The fermentation reactions and some ancillary characters of 102 strains of virulent C. diphtheriae, 31 non-virulent strains and 150 diphtheroids have been studied.

With the possible exception of dextrin which proved to be an unsuitable substance for biological tests all the strains of virulent C. diphtheriae examined were found to have constant biochemical reactions, fermenting glucose, maltose and galactose and having no action on cane-sugar, lactose and mannite.

The strains classified as non-virulent C. diphtheriae had the same biochemical characters as the virulent strains and were indistinguishable from them either on morphological or cultural grounds.

The diphtheroids examined showed great diversity in their power of attacking the carbohydrates used, at least eleven biochemical groups being recognised.

By the use of three carbohydrates, glucose, galactose and cane-sugar 90 per cent, of the diphtheroids in this series could be distinguished from C. diphtheriae by their fermentation reactions. In the remaining 10 per cent, a clue as to the nature of the organism is often obtained from the character of the growth on agar.

Among the corynebacteria examined other than C. diphtheriae no constant relationship was found between source, biochemical, morphological and other characters.

Nevertheless in dealing with members of the genus in pure culture, the morphology, character of the growth on agar and fermentation reactions taken together give useful information as to whether the organism under consideration is C. diphtheriae (virulent or non-virulent) or a diphtheroid.

My best thanks are due to Dr Ledingham for much help and advice given throughout the work and to Dr Atkin and Dr Robison for their assistance in dealing with the lactose and dextrin problems respectively.

IN 1913, Fraenkel and Much1 inoculated monkeys, guinea-pigs, rabbits and dogs intraperitoneally with large quantities of material obtained from two cases of Lymphadenoma, no accompanying tubercular disease being demonstrable. The material was broken down with antiformin, and as a result of the injections, the guinea-pigs died within three months. The authors state that besides finding extensive tubercular disease, there were hard, white nodules, the size of a cherry stone, on the serous coverings of the stomach and mesentery. Also, in addition to genuine tubercular disease of the lymphatic glands, they found giant cells, not of Langhans' type, as well as a stroma rich in fibriles, similar to what is found in Lymphadenoma. The nodules on the serous surfaces showed a picture corresponding to the terminal fibrous stage of a lymphadenomatous focus, with a scarcity of cellular elements.

Two cases of fatal melioidosis are described. The first a robust Indian labourer; the second a well-nourished, muscular European.

Case 1. Gradual onset. Irregular fever. Pain in the epigastrium. No physical signs of disease at first, except enlarged spleen; later, there were signs of consolidation at the bases of both lungs. Constipated at first; diarrhoea came on towards the end and the patient collapsed and died at the end of the third week.

At the autopsy; there were small patches of consolidation in the lungs, composed of minute suppurating tubercles. In the liver there were similar aggregations of small suppurating tubercles and two circumscribed abscesses. The gall-bladder was thickened. The spleen was enlarged and contained septic infarcts and abscesses. In the caecum there were small superficial ulcers. B. whitmori was cultivated from the lungs, spleen, liver and gall-bladder.

Animals were inoculated as follows: A guinea-pig, inoculated in the anterior nares with pus from the liver, died nine days later with caseous inflammation of the nasal passages and a caseous inguinal gland from which B. whitmori was recovered. A guinea-pig, inoculated subcutaneously with pus from the liver, died on the twenty-fifth day with abscesses in the lymphatic glands from which B. whitmori was cultivated. A guinea-pig, inoculated subcutaneously with a culture of the organism, died within sixteen hours from septicaemia. B. whitmori was recovered from the heart and spleen. A guinea-pig, inoculated subcutaneously with an attenuated culture, died on the twenty-fifth day with suppurating buboes and with abscesses in the liver and lungs from which B. whitmori was cultivated. Two horses were inoculated subcutaneously with cultures of the strain of B. whitmori cultivated from the patient. An abscess developed at the site of inoculation, in each case, but the local lesion healed and the animals have, so far, remained healthy.

Case 2. The illness commenced gradually with pain after food, occasional vomiting and looseness of the bowels. The temperature became high and of the swinging type, accompanied by rigors and sweats. The liver was enlarged. The patient died on the twenty-fifth day.

At the autopsy, two large abscesses were found in the liver, the gall-bladder was thickened and there were a few small superficial ulcers in the caecum. B. whitmori was cultivated from the liver abscess. No amoebae were found.

The following animals were inoculated. Two wild rats were inoculated subcutaneously with a culture from this case and both died from septicaemia in less than twenty-four hours. B. whitmori was recovered from the heart's blood. The result of the subcutaneous inoculation of a guinea-pig was the same. A guinea-pig, inoculated in the nostril, died on the fifth day with a cheesy deposit in the nose and septicaemia. Another guinea-pig, inoculated in the same way, but after the organism had been subcultivated repeatedly, died on the twelfth day, with caseous tracheal glands containing B. whitmori. A rabbit, inoculated subcutaneously, died in twenty-six hours from septicaemia with tubereles in the peritoneum. B. whitmori was cultivated from the peritoneum and from the heart's blood. A monkey fed on a culture remained healthy. A pony inoculated intravenously recovered after a week's fever.

This paper contains an analysis of the results of the bacteriological examinations of 184 samples of milk produced by Mr W. G. Symes, Manor Farm, Fordington, Dorset, between April 1st, 1921 and June 6th, 1924.

The farmer holds a licence to produce Certified Milk which is despatched from the farm in sealed glass bottles. The samples were taken at random from the milk as it was bottled and were at once despatched by post to the laboratory, without placing in cold store. The age of the samples varied from 20–24 hours at the time of examination.

The impression has always prevailed, that malaria is the most common disease in Palestine, and that it is more or less highly prevalent in all of rural Palestine. This impression, based as it is on mass experience, is in general correct; but it lacks the certainty derived from statistical data.

1. Immunity cannot be completely explained by antigen-antibody reactions, even if the term ‘antibodies’ be made sufficiently elastic to include various obscure properties which are exhibited, in vivo, in the actively immune animal. Various other factors have to be considered. One of these is the influence of stimuli upon the vital capacities of bacteria.

2. Transmissible bacterial autolysis appears to be due to a stimulus acting upon the growing bacterial cell and leading to the splitting off of a certain number of daughter-cells which are non-viable, and consequently undergo autolysis.

3. Transmissible autolysis is not due to a stimulus sui generis but is no more than a particular incident in the general phenomena of bacterial variation.

4. The secretions of bacteria in pure culture may stimulate, control, or retard their growth and may lead to the production of variants.

5. When introduced into the animal body, bacteria encounter stimulants of animal origin which may be either favourable or unfavourable to their growth and are to be distinguished from the stimulants attributable to the bacteria themselves.

6. One aspect of the differences between natural immunity and natural susceptibility may be interpreted as due to differences in the stimuli inherent in the particular animal species and to consequent differences in their effects upon the particular bacterial species.

7. Similarly, when no better explanation is available, the acquired immunity (active or passive) of a susceptible animal may be interpreted as a change of the animal's stimulant action from one which was favourable (or indifferent) to the growth of a bacterium to one which is adverse, i.e., a stimulant to the reproduction of daughter-cells which are non-viable in the animal body.

8. Leucocytes are one of the sources of material possessing two kinds of properties, viz., (a) stimulant action on the growth capacities of cells (both bacterial and animal) and (b) enzyme action on the constituents which living and dead cells possess in common. The older researches on the characters of leucocytic extracts were occupied with (b), though they may occasionally be linked up with (a), since there are some indications that their leucocytic material was also acting as „lytic substance.”

9. In some cases it must remain, for the present, an open question whether demonstrable antibacterial action is attributable to some more or less obscure enzymes or to what I have termed „stimuli.”

10. A stimulus may be a substance which is also an antibody, and its stimulative properties may be highly specific. But it would be absurd to assume that for each special kind of stimulative effect there is a special and chemically distinctive kind of stimulus. Both stimuli and antibodies usually possess a wide range of different combining affinities which cannot be explained on the „mosaic” theory that each different combination is due to the presence (in the stimulus or antibody) of a different chemical group.

11. A stimulus, as distinct from a food, causes the bacterial cell to function in a particular way but is not incorporated as part of the structure of the cell. This convenient distinction, however, does not imply that there is necessarily a sharp line of demarcation between a stimulus and a food.