Measurements of the rate of ventilation were made on 312 occasions in thirty-one rooms in (a) a block of older flats, (b) a block of modern flats, (c) three villa residences, and (d) a modern university building.

The rate of air change was determined by liberating a quantity of coal gas into the room and measuring the rate of its subsequent disappearance by means of a katharometer.

The effects on natural ventilation of air gratings and flues were studied in unheated rooms in two blocks of flats. The effective orifices of the gratings were 10·5 sq. in. in the modern flats and 6 sq. in. in the older ones. With the air gratings or flues (if any) closed the rates of air change were 0·55 and 0·71 per hour respectively. With the air gratings open the air change was increased to 0·83 per hour in the modern flats and to 1·04 per hour in the older ones.

The flues in the modern flats in connexion with gas fires were 4 in. diameter pipes (cross-sectional area, 12·6 sq. in.); in the older flats the ordinary fire-places were connected to standard flues and the area of the register openings was 53 sq. in. When the flues were sealed, the air changes per hour in the modern and older flats were 0·84 and 0·72 respectively and when the flues were opened these rates of ventilation were increased to 1·17 and 2·06 air changes per hour. In nine rooms in three other houses the average ventilation rates with the flues closed and open were respectively 0·82 and 1·76 air changes per hour.

The ordinary chimney flue, even without a fire at its base, was an efficient ventilator, but the flue of smaller dimensions was far less effective.

With windows open almost any required amount of ventilation could be obtained, and the observations showed that even when windows are opened only slightly the ventilation is distinctly increased. Thus, in flueless rooms of the modern flats, with doors and windows closed, but with the air grating open, the ventilation amounted to 0·83 air changes per hour, but with one casement only open to a width of 3/8 in. it was increased to 1·79 air changes.

The effects of various factors on the rate of air change are discussed and illustrated. Of these, outside wind speed appears to have most influence. The evidence regarding the effect on ventilation of the difference in temperature between the room air and the outside air is very conflicting. In the present observations, when outside wind speed is taken into account, no definite effect of temperature difference on air change is seen. But the experiments were made in unheated rooms and the temperature difference rarely exceeded 10° F., and in the majority of cases was much less.

The various recommended standards of air supply are discussed. Although certain bye-laws require a fresh-air supply of 1000 cu. ft. per person per hour, it is probable that where there is no overcrowding, as in the normally occupied dwelling-room, a ventilation rate of not less than 600 cu. ft. per person per hour should be sufficient to prevent body odours from becoming apparent.

The results of this inquiry show that in closed, flueless rooms, the air supply is likely to be much below 600 cu. ft. per hour per occupant.

On account of the low ventilation rates observed in flueless rooms it is desirable that the question of the use of flueless gas heaters in such rooms be reconsidered.

1. A Clostridium, non-pathogenic to laboratory animals and not producing toxin, but in some ways resembling Cl. oedematiens, was isolated from the hip joint in a case of “bone-taint” in beef.

2. It was demonstrated in the synovial fluid, the periosteum, the Haversian canals, the bone marrow of the femur, and in associated muscular and connective tissue and blood vessels.

3. Examination of forty hip joints from normal carcases indicated that thirty-eight were sterile, one heavily infected with a Streptococcus, possibly of the faecalis type, and one with a rod, probably a member of the Proteus group.

Experiments on the bactericidal action of ultra-violet light have been made to determine the shape of the survival curve and the dependence upon radiation intensity of the rate of death. Bact. coli, Bact. prodigiosum and spores of B. mesentericus were irradiated with approximately monochromatic light of wave-length 2537 A. The survival curves obtained were exponential and the rate of death was accurately proportional to the intensity over an intensity range of 500:1.

By comparing these results with data previously obtained of the action of X-rays on the same organisms it was established that one ionization produced by X-rays is as effective as some hundreds of ultra-violet quanta. This is interpreted to mean that the quantum yield in whatever chemical change leads to the loss of viability in the irradiated bacteria is, for 2537 A., between 0·01 and 0·001.

1. The paper records the results of a study of the serological types of haemolytic streptococci in scarlet fever, and their clinical and epidemiological relationships, with particular reference to cross-infection.

2. Tables are given showing statistical records of scarlet-fever cases which were examined bacteriologically in an infectious diseases hospital over a period of 13 months. In all, 1831 cases were studied, including 471 with complications.

3. In 415 cases in which swab cultures were made from the throat and nose on admission, both throat and nasal swabs yielded haemolytic strepto-cocci in 115, and the nasal swab alone in nine cases (2·5 %). The total number of throat swabs giving positive results was 357. In only two cases were different types of haemolytic streptococci found in the throat and nose.

4. Only a single type of haemolytic streptococcus was found to be present in a series of twenty-eight early cases in which many colonies of the primary culture were examined serologically.

5. More than one type of haemolytic streptococcus was found in the throats of a series of twenty-five individual cases during a period of residence in hospital when swabs were plated at weekly intervals, and many colonies examined from each plate. In only six of the twenty-five cases did the original type persist throughout the period of residence in hospital. A new type appeared to replace the original strain. In one case three types of haemolytic streptococci were present in the throat at a particular time.

6. On the day a complication occurred in a scarlet-fever case only a single type of haemolytic streptococcus was found to be present in the throat or discharge. This suggests that the strain responsible for the complication is present before the complication becomes evident.

7. Many colonies from the swab cultures of seven patients, who developed complications, were serologically examined. On the day a complication occurred a single type of haemolytic streptococcus was found present in each case.

8. The swab cultures of all the patients in a ward were examined daily over a period of 45 days. Of fifty-five patients thirty-seven were infected by two or more types of haemolytic streptococci. Of these the original type persisted for an average of 9 days. Two or three days before a complication appeared the responsible type was present in the throat.

9. 455 cases with complications were studied bacteriologically. In thirty-four the complication was due to organisms other than haemolytic strepto-cocci (7·5%). 280 were due to a type of haemolytic streptococcus other than that with which the patient entered the hospital (61·5%), whereas only ninety-two were due to the same type (20·2%). In forty-nine both the original strain of haemolytic streptococcus and that associated with the complication, could not be typed (10·8%). In patients who had been 2 weeks resident in hospital 90% of complications were due to new types of streptococci.

10. Tables comparing the types of haemolytic streptococci found on admission and during the first day of a complication are appended. Reference to the types found in cases which did not develop complications is also made.

11. The types of haemolytic streptococci and the severity of the scarlet fever produced by each have been correlated in 949 cases without complications.

12. Records are included of a further series of observations made on 390 cases of scarlet fever occurring at a later date. The types of haemolytic streptococci present were compared with those of the same period in the previous year. While type 1 was the prevalent form in the earlier enquiry, type 4 was the dominant form in the later.

This work has been carried out with the assistance of the Davidson Research Fellowship in Bacteriology and certain grants from the Moray Fund. I am indebted to Dr F. Griffith for having supplied me with his thirty type strains and specific antisera. I wish to thank Prof. T. J. Mackie and Dr A. Joe for their invaluable assistance. I also wish to express my gratitude to Dr C. A. Green for his interest in the work and his guidance in the early stages of the investigation. Mr James Craig, technician in The City Fever Hospital Laboratories, deserves special mention for his technical assistance.

1. The four different L1 strains in the writer's possession isolated between 1933 and 1936 have been maintained for a further period without reverting to Streptobacillus moniliformis. The supposition that the L1 is a pleuro-pneumonia-like organism and lives in symbiosis with a bacterium in cultures of S. moniliformis is still maintained by the writer and the reasons for it are given.

2. From a culture isolated from lesions in guinea-pigs and pathogenic for these animals called the “guinea-pig strain”, an L1-like organism of the pleuropneumonia group has been separated, but not yet been maintained for a long enough period to ensure irreversibility. The morphology of the “guinea-pig strain” shows that it is closely related to S. moniliformis though it can be distinguished from the latter by its cultural and pathogenic properties. The morphology of two other cultures, viz. a saprophytic coccus from the skin of a pig and the organism known as Fusobacterium nucleatum, have been described as possibly representing similar symbiotic associations of bacteria and pleuropneumonia-like organisms.

3. Cultural and serological differences between the L4 causing arthritis, swollen glands and abscesses in rats, and the two other pleuropneumonia-like organisms from rats, L1 and L3, are recorded. It has been shown that the organisms occurring in the brains of mice, L5 and L6, and in the joint of a mouse, “M55”, are of aetiological significance for the condition in which they occur. At the same time they differ in their colony type, morphology and serological features.

4. Morphological and serological studies of the saprophytic organisms of the pleuropneumonia group isolated by Laidlaw & Elford and Seiffert from water and soil show that Seiffert's organisms are closely related to Laidlaw & Elford's type “A”. In agreement with Laidlaw & Elford it was found that their type “B” is slightly different from “A” serologically, while “C” is distinct from “A” and “B” and may be regarded as a special type.

These saprophytic types are not antigenically related to the parasitic varieties.

Data are presented which demonstrate a close connexion between the presence of the L3 organism and the pulmonary lesions of rats, but it has not so far been possible to produce the lung infection with the pleuropneumonia-like organism. The cultural and serological features of the L3 organism are given.

1. The effects of morphine, diacetylmorphine (heroin), methylmorphine (codeine), dihydromorphinone (dilaudid), dihydrocodeinone (dicodid) and dihydroxycodeinone (eukadol) upon the rectum are described.

2. Morphine hydrochloride produces an immediate well-marked increase in rectal tone, which returns to normal about ½ hr. later. Waves of increased tone followed by relaxation are seen during the next 3–4 hr., each wave lasting approximately ½ hr. At the 5 or 6 hr. stage the tone is generally subnormal and remains so for many hours afterwards. The amplitude of the rectal movements is slowly increased, reaching a maximum about 3 hr. later, when they are usually very large and much slower than normal. Later the movements decline to a subnormal amplitude. These effects are abolished by the administration of atropine, and subsequent injections of morphine hydrochloride given within a few hours fail to reproduce them.

3. The effects of diacetylmorphine hydrochloride (heroin) are similar to those of morphine hydrochloride, except that it rarely leaves the rectum in a subnormal state of tone at any time during the first 8 hr. following the injection of the drug. In two experiments a slight relaxation beyond the normal limits was observed at the 5 hr. stage, but it was so small as to be negligible.

4. Methylmorphine phosphate (codeine) produces effects upon the tone and movements which resemble those of morphine, but they are always less marked in degree and of shorter duration than those of morphine. With codeine the effects never lasted longer than 30–45 min.; secondary waves of increased tone, such as were seen after the administration of morphine, diacetylmorphine, dicodid or eukadol, were never observed following the use of codeine. The tone level of the rectum was never subnormal at the 5 hr. stage or later. The effects of codeine were always immediately abolished by atropine, after which codeine was ineffective.

5. Diacetylmorphinone hydrochloride (dilaudid) is a very potent drug, producing very marked effects upon the rectum even when very small doses were employed. Small amounts of the drug cause an immediate increase in tone without any change in the character or rate of the movements. Normal tone was re-established 30–45 min. later, when it declines still further to a subnormal level, reaching its lowest level at 70–90 min. Larger doses of dilaudid produced an increase in the amplitude of the movements in addition to increasing the tone. These effects lasted approximately 30 min., when both tone and movements were normal again. The tone level was generally markedly subnormal at the 6–8 hr. stage. The effects of dilaudid were immediately abolished by atropine, after which dilaudid was ineffective.

6. Dihydrocodeinone hydrochloride (dicodid) is a very active drug which produces an increase in the activity of the rectum which is far greater than that produced by morphine, heroin, codeine, or dilaudid. The immediate effect of dicodid is an increase in rectal tone, accompanied by some decrease in the amplitude of the movements. Later the tone decreases far in excess of normal. Secondary waves of increased tone, each one of 15–25 min. duration, were observed to recur during the first 4½ hr. following the administration of the drug. The tone level of the rectum was never subnormal, even at the 8 hr. stage. The effects of dicodid were always inhibited after the administration of atropine, while the subsequent injection of dicodid always produced its usual effects, which were, however, modified and of shorter duration.

7. Dihydroxycodeinone hydrochloride (eukadol) at first increases the tone of the rectum to a marked extent and later the amplitude of the movements. Secondary waves of increased tone, each one of 18–25 min. duration, and separated from the next by an interval of 8–15 min., were observed through the first 2½–3 hr. following the administration of the drug. The effect of eukadol upon the rectal movements is extremely marked. The maximum-increase in their amplitude was generally observed at the 3–3½ hr. stage, when the tone was subnormal. At the 8 hr. stage the tone was always subnormal, while the movements were decreasing in both rate and amplitude. Atropine immediately inhibited the action of eukadol upon the rectum, while the subsequent administration of eukadol always produced a marked increase in tone without much change in the amplitude of movements.

8. Codeine phosphate is undoubtedly the weakest member of this series in so far as the effects produced upon the rectum are concerned, while dihydrocodeinone (dicodid) and dihydroxycodeinone (eukadol) are the most active.

1. A description is given of a new Salmonella type (S. ballerup) with Vi-antigen which was probably the cause of an attack of gastro-enteritis in man.

2. S. ballerup contains a new O- and a new H-antigen, so that the antigenic formula reads XXIX.[Vi].Z14. There is also a slight O-antigen relationship with the XIX-antigen of S. senftenberg.

3. Like S. typhi, S. ballerup has the V-W change of form, as colonies occur with or without Vi-antigen; of these the V forms are much more stable than the W forms. The V forms are O-inagglutinable.

4. As with S. typhi, the V and W forms are already distinguishable macroscopically on agar plates, the V forms being opaque, whereas the W forms are translucent.

5. S. ballerup's Vi-antigen is serologically identical with S. typhi and S. paratyphi C's Vi-antigen.

6. By means of the V form of S. ballerup it is easy to demonstrate Vi- agglutinin in typhoid sera, as there is no need to fear disturbances from O- and H-antibodies.

7. By means of a V form vaccine of S. ballerup mice can be immunized actively against a lethal infection with the typhoid V form.

8. The mouse pathogenity of S. ballerup is very low. There is no distinct difference in the pathogenity of the V and W forms of S. ballerup.