrafiltration methods will be the subject of a second paper by Galloway & Schlesinger (1937).

1. It is possible to concentrate the virus of foot-and-mouth disease on filter candles coated with acetic acid collodion. The degree of concentration of the virus effected was to the limit of expectancy, i.e. the increase in titre after concentration corresponded to the reduction of the volume of the liquid.

2. By a combination of the two methods of purification of the virus, viz. washing once in the closed agar-lined cylinder of the Sharpies-Super Centrifuge and repeatedly on a graded collodion membrane of A.P.D. 25 mμ, very potent purified concentrates of virus can be rapidly obtained, especially if the final concentration is made on filter candles, coated with acetic acid collodion. In this way a concentrate of virus with a titre of 10−8 and a negative sulphosalicylic acid test for protein has been prepared in one day from virulent vesicle lymph (diluted 1 : 2) having a titre of 10−6.

3. The possibilities of the different methods of purification and concentration of the virus are discussed and a scheme suggested for their application.

The rapid decline of the birth-rate in nearly all countries of western Europe has naturally attracted much attention. Some have studied the probable effects upon the absolute size and the age constitution of the population, and the consequence entailed upon the military and economic strength of a nation. Others have drawn attention to resulting change's in the relative importance of diseases of young, adult and old ages. Changes in mere numbers depend wholly, and the other changes to a considerable extent, upon quantitative factors; they must occur even if the quality of those born differs in no way from that of those produced when fertility was at a higher level. But, if the quality of births changes with their quantity, then the consequences of decrease of numbers may be better or worse than mere numerical changes would involve.

The Flexner dysentery bacilli are non-flagellated, and their agglutination is determined by somatic antigens situated at the cell surface. So far as the author is aware, phasic variations, of the kind that Andrewes (1922) demonstrated in the flagellar antigens of the bacilli of the typhoid-paratyphoid group, have not yet been observed in the case of 0 antigens; but the variations described above would appear to be of this type. The V, W and Z strains examined gave rise to variants, such as Vb, that had lost, completely or almost completely, the group somatic antigen, or antigens, but showed a consistent tendency to revert to the form in which the group antigens were present.

No evidence could be obtained of variants in which the group antigens were present, while the specific antigen was lacking; but the substrains, such as Va, that showed the presence of both group and specific antigens, appeared to differ from the parent strain in showing no tendency to give rise to variants of the Vb type.

Accuracy of titration may be taken as a measure of the reliability of the methods and work of a laboratory.

With such a small number of titrations as four, a convincing mean, representing the most probable true titre, is hard to calculate. A fairly close approximation, however, is possible in the form of the geometrical mean.

It is also possible to correct for constant local factors which cause the titrations of a given laboratory to run above or below the mean. By all methods of titration a surprisingly large proportion of large errors are recorded.

The most consistent results, with the smallest proportion of large errors, are obtained by the prearranged standard method with a single standardized suspension. The H titres are rather more consistent than the O; probably because H agglutination is easier than O to read correctly.

Local methods give greater differences than the agreed (standard) method. Since the H suspensions used in one laboratory were also sensitive to O agglutination the supposed H titres are unreal, and cannot be treated statistically.

Local O methods give a considerably greater range of error than the standard method, as is shown by a comparison of the mean errors of Tables II and IV, and by the percentages of errors over and under 100 per cent given in Table VI.

The full titres (H or O or both) of the serums measured by local routine Widal methods, with living suspensions in two laboratories and killed ones in the other two, show a considerably greater proportion of large differences than are shown by the titrations with the standard method. They do not, however, differ more widely than the titres obtained with local O suspensions.

The results of the laboratories that use killed H and O suspensions in routine work are more consistent and accurate than those of the laboratories that use living suspensions.

It is suggested that gross technical mistakes are a commoner cause of error than is usually supposed. Errors of dilution of the serums and other technical variations must also be responsible for a part of the very wide range of differences observed.

The use of old strains, tending to roughness, is to be avoided.

1. A further improvement in the modified McLeod's medium (Gaze, 1933) has resulted from the substitution of saccharose for glucose with the addition of Andrade's indicator.

2. Of the total positive swabs, the saccharose-containing medium detected about 22 per cent which were negative on Loeffler's medium, whereas it failed to detect only 0·36 per cent.

3. On this medium colonies typical of the gravis, intermediate and mitis types are formed and can be easily differentiated with the aid of a hand lens. It is also invaluable for the isolation of pure cultures.

In earlier papers (Gordon, 1930) it was shown that congo red has an inactivating effect on serum complement, both haemolytic and bactericidal, and that this effect can be reversed by treating the serum and congo red mixture with charcoal, the charcoal removing the congo red and leaving the complement active again. A similar reversal of inactivation is obtained by using instead of the charcoal, heated serum (55° C. for 30 min.) or protein solutions. Later (Gordon, 1931), it was shown that congo red had an inactivating effect on the haemolysins of Streptococcus haemolyticus and B. welchii. The reversibility of this effect was not so easy to demonstrate as with complement. Charcoal had a destructive effect on the haemolysins and so could not be used. It was found, however, that when the concentration of congo red was just sufficient to neutralize the streptococcal haemolysin, the addition of cuprammonium artificial silk adsorbed the congo red and liberated the haemolysin. In the case of B. welchii this method of reversal was not suitable, as the artificial silk had a destructive effect on the haemolysin. Instead, reversibility was demonstrated by adding ox serum to the mixture of congo red and haemolysin. This brought about a redistribution of the congo red between the ox serum and the haemolysin and if the amount of congo red used had been only just sufficient to neutralize the haemolysin of B. welchii, then the haemolytic activity could again be demonstrated. Gordon and Robson (1933) showed that congo red interfered with the anaphylactic reaction tested both in vivo and in vitro, the guinea-pig uterus being used in the in vitro experiments, in which the inhibitory action of the dye was shown to be reversible. It was suggested that the congo red interfered with the entrance of antigen into the cell.