1. The association of the α type of Bact. coli, an organism similar to Bact. neapolitanum or to D433 Taylor, Powell and Wright, with gastro-enteritis of infants is further confirmed.

2. A new type of Bact. coli called the β type and differing from the α type in certain of its cultural characteristics and antigenically is described as also associated with cases with similar symptoms.

3. The antigenic structure of the α and β types has been examined, and both types show a well-marked specificity.

4. Either organism can be readily isolated from faeces during an acute phase of the disease, but there may be some difficulty in recovering either during a subacute stage.

5. Both organisms usually disappear from the intestinal contents as convalescence is established, but a certain number of cases have been discharged still carrying them.

6. These organisms can rarely be found in faeces from infants ill with diseases other than infantile gastro-enteritis, or in specimens from adults. When they are found the cases from which they were isolated have usually some history of contact with gastro-enteritis.

7. The actual significance of the association of these organisms with gastro-enteritis has not been determined, but their isolation points to a diagnosis of infantile gastro-enteritis.

8. In cubiclized and open wards the examination of faecal specimens for these organisms provides a means of controlling nursing technique and determining whether or not intestinal cross-infection has occurred.

1. The presence of a new thermolabile an named β antigen has been demonstrated in motile and non-motile coliform, paracolon and Proteus strains, and in Shigella bacilli (Sh. flexneri Sh. flexneri V1 and D19). This antigen can be frequently found in the above types.

2. The characteristics of the β antigen have been described, and its dissimilarity to H, O, Vi, 2, A, B and α antigens has been established.

3. A high incidence of β antibodies was demonstrated in normal human and rabbit sera.

4. β strains of paracolon and coliform b injected intraperitoneally into mice were shown to be more virulent to mice than β minus forms of the same strains.

5. It is suggested that unrecognized presence of β antigen in cultures and β antibody in human and rabbit sera may cause errors in bacteriological and serological diagnoses of enteric infections.

The numbers and types of bacteria in thirty-nine samples of dried whale meat of the 1946–7 and 1947–8 Antarctic whaling seasons have been investigated.

The total number of bacteria was low for this type of product and there were about equal numbers of clostridia and aerobic bacteria.

A detailed examination of the clostridia present showed that they were of types commonly found in material from mammalian sources.

No Clostridium pathogenic to the mouse was found, although some cultures on prolonged incubation killed mice by ammonia poisoning. Ammonia poisoning was produced by injection of cultures and never by oral administration.

‘And the hand of the Lord was heavy upon the Azotians, and he destroyed them, and afficted Azotus and the coasts thereof with emerods. And in the villages and fields in the midst of that country, there came forth a multitude of mice; and there was the confusion of a great mortality in the city.

The results of a field survey of herpes zoster over a period of 18 months are described and the difficulties of such a survey mentioned.

A total of 246 patients with herpes zoster, only 16% of whom had attended hospital, is reported. It is calculated that the yearly incidence in the population was approximately 2 per 1000.

Full investigation and ‘follow up’ was undertaken in 184 cases. These are classified according to the site of the zoster—the dorsal, supra-orbital and cervical regions being affected in almost 90%, the dorsal region alone accounting for 53·3%.

Herpes generalisatus occurred in 7, or 38%, of the cases, recurrent herpes zoster in 6, or 3·3%, while there was one case of motor paralysis affecting lower limb.

The majority of patients were apparently well at the onset of the zoster, but 27 had some associated disease; 5 gave a history of trauma prior to the onset and 2 were related to pregnancy.

The seasonal and geographical distribution is given and, while the numbers are too small for statistical analysis, the disease in 1947 showed two peaks of higher incidence, the one in May and the other in October. Crowding or density of population did not appear to be important, and the disease occurred sporadically rather than in epidemic form.

There was a higher proportion of female cases, but when related to the population as a whole no sex differentiation was observed. Of the patients 60% were over 45 years of age.

There was no evidence that housing conditions or occupation were of aetiological significance or that the disease was more common among any particular section of the community.

Eleven patients had been associated with other cases of herpes zoster before developing the disease, while 3 gave a suggestive history of prior contact with chickenpox.

A condition indistinguishable from chickenpox occurred among the contacts of 10 patients, 12 individuals being affected, and there was one instance of concurrent herpes zoster and chickenpox. Other infections such as mumps, measles and rubella, while as common in association with the onset of herpes zoster, were not so frequently found as the chickenpox condition amongst contacts of the disease.

The results of the survey as regards the relationship of chickenpox and herpes zoster are discussed. It is considered that the evidence does not favour a significant association with chickenpox prior to the onset of herpes zoster, but that the facts are consistent with the view that a condition indistinguishable from chickenpox may follow contact with herpes zoster. It is suggested, however, that this may be a generalized manifestation of the virus of zoster rather than true chickenpox.

The importance of the accuracy of serological tests for syphilis has become more than ever emphasized by widespread testing and more efficient therapy. The problems are reviewed in the light of present knowledge of the specificity and sensitivity of standard serological tests for syphilis. Richardson's modification of the Wassermann reaction is described. The results of this test when applied to ninety-two cases giving doubtful or discrepant reactions by routine tests are presented and classified. The cases were followed up clinically. The results indicate that this simple test is a reliable and valuable adjunct to routine methods, and should be employed widely as a verification procedure.

1. Some sources of error in the testing of quaternary ammonium compounds for bactericidal activity have been investigated. These resolve themselves into (a) errors caused by bacteriostasis, and (b) errors caused by the clumping of bacteria.

2. A suitable technique, free from these errors, is described.

3. Cetavlon in 0·1% solution is a powerful bactericide even in the presence of moderate amounts of organic matter.

4. One per cent Cetavlon will not kill spores at room temperature even when contact is maintained for several days.

5. Bacteria surviving the action of quaternary ammonium compounds retain their virulence.

1. A strain of Boot, coli adapted to growth in high glycine concentrations, which had lost the power of producing ‘gas’ from sugars, was shown to be devoid of formic hydrogenlyase.

2. Formic acid was prominent among the products of fermentation of sugars by this strain.

3. The appearance of formic hydrogenlyase in vitro, in bacteria grown in such a way as not to contain the enzyme, was inhibited by glycine at high concentrations.

One of us (J. G.) is indebted to the Medical Research Council for a grant-in-aid for expenses.

Information relating to post-partum mating has been described in guinea-pigs kept in six small colonies containing variable numbers of the sexes running together continuously in floor pens of standard size. Litters were born on the floor and rearing was communal (Method 1). Three other like colonies were similarly maintained, except that the females in late pregnancy were separated from the male to avoid post-partum mating (Method 2). The conditions of farrowing and rearing were similar to those of Method 1. The data given by thirty-four sows of a closely recorded (stock) colony bred in units of six females and one boar, but in which every litter was born and reared under ‘cage’ conditions (Method 3), were used for comparative purposes only.

Post-partum mating was considered to have occurred only when the interval between the births of any two consecutive litters of the same sow did not exceed 70 days. Of litters born under Method 1, 80% were conceived at post-partum oestrus; the mean gestation period was 68 days. The average inter-parturition interval of all sows breeding under Methods 1 and 2 was 74 and 118 days respectively. The optimal ratio of the sexes in a colony breeding by both methods was judged to be twelve females to one male.

Litter size varied between 3·98 (Method 1) and 3·69 (Method 3) and by all three breeding methods, the proportion of young already dead or that died at birth was about 5%. Deaths were more common in summer months when litter size was maximal.

The post-natal death-rate during the first 28 days of life among young reared communally (Methods 1 and 2) was 10% and was fivefold that observed in litters reared separately by their mothers (Method 3). This death-rate was highest during the winter months due to the difficulty of providing adequate amounts of fresh green vegetables.

The annual output of young guinea-pigs from colonies bred under Method 1 was 62% greater than that from other colonies bred by Method 2. The more rapid sequence of littering did not affect the quality (body weight) of the young at birth or at weaning.

Attention has been drawn to a possible deleterious effect of intensive breeding to the health of the females and their lessened resistance to infection. It has been suggested that, for this reason, the breeding life of the sows should be limited to 1 year.

The effects of radiation from the surroundings on the impressions of freshness of 106 men and 39 women members of the staff of the Building Research Station were investigated during the first 6 months of 1948. Subjects were exposed to three types of environment: (1) where the walls were cooler than the air, (2) where the walls and air were at the same temperature, and (3) where the walls were warmer than the air. The tests were carried out in calm air.

It was found that the difference between the mean radiant temperature and the air temperature affected freshness impressions, but the effect was relatively slight. Environments which felt cool tended to feel fresh, yet a rise in the mean radiant temperature—which would increase the warmth of the environment—tended to produce an impression of greater freshness. At a given equivalent temperature, environments with the surroundings warmer than the air were found to be definitely fresher than cold- and neutral-wall environments. This was thought to be mainly due to the fact that the humidity of the air in the warm-wall environment was lower than that in the other two environments. Changes in humidity insufficient to affect sensations of warmth affect impressions of freshness. Under the conditions of these experiments, and to keep freshness impressions constant, a rise of 1° F. in the temperature of calm air must be compensated by a fall of about 5% in the relative humidity.

The subjects had a distinct preference for the warm-wall environment; 73% of them found it pleasanter than either the cold- or the neutral-wall environment.

Freshness impressions are considered to be related to transient fluctuations in the rate of heat loss from the head.

A heterogeneous sample consisting of eighteen specimens of semen provided by eleven patients was examined. Smears were supravitally stained at 3, 8 and 27 hr. Counts of living and dead spermatozoa, classified into normal and fourteen types of abnormal forms, showed that whereas five abnormal forms were always dead, the remaining types showed varying proportions of dead and living cells. Their rate of mortality was somewhat greater than that of normal spermatozoa.

Over a period of about 10 months samples were taken at frequent intervals from various stages of treatment at two sewage works; one of these was a small rural works treating only domestic sewage, and the other treated the sewage of an industrial town. These samples were submitted to bacteriological and to chemical examination.

The total plate counts, the counts of coli-aerogenes bacteria, and the counts of Streptococcus faecalis in settled sewage were higher in the warmer than in the colder months of the year.

Though the average total numbers of bacteria in the sewage containing trade wastes were appreciably higher than that of the domestic sewage the counts of faecal organisms were somewhat lower.

Treatment at the works considerably reduced not only the polluting strength of the sewage but also the numbers of bacteria. At the works receiving sewage from an industrial town an average of about 80% of bacteria in settled sewage were removed by treatment in the bio-aeration plant, percolating filters, and humus tanks, and a further 8–10% were removed by subsequent treatment in pressure sand or anthracite filters. At the small rural works, where the rate of treatment was much lower, rather more than 90% of the bacteria were, on the average, removed by treatment in percolating filters and humus tanks, and a further 6% by subsequent passage through shallow gravity sand filters.

The final effluents discharged from the works still contained large numbers of bacteria. Their effect on the bacterial content of the streams to which they are discharged may be gauged from the fact that, in the effluent from the small rural sewage works, which was of consistently good quality when judged by chemical criteria, there were on the average about 160,000 cells of faecal Bacterium coli and about 20,000 faecal streptococci per 100 ml. Numbers in the effluent from the works in the industrial town were even higher. Sand filters of the type investigated here could therefore not be relied upon to produce an effluent of good bacterial quality.

The 44°C. test in MacConkey broth, prescribed by the Ministry of Health (1939) for examination of water, was found, when applied to samples of sewage or sewage effluent, to be almost specific for Bacterium coli, type I. Growth with formation of acid in sodium azide broth incubated at 45° C. was found to be an almost specific test for Streptococcus faecalis.

When samples of domestic sewage are treated with doses of chlorine lower than the chlorine demand bactericidal action depends not only on the proportion of the demand satisfied but also on the absolute size of the dose. With doses just sufficiently large to leave residual chlorine detectable by o-tolidine, reduction in the plate count of bacteria after contact for 15 min. ranged in various tests from 96·2 to 98·7%.

With domestic sewage reduction in bacterial count after addition of chlorine is followed, after an interval, by aftergrowth of survivors which rapidly brings the population to its original level or higher. For this interval to be prolonged the initial concentration of chlorine must be considerably greater than the chlorine demand. This accords with the fact that the rapid reaction of chlorine with constituents of the sewage, which occurs in the first few minutes, is followed by a slower absorption which takes place over a prolonged period, so that the initial bactericidal action of residual chlorine tends to be lost after a time. For many purposes the effectiveness of chlorination should be judged not only by the percentage of bacteria destroyed after a short period of contact but also by the interval which elapses before aftergrowth becomes appreciable.

In samples of sewage treated with doses of chlorine sufficient to destroy the protozoa, surviving bacteria eventually reached a level of population much higher than that of the untreated sewage. The majority of such bacteria were found to be Gram-negative, non-sporing rods, which included strains of Proteus and of Pseudomonas pyocyanea. Tests with a pure culture of a species of Proteus showed that the organisms surviving chlorination are not intrinsically capable of reaching a higher population than the parent culture.

When sewage contains small quantities of gas liquor or thiocyanate the bactericidal action of doses of chlorine lower than the demand is much more prolonged than the action of comparable doses in domestic sewage, owing to the formation of cyanogen chloride.

Comparative tests of the action of chlorine and of cyanogen chloride on pure cultures of Bacterium coli in peptone water and on the mixed flora of sewage showed that the bactericidal effect of cyanogen chloride was more persistent than that of a comparable dose of chlorine. With sewage and with some brands of peptone the immediate effect of the chlorine, on the other hand, was often considerable.