Of the chemical structure of antibodies little or nothing is known. It is generally held that the specific properties of an antiserum are closely associated with the globulin fraction. An antiserum may be distinguished from a normal serum by the precipitation of some of its globulins in the presence of the homologous antigen. The formation of a precipitate in a mixture of antigen and antiserum may be explained in either of two ways: (1) The reaction which occurs when antigen is added to antiserum may produce such physical changes in the mixture that normal globulin is precipitated. The reaction takes place between two specific substances, the antigen and the antibody, and is rendered visible by the presence of a non-specific globulin which plays the part of an indicator. (2) Or we may suppose that in the process of immunisation the antigen produces a specific alteration in the structure of the globulin. That is to say, the antibody is a specifically altered globulin, which has undergone some change in its molecular structure, in virtue of which it can react and combine with the homologous antigen.

Louping-Ill as is now known from the work carried out at the Moredun Institute, Edinburgh, during the last 10 years can be transmitted by the tick Ixodes ricinus. Under natural conditions the disease is probably most commonly spread by this means. The possibility that infection might result, at any rate under experimental conditions, by other means than the intervention of an arthropod vector has been the starting point of the following investigation. The nasopharynx as a possible portal of entry was considered first because it is so often incriminated in many of the virus diseases of man. Furthermore, Webster and Fite (1933) and Elford and Galloway (1933) have shown that mice can be infected with the virus of louping-ill by the nasal instillation of potent filtrates or suspensions of infective brain. Fresh importance has been added to this alternative route of entry of the virus by the occurrence of a number of cases of laboratory infections amongst those who have studied the experimental disease. Rivers and Schwentker (1934), who have recorded these cases, give reasons for incriminating the nose as the portal of entry.

Investigations on perspiration, particularly in regard to feet, are not easy to carry out; observations have to be made under a variety of conditions and complicating factors. A man's foot perspiration may be alkaline whilst another's is acid, and the same person may show different reactions on the same day.

In the estimation of the efficiency of germicides it is well established that various factors may have an important influence on the results obtained. Among these factors may be mentioned the effects due to H-ion concentration, temperature, presence of organic matter and concentration of organisms. In connection with the salts of heavy metals such as HgCl2, a source of error is to be found in the bacteriostatic action of traces of the metal Hg introduced into the subcultures with the inoculum (Chick, 1908; Shippen, 1928; Leonard, 1931).

1. Dioxan when given intravenously and by stomach tube to guinea-pigs, rabbits and cats produces a state of drunken intoxication.

2. The minimum lethal dose for rabbits and cats is 1·5 c.c. per kg. intravenously and 2·0 c.c. per kg. by stomach tube.

3. Tolerance is rapidly acquired and recovery is complete after repeated sublethal doses.

4. In human beings lethal doses of dioxan produce primarily a necrosis of the intralobular arteries of the kidney with resulting necrosis of the parenchyma; whereas in laboratory animals, it has a selective action on the convoluted tubules, which undergo an acute hydropic degeneration, causing intrarenal obstruction and anuria with subsequent death from uraemia.

5. The so-called “necrosis” of the liver produced in rabbits with dioxan is a transitory phenomenon due to the presence of glycogen. This may be equally so in the “central zonal necrosis” seen in dioxan poisoning in human beings.

6. It is suggested that the toxicity of dioxan to human beings is relatively low and that large doses are required to produce lethal effects.

Dufton And Bedford (1933) have denied the claim made by me (1932) that bright sources antagonise the “nose-closing” rays given off by dull red and dark sources of heat. They are supported by Winslow, Greenburg and Herring-ton (1934). These five authors have used the same method, viz. the insertion of a well-fitting tube in one nostril of the subject, the connection of this tube with a recording instrument, and the leaving open the other nostril for breathing, the mouth being kept shut.

From the investigations of past workers, from those recently made with modern refinements by Gardner and Venkatraman (1935) and from my own studies, it is clear that in their serological diversity the vibrios rival the group of coliform bacilli.

Some months ago Prof. M. J. Stewart (1933) gave an address on silicosis in which he covered the whole of the pathology of the various types of the disease. It may seem strange, therefore, that the same subject should be chosen for discussion so shortly afterwards. My apologia is that silicosis presents manysided problems and that since Prof. Stewart's paper appeared the claim has been ventured that the cause of silicosis has been demonstrated. Discussions have been taking place during the past twelve months at the Institution of Mining and Metallurgy—discussions stimulating in themselves and showing the necessity of further research along old and new avenues.

1. The results of a study of 19 strains of the so-called Bacterium typhi flavum are given.

2. It is a Gram-negative rod, motile at 22° C., producing yellow colonies on agar and capable of fermenting a range of carbohydrates, but not lactose, with production of acid but no gas. It is not an antigenically homogeneous species.

3. The organism is widespread, especially in air, dust and plants, and thus may be isolated from various animal sources.

4. Prolonged subculture on agar failed to produce confirmation of the claims of certain workers to have observed the appearance of Bact, typhosum as variants of Bact. typhi flavum.

5. It is suggested that any relation of this organism to enteric infections is unproven and that its appropriate place is in the genus Chromobacterium.

1. Whole cultures, suspensions in distilled water, and cell-free filtrates of Staphylococci clot citrated and other plasmas.

2. Whole cultures and filtrates are comparatively thermostable, while suspensions are less so. Partially purified filtrates are likewise less stable than the crude filtrates.

3. The clotting principle is precipitable by alcohol, acetic acid, and ammonium sulphate.

4. The clotting principle is dialysable through cellophane after alcoholic precipitation but not before.

5. The clotting principle is distinct from haemolysin.

6. Sera can be obtained which have a neutralising action on the clotting principle.

7. Pure fibrinogen can be clotted by a staphylococcal filtrate.

8. The clotting principle is distinct from the toxin responsible for local inflammation and fixation.

9. The clot formed by the addition of “coagulase” to plasma is composed of true fibrin.

Adverse atmospheric conditions, such as occur in mines and various industries, have been shown by numerous workers to have profound effects on both the health and efficiency of the industrial worker.

It is now almost universally recognised that a test for disinfectants which is to yield results of direct practical significance must include appropriate “organic matter” in the test mixture. Some types of disinfectant, notably those which act by liberating chlorine or oxygen, are greatly reduced in activity by the addition of only small quantities of any extraneous material with which these elements can combine. Other disinfectants are more resistant to this influence; they are capable of efficient action in the presence of excreta and dirt of other kinds if used in adequate concentration. What this concentration should be under such unfavourable conditions it is necessary to determine, since the degree of interference is not the same for all disinfectants even in the same class, and no constant relationship exists between efficiency under these conditions and that displayed in a medium of distilled water as determined by the Rideal-Walker test. Numerous efforts have been made in the past to introduce tests employing adequate amounts of complex organic matter; few of these have achieved permanence and none popularity. The following short survey of past work is concerned only with what may be termed “excremental” disinfectants; the testing of surgical disinfectants, which may reasonably be held to demand different methods, is outside the scope of this paper.

Fifty-one strains recently isolated from cases of bovine mastitis have been studied in their morphological, cultural and biochemical reactions.

Using their colony appearance in blood agar as the first differential criterion we have shown that the strains differ widely from one another and from the α β and γ streptococci usually encountered in human disease.

The heterogeneity of mastitis streptococci was strikingly demonstrated. From the results of a relatively small number of cultural and biochemical tests it could be shown that no two of the fifty-one strains were identical, in every respect.

The findings recorded suggest that great caution must be exercised in ascribing a bovine or human origin to individual strains of streptococci on the results of cultural or biochemical reactions.

1. Among a series of strains of haemolytic streptococci from thirty-five cases of scarlatina in the first week of illness, fourteen were found to correspond with one or other of Griffith's serological types I, II, III and IV.

2. Of these fourteen strains, twelve were selected for further examination and found to yield a true heat-labile exotoxin completely inactivated by heating for 30 min. at 100° C.

3. The concentration of exotoxin in 0·5 per cent, glucose broth cultures was at a maximum after 96 hours' incubation, and thereafter on further incubation progressively diminished.

4. No qualitative difference could be detected among the exotoxins from the different strains, the test criterion being the dermal reaction in Dick-positive persons.

5. Cultures of organisms of the same or different serological type isolated from the same source and thereafter similarly treated yielded approximately equivalent amounts of exotoxin.

6. Broth culture filtrates also contained an acid-insoluble toxic fraction, the concentration of which increased with the age of culture and which appeared to be identical with a similar acid-insoluble fraction derived from an alkaline extract of washed bacterial bodies.

7. This acid-insoluble fraction was extremely heat-resistant, 3 hours' boiling at 100° C. being required for inactivation. In this respect the acid-insoluble fraction corresponded to the bacterial endotoxins.

8. The acid-insoluble fractions from cultures of the same serological type produced equivalent skin reactions in susceptible persons.

9. The acid-insoluble fractions from cultures of different serological types differed qualitatively as determined by skin reactions.

10. The reaction to crude filtrate was found to be the sum of the reactions to the exotoxin fraction and to the acid-insoluble fraction present in the filtrate.

It is well known that removal of the pituitary gland is followed by alterations in a number of metabolic processes. It was therefore thought of interest to determine whether these alterations involved any changes in certain immune processes, since very little is known at present of the factors controlling them. Our immunity experiments were made on rabbits and consisted in determining the complement content, the bactericidal power and the opsonic activity of the rabbits' serum.

From an outbreak of very mild “typhus-like disease” in Pretoria, which strongly resembled the cases of “sporadic” or “mild” typhus occasionally occurring in that town, a virus was isolated which was studied in guinea-pigs and rabbits, and was found to belong to the typhus-group.

This virus in cross-immunity experiments with virus of South African louse-typhus and South African tick-bite fever and also in other respects behaved exactly like the typhus-like virus the authors on a previous occasion isolated from rats in a South African town where cases of “mild” or “ sporadic ” typhus have been known to occur regularly for many years.

This constitutes evidence that South African “mild” or “sporadic” typhus comes from rats and is communicated to man by rat-fleas.

In southern Africa, therefore, one has to reckon with three typhus-like diseases: tick-bite fever, flea-typhus from rats, and louse-typhus. Tick-bite fever has a primary sore, the tick-bite, as a pathognomic symptom, the other two can only be differentiated satisfactorily from one another by cross-immunity tests.

Agglutination reactions and cross-immunity tests show that South African louse-typhus and South African rat- or flea-typhus are not identical with similar diseases in other parts of the world.

Tick-bite fever is a mild typhus-like disease extending from the Cape to South Rhodesia.

The typhus-like disease of Kenya is not tick-bite fever, and seems to be identical with fièvre boutonneuse.

During the experimental comparison of different types of hot-water heating systems in a school at Easter 1934 about a thousand kata readings were taken. These were taken mostly in pairs, one immediately after the other, and a third reading was taken only when the first two differed by more than about 10 per cent.

The course of mortality has undergone some remarkable changes since the early part of the last century, the period for which official statistics are available. The variations in the death-rates are emphasised when the rates of various countries are compared, and the cause of the difference in the trend of mortality between various countries has been the source of much speculation. The most striking contrast between the course of mortality in two countries is, probably, that discussed by Prof. Greenwood (1924) in his paper, “The vital statistics of Sweden and England” (J. Roy. Stat. Soc. 87, Part 4). He made a comparison between the two countries for the ages 10–50 for two periods. The first period covered the years 1838–54 for England and Wales and 1841–50 for Sweden, the second period was 1901–10 for both countries. The probability of dying for males during the first period was greater in England and Wales between the ages 10–35 than in Sweden. The greatest difference occurred at age 19, when the value for England and Wales was 151·2 per cent, of the Swedish figure. From age 36 the male mortality in Sweden was in excess of that for England and Wales. The female mortality was greater in England and Wales for every age 10–50. In the second period the mortality at adolescence in England and Wales had made such an improvement that it was less than that of Sweden, the probability of dying for males in England and Wales being less than that of Sweden for the ages 10–31. The England and Wales value at age 19 was now only 59·8 per cent, of that of Sweden. From age 32 the male mortality in Sweden was less than that of England and Wales. The female rate for England and Wales was below that of Sweden for the ages 10–36 and above for 37–50. The mortality of 1901–10, of both countries, had shown considerable improvement on that of the earlier period. This decline in mortality has been general and has been shown in the experience of most countries.