The culture representing the new type to be described was obtained by one of us (S. H. W.) under rather unusual circumstances. Three fatalities occurred at intervals of 4 and 6 months among the children of one family living in Ashington, Northumberland, a coal-mining town of 30,000 population; in each case death was due to acute gastro-enteritis and supervened within 24 hours of their falling ill. On the death of the third child a bacteriological examination was made post-mortem and S. aertrycke found in abundance in the organs. The suggestion was made at the inquest that a carrier must exist in the stricken family and specimens of faeces from the surviving members were examined by S. H. W. From the mother's specimen a Salmonella was isolated agglutinating with the sera not only of S. paratyphi B, but also of S. enteritidis (Gaertner). This Salmonella, which we propose to call S. newcastle, was obviously different from the strain of S. aertrycke obtained from the fatal case, and the suggestion that the mother had been a carrier infecting her family should almost certainly be dropped; she had had no suspicious illness at any time. The probability is rather that conditions in the house and habits of the inmates were responsible for the succession of cases, though no evidence could be obtained as to possible infection of food by rodents, or consumption of food likely to be specifically infected; the sanitation was of poor quality (privy midden).

In the present paper an attempt has been made to devise a method of determining mortality rates at ages from causes of death associated with childbearing. The sources of possible fallacy in this procedure have been discussed, and it is probable that the results found will represent fairly accurately the true course of mortality in this country.

From all causes of death in childbearing, mortality follows this course: beginning with a high value in the age group 15–20, the rate drops to a minimum in the second quinquennium of reproductive life and thereafter gradually increases with age.

The main components of the death rate exhibit a similar age distribution, but other less important causes of death show an uninterrupted increase with age from the commencement of the reproductive period.

Eclampsia is much more common in young women, but this may be entirely due to the greater proportion of primiparae at these young ages. Estimated in terms of first births the death rate increases rapidly and steadily with age, subject to a small exception in the first quinquennium which may possibly be a consequence of unfavourable marital selection at that age.

The high puerperal mortality of young mothers cannot wholly be accounted for by the excessive dangers of primiparity. Evidence has, however, been submitted that these young women are, on the average, a less healthy sample of the total female population at that age and that, apart from primiparity and adverse selection, the death rate from childbed causes probably follows the same law of mortality as of women in general from all other causes of death.

There has been within recent years a decline of nearly 50 per cent, in the puerperal mortality in young mothers of 15–20 and a smaller decrease in the second quinquennium of reproductive life; but there is no evidence of any improvement at later ages. These phenomena have been brought into relation with the change which has taken place in the death rate from all other causes in married women at these ages. The youngest group of married women, relative to unmarried of the same age, were in the more recent period studied in a much more favourable position with regard to their mortality from causes other than those connected with childbearing than they had been formerly. No corresponding improvement has taken place in the relative mortalities from all other causes in older women within the childbearing ages.

These results suggest that the general health of the mother is a factor of great importance in determining the height of the mortality rate in pregnancy.

There are certain demonstrable changes that take place within the gastrointestinal tract during the process of adaptation to external stimuli. The body as a whole reacts in this adjustment to a changing environment. We have presented our evidence and indicated some instances where these gastrointestinal changes can be considered significant from an epidemiological and preventive medicine standpoint.

The loss of the self-disinfecting power, changes in acid-base equilibrium, and other demonstrable alterations within the lumen of the alimentary tract are only a part of the changes taking place in the organism during the process of adaptation to external environmental changes. If certain diseases are associated with a disturbance of the equilibrium between the parasites and the host, then it naturally follows that we must have more information upon the biological mechanism of the host in regard to its changes in susceptibility and resistance to the parasitic environment. Our present knowledge of bacteriology throws little light upon this epidemiological question. It has been the aim of the author to study the mechanism by which the organism adapts itself to certain environmental changes. We have avoided using pharmacological and other artificial agents that would produce body changes, but have restricted ourselves to simple alterations in diet, external temperature and similar mild or natural environmental factors, and followed the mechanism of adaptation to these physiological stimuli.

The loss of the power of a body-covering layer, to destroy bacteria in contact with it, must increase the hazards of invasion of this body surface by bacteria. We have shown that a sudden change in the intra-intestinal acid-base equilibrium leads to an inhibition of the mucosa to destroy bacteria within its lumen and is accompanied at times by the appearance of viable bacteria in the thoracic duct lymph stream.

If an organism does not adapt itself to its meteorological environment, it is more susceptible to its parasitic environment. The same is true of the nutritional environmental factors. Disturbances due to lack of adaptation to climatic changes can in part be offset by altering the diet. The weather and food factors cannot be separated and one can influence the other.

Changes in climate are beneficial to the well-being of the population living in the temperate zones where meteorological conditions are ever changing as compared to the steady cold in the arctic or constant heat as in the tropics. Changes in food are also beneficial. A high protein meal is stimulating. In the tropics where the skin is in a state of over-stimulation due to the high external temperature and humidity the ingestion of an alcoholic beverage to stimulate the splanchnic system before a meal is beneficial. Acidifying an infant's food in hot weather is a common practice. Many such instances could be cited. It seems to be of advantage to an organism to be in a changing environment. The tonus of our physiological systems is not static or fixed, but is ever changing. The more delicate the index used to measure functional changes, the more frequently are such changes observed. These alterations in environment must not exceed the power of the organism to adapt itself to these changes.

(1) A modern pressure steam steriliser is thoroughly tested systematically.

(2) The experiences gained by the different methods employed are compared.

(3) It is shown that if steam is forced through the objects to be sterilised, the penetration through and the heating of the materials are practically effected in the time it takes to fill the oven. A bucket containing four surgeons' smocks and placed in accordance with the new principle, is thus heated in 5 minutes from 24° C. to 126° C. in all layers, by steam at 134° C. (2 atm. pressure). The same bucket placed in current steam at 134° C. with space for the steam to stream round about the bucket, as in ordinary sterilisers, is to be steamed for 40 minutes to get the thermometers in the contents to register over 125° C. In the first case, the samples of earth used are sterile after 5 minutes, in the second, after 30 minutes.

(4) In a series of orientating and purely provisional experiments, it is also proved that a smock bucket can be sterilised throughout at a low temperature, by formaldehyde-aqueous vapours, when these are sucked through the smocks, in accordance with the new principle.

The culture of organisms in a stagnant liquid medium, which is the normal method employed when the products of their metabolism are studied, has obvious disadvantages. The medium is constantly varying in its constituents and physical characteristics; prominent variations are oxygen tension, pH, food supplies and surface tension, and growth phase of the organism. Experimenters are constantly occupied in preparing nutritive media bearing closer analogy to living tissue fluids; but strangely enough little attention has been directed to maintaining the dynamic conditions obtaining when infection takes place. Yet such conditions may greatly modify the metabolism and general pathological activity of the organism.

(1) The unusual organism previously described (1929) has since been recovered from two additional sources, in each case children suffering from dysenteric symptoms.

(2) It is suggested that this organism be named the “Newcastle dysentery bacillus.”

(3) A more extensive study of its biochemical reactions, using Lemco broth (Dudgeon and Pulvertaft, 1927), as a basis for carbohydrates, has shown that these reactions are notably free from variation and that they exhibit decided divergences from those characteristic of certain bacilli often associated with, but not specifically related to, dysentery. They are more or less closely paralleled in the case of the Glässer-Voldagsen sub-group of the Salmonella, and particularly the Dammann strain of Voldagsen's bacillus, but nevertheless show quite definite differences.

(4) Further examination of the serological peculiarities of the Newcastle bacillus has demonstrated that it is difficult to prepare from it a very active rabbit anti-serum, that its velocity of agglutination is low, and that the titre obtained with saline suspensions is higher than that obtained with broth cultures.

(5) Complete absence of agglutination has been the result in tests with B. typhosus, many members of the Salmonella group, including all most frequently met with and also the Glässer-Voldagsen sub-group, and with a number of the bacilli often associated with, but not specifically related to, dysentery. On the other hand, with one strain of B. dysenteriae Sonne (3) there was a suggestion of agglutination and with at least four out of five races (V, W, X, Y and Z) of B. dysenteriae Flexner this was well-marked.

(6) Saturation with a mixed suspension of these five races completely removes all trace of these secondary agglutinins without materially affecting the specific agglutinins for the Newcastle bacillus while, on the other hand, saturation with each of the four strains of the latter has, in each separate instance, practically eliminated the specific and completely removed the secondary agglutinins.

Finally we desire to acknowledge the helpful criticism we have received from Prof. H. J. Hutchens throughout our study of this organism, the facilities placed at our disposal by Dr Harold Kerr, Medical Officer of Health for Newcastle, and the great assistance rendered by the Deputy Medical Officer of Health, Dr J. A. Charles.

1. The addition to the Nairobi prison diet of either a mineral supplement (closely reproducing in composition the ash of cows' milk) or of a small dose of cod-liver oil, or a combination of these two, produced in adult African prisoners a distinct improvement in body weight.

2. Similarly an addition of olive oil and iodine produced a like effect but less in degree. The significance of this will require further investigation.

3. Evidence is adduced which suggests that one of the most important constituents of this soluble mineral mixture is calcium. Thus:

(a) The prison diet would appear on the basis of previous work to be deficient in the absolute amount of calcium present, nor does it seem rich in vitamins A and D. (In this connection it seems apposite to mention that cases of “night blindness” have frequently been reported.)

(b) The blood calcium of the 42 experimental subjects was initially at a low normal level.

(c) In the groups receiving the mineral mixture and/or cod-liver oil (which is a recognised calcium absorption promoting agent) the level of the blood calcium was invariably raised.

(d) As indicated above, the body weights in these groups increased. There appears to be, further, a certain amount of correlation between the increase in body weight and that of the blood calcium level.

(e) Balance experiments show that given favourable conditions (i.e. the addition of the mineral mixture alone or along with cod-liver oil) calcium will be absorbed in amount considerably in excess of that absorbed from the basal diet alone.

4. In the course of the work some evidence has emerged that certain other factors, e.g. intestinal parasites and minimum temperature, may respectively influence the blood calcium level and the body weight increase. Should these prove in future work to be real influences they would not vitiate our present conclusions.

1. Of five experimental subjects—growing East African native boys—four proved to have definitely negative calcium balances on the diet in use at the Nairobi Prison, while the fifth was merely in calcium equilibrium.

2. The diet in question was found to be so low in calcium (0·32 grm. Ca per day) that the occurrence of negative balances is not altogether surprising.

3. These negative calcium balances became positive on the addition of calcium as milk or in a mineral mixture with or without cod-liver oil.

4. Cod-liver oil alone was not effective in bringing about any appreciable reduction of a negative balance.

5. Our findings showed that 0·43 grm. Ca daily was the maintenance requirement for the subjects under experiment. This figure is practically the same as that found by Sherman in a summary of work on white races.

6. On giving additional calcium in a mineral mixture it was found that after the maintenance requirement had been satisfied, as much as 50 per cent. of any excess might be retained. The calcium of milk, on the other hand, was found to be utilised more efficiently; the corresponding retention figure being over 70 per cent.

7. The influence of the various supplements on growth is briefly discussed.

The question of the relationship of the virulent diphtheria bacillus to avirulent forms of similar morphology and fermentative properties has always attracted the interest of bacteriologists. Practically all careful observers agree that avirulent bacilli can never become virulent either in vivo or in vitro. It has been also the experience of most observers that no virulent strain can be made avirulent by laboratory methods. Crowell (1926) and Cowan (1927) have however reported that they had succeeded in isolating avirulent variants from a pure culture of a virulent strain. From the nature of Crowell's experiment, which only records one such change, it seems possible that he may have chanced on a true biological (i.e. uncontrolled) variation, but Cowan suggests that it might be possible to isolate with some degree of regularity “rough” avirulent colonies from virulent cultures. As Cowan points out the procedure is both lengthy and difficult. My own experiments in this direction have been entirely negative, although I have on many occasions tried to isolate avirulent variants from virulent cultures by colony selection and other methods. I have not even been successful with the cultures with which Miss Cowan worked and which she very kindly put at my disposal. Individual colonies of the Park 8 strain have been also tested on more than 700 occasions and have always proved fully virulent when pure. Passage both through a large variety of artificial media and through animals failed to engender avirulent variants.

This paper presents a summary of the work on Plague carried out in the Bacteriological Section of the Kenya Medical Research Laboratory, during the period August, 1926, to December, 1928, in connection with the preparation of prophylactic plague vaccine. It is divisible under the following sections:

A. Preparation of a vaccine of Haffkine type at Nairobi.

B. Tests on rats of the immunising potency of the vaccine.

C. Notes on the application of plague vaccine for human prophylaxis:

I. Experience in Kenya.

II. Discussion of the relative values of agar-grown and Haffkine's plague vaccines.

D. Notes on bacteriology and serology of Bacillus pestis:

I. Growth in fluid cultures under various conditions, etc.

II. Agglutinating sera and absorption tests.

1. There is a lower percentage of positive Wassermanns in cases of malignant disease than in a similar population of non-malignant cases. If buccal cancers are excluded, the percentage is half that in non-malignant cases.

2. Cancer of the tongue and buccal cavity, in which a high percentage of positive Wassermanns is found, is almost confined to males and is probably due less to syphilitic infection than to some factor such as smoking.

3. There is a low percentage of syphilis in cancer of the digestive tract, except in cases of cancer of the stomach, and the incidence diminishes from mouth to anus.

4. Syphilis does not appear to be a factor of importance in cancer of the glandular organs, nor, apart from the lip, in the production of cutaneous cancer.

5. In general, from the above figures there is no evidence that syphilis plays any direct or very important part in the production of cancer.

In the two preceding communications we have discussed the calcium balances and weight increase of natives, both adult and growing, on certain institution diets, with and without additions.

Various considerations pointed to a relative or absolute deficiency of calcium in the above diets. The experimental additions made, therefore, were (1) a mineral mixture reproducing closely the ash of cows' milk; (2) cod-liver oil; (3) cod-liver oil plus the mineral mixture; (4) olive oil plus KI; (5) milk.

41·7 per cent. of the rats in the Oxford district were found to carry Leptospira icterohaemorrhagiae in their kidneys. The percentage infection increases until the animals are mature, reaching a maximum of 56 per cent. among one class of the population, but is less among the oldest rats. There is evidence that the organism is acquired comparatively early in life, and that immunity is obtained after a long period of infection.

Pioneer studies seemed to resolve the organisms of the Salmonella group into four types or groups sharply marked off from one another by their agglutinative reactions: S. typhosus, S. paratyphosus A, S. enteritidis Gärtner and a “paratyphoid B group.” Later work has shown the heterogeneity of the old paratyphoid B group, which approximates to what we may now term the series of diphasic types; and further that S. typhosus and S. paratyphosus A, far from standing in serological isolation, display striking and peculiar relationships to certain members of this series: the flagellar antigen of the typhoid bacillus closely resembles that of the specific phase of the diphasic Stanley type, less closely that of the Bombay type; both in flagellar and somatic antigen S. paratyphosus A coincides with the specific phase of the diphasic Sendai type (typical paratyphus A bacillus of Aoki and Sakai, 1926).

The spermicidal powers of the various chemical contraceptives sold to the public have never previously been compared, and no one has been in a position to say that one spermicide is preferable to another. The only literature on the subject consists of the pamphlets issued by the makers of the different pessaries, and these give little or no information on the length of time taken to kill sperms at stated concentrations. The Birth Control Investigation Committee therefore asked me to undertake this investigation. The work was financed by the Committee, and carried out, with Prof. Goodrich's permission, in the Department of Zoology and Comparative Anatomy at Oxford.

A statistical analysis has been made of the figures collected during the last eight years in the Edinburgh area, relating to asthmatic patients who presented themselves for examination in certain departments of the Edinburgh Royal Infirmary. The figures for males and females are considered separately, and refer to the numbers of individuals who presented themselves at various, ages, and in whom the disease first manifested itself at various earlier ages. In all, complete records were obtained of 193 males and 167 females. For convenience the ages are grouped in five-year periods.

It has been shown that the figures in the case of females agree well with the assumption that asthmatics, no matter at what age they are first affected, gradually cease to suffer from the disease, or at least fail to report for examination, at a rate which is constant and independent of age. In the case of males the agreement between theory and observation is not as good as in the case of the females, but much of the discrepancy results from two or three obviously aberrant figures. Of every 100 asthmatics at any age it would appear that approximately 7 females, or 8 males as the case may be, are transferred to a non-complaining category every year. The absence of complaint may be due to death from asthma, or recovery, or to some other cause, as for example, that by repeated experience the individual learns how to avoid conditions which precipitate an attack.

On this assumption the relative rates of incidence (P) of the disease at various ages have been calculated for males and for females. Both curves fall during adolescence, rise to a maximum, and then gradually fall, but the male curve lags behind the female curve. From these figures the rates of attack amongst the potential asthmatics (p) have been calculated both for males and for females. The curves fall during adolescence, then rise, remaining practically constant until about 45 years of age, when a rise occurs towards unity. For the further analysis of these curves larger numbers of figures will be necessary, in order that confidence may be placed in the results.