Although knowledge of principles determining variation is imperfect, some progress has been made and further help may be obtained from some of the newer conceptions about combining affinities regulating normal growth. There are reasons to believe that growth depends on a rhythmic cycle of synthesis, peculiar to living protein, whereby at each successive stage one particular “building stone” is selected for synthesis, with rejection of all others. There is also some evidence that the surface of a growing bacterium passes through periodic phases. Additional light on the activities of the bacterial surface is thrown by the new conception of enzymes which regards them not as fixed chemical entities but as chemico-physical “centres of activity.”

Some of the principles which are gradually coming to light in bacterial variation may ultimately be of assistance in the much more obscure problem of explaining the change from the normal mammalian cell to its malignant variant. I refer in particular to conceptions, which I have discussed in the preceding part of this article, about the mechanism of cellular growth and the nature of a cell's combining affinities.

The following investigation was made, at the request of the Mine Rescue Research Committee of the Safety in Mines Research Board, as to the upper limit of temperature at which air can be breathed without distress under various conditions. During the use of self-contained breathing apparatus in rescue work, the air circulating in the apparatus becomes heated and saturated with moisture, and the question arises of the limiting temperature of inspired air that a man can tolerate while resting and while doing work, and which is therefore permissible for an apparatus.

1. The amount of crystallisable albumin in egg-white and the amount of total globulin in horse serum have been estimated by means of the precipitation reaction. The results are in good agreement with those obtained by other methods.

2. For such estimations it appears advisable to use only antisera prepared against individual proteins.

3. A description of the manufacture and the characteristics of the pure proteins used is appended.

Men engaged in slaughtering and dressing meat show a higher incidence of Brucella abortus agglutinins than those in similar age and sex groups who are otherwise employed, where titres of 1 in 20 and upwards are observed.

This applies especially to men who deal with cattle and sheep; no such increased incidence has been noted in men dealing with pigs.

It would seem that a titre in the vicinity of 1 in 40 serves to indicate evidence of Brucella infection definitely greater than that likely to be found in the generality of the community.

As a result of the extensive investigations in America and on the Continent into the relationship of Br. abortus to undulant fever in man, attention in this country has been directed to cases of fever due to obscure causes, with the result that an increasing number of cases of undulant fever are being reported. So far, however, the cases in Great Britain appear to be less numerous than those in the United States and in Denmark where every effort has been directed to tracing sources of infection and where the conclusion has been reached that, although a certain number are infected by contact with the secretions and carcasses of infected animals, many infections occur through ingesting milk containing Br. abortus.

1. Hydrogen sulphide has been found to have a destructive action on dry anthrax spores.

2. Disinfection of hard, dry, very resistant infected hide specimens, in conditions both of ease and difficulty of access of the disinfecting gas, has been obtained by treatment with hydrogen sulphide at 20° and at 37° C. in periods of 7–16 days.

3. The fact that hydrogen sulphide, in the experimental conditions described, penetrates to the middle of a bundle of leather pockets has been verified by its action in disinfecting (sometimes partially—sometimes completely) anthrax-infected threads placed in the middle of such a bundle.

4. Increase of the temperature at which treatment is carried out has been found to hasten disinfection.

5. Disinfection of anthrax-infected threads has been obtained by treatment with equal parts of hydrogen sulphide and air in 3 days at 60° C.

The author wishes to thank the Council of the British Leather Manufacturers' Research Association for permission to publish this paper, which was submitted to them in the private and confidential report for 1930 of the British Leather Manufacturers' Research Association.

The recognition of small-flaking, granular or “O” agglutination and the conditions under which it occurs have lately assumed importance in the diagnosis and prognosis of enteric infections.

In the operations of bacteria under natural conditions it is the general rule to find mixed cultures at work, the variability of the results depending upon many factors. Therefore it has been suggested by Holman (1928) that the general term “bacterial association” be used to cover such processes. When, however, the combined action of two or more micro-organisms effects changes which each by itself is incapable of achieving, the term “synergism” is applied. Synergism appears to be used now in a more restricted sense to describe a particular type of bacterial association, and has been defined by Fiallos (1925) as follows: “two bacilli neither of which causes the production of gas in certain compounds, may do so when artificially mixed together provided one of them is capable of producing acidity (never gas) in these carbon compounds, and the other though inert to these compounds (i.e. produces in them neither acid nor gas) is capable of producing gas from glucose.” In 1911 Penfold observed the production of gas from a glucose medium in which B. typhosus was growing along with a variant non-aerogenic strain of B. coli communis, the latter having been derived from a typical gas-producing culture by selective growth on agar containing sodium monochloracetate. Although this organism had lost the power of gas-fermenting glucose it retained the power of gas-fermenting sodium formate. Castellani (1925, 1926 and 1927) states that he noted the phenomenon, which he calls “symbiotic,” in 1904 when investigating the fermentation reactions of bakers' yeast, which is not a pure culture but consists generally of two or more species of yeasts together with one or more types of Gram-negative bacilli.

1. The epidemic spread of plague in Java usually shows periodicity in that the increase commences in the third quarter, the driest period of the year, the apex being reached in the last months of the year. Afterwards, still in the middle of the wet monsoon, the decrease commences and reaches its lowest point in the second quarter.

2. This seasonal course of plague—in the mountainous parts of Java at least—corresponds with a distinct fluctuation in the flea index during the same period.

3. Whereas under the climatic conditions of the mountainous regions of Java the flea index usually follows the rise and fall of the saturation deficiency, it has been shown that in British India the influence of the saturation deficiency is in an exactly opposite direction.

The present investigation, was undertaken to test the American suggestion that the higher mean concentration of haemoglobin in males in America, compared to this country, is due to the chronic inhalation of carbon monoxide from the exhaust of closed motor cars (Price-Jones, 1931).

This paper gives some account and results of work conducted on the properties of ethylene oxide, as this compound has been recommended as an insecticide and vermin destroyer, and what is of more importance, as a fumigant for foodstuffs. The concentration recommended is in the nature of 2 lb. per 1000 c. ft. (or 1 part in 60) for 24 hours. It has also been mentioned as a possible agent for use as a lachrymator in war.

1. The outbreak of typhoid fever in the Ecclefechan Special Water District affected 55 per 1000 of the inhabitants (primary cases only).

2. The evidence available indicated the public water supply as the vehicle of infection.

3. A typhoid carrier was found employed in the water-collecting area.

4. Examination of the water pipes after excavation showed that surface pollution might gain access to the pipes conveying spring water to the collecting tank.

5. Secondary cases were few in number, and so far there is no evidence that foci of infection remain as sequelae of the outbreak.

The physiological reactions of two subjects were investigated in air at a temperature of 70–100° F., and of 40–96 per cent. relative humidity. The experiments lasted 3 hours, and one of the subjects performed mechanical work (step climbing) at the rate of 14,000 kg. m. per hour.

The pulse rate was about 10 beats greater in dry air than in moist air of the same wet-bulb temperature. The winter observations agreed well with the effective temperature scale, but did not agree with the wet bulb, the dry-bulb or the kata-thermometer scales.

Acclimatisation effects showed themselves in experiments made at a dry-bulb temperature of 87° F. or more, but only very slightly in those made at 81° or less. Acclimatisation was fairly well marked in the summer, the pulse rate being 5 to 10 beats less than in the winter, and no longer agreeing with the effective temperature scale.

The body temperature corresponded with the pulse rate, for it was 0·3–0·6° F. higher in dry air than in moist air of the same wet-bulb temperature, and was 0·15° lower in summer than in winter. The winter observations agreed well with the effective temperature scale.

The skin temperature of the face was found to depend on the dry-bulb temperature of the air, but that of the trunk showed no agreement with any of the scales. In moist air it was 1° F. lower than that of the face, and in dry air, 6° lower, owing to the cooling effect of increased sweating.

The gross mechanical efficiency fell off slightly at temperatures above 70 or 75° F. It was affected by the dry-bulb temperature of the air as well as the wet bulb, but not to the extent indicated by the effective temperature scale.

The weight of moisture lost by sweating corresponded well with the effective temperature scale. It increased gradually in consecutive experiments made in dry air, and diminished in those made in moist air.

The degree of fatigue experienced in dry air was considerably greater than in moist air of the same wet-bulb temperature, and it corresponded with the effective temperature scale.

Acknowledgments. We wish, to express our indebtedness to the authorities at the London School of Hygiene and Tropical Medicine, and especially to Dr G. P. Crowden, for the facilities offered to us in our work.