(1) Each sample of faeces for these investigations was dried on unglazed porous tiles by the method introduced by Dudgeon. The dried feacal powder was added to the various solid and liquid media used for the aerobic and anaerobic examinations. By this method a large quatity of the faeces was examined, blood agar and boiled blood agar media were used as a routine procedure, and it was unnecessary to employ media which hindered the growth of one organism at the expense of another.

(2) It is essential to control the intake of food during the bacteriological investigations of the faecal flora.

(3) Among hearlthy individuals, dietetic errors, excess of alcohol, and active purgation may temporarily alter the bacterial content of the faeces and increase the numbers of bacteria present, even to the same extent as among patients suffering from lesions of the intestinal tract.

(4) Septic infections of the mouth, throat, respiratory, and urinary tracts may give abnormal bacteriological findings in the faecal flora.

(5) Film preparations of the faeces should be made in every instance, but care must be exercised that the correct technique is employed.

(6) Experience has shown that several media are essential for the aerobic and anaerobic investigations of the faecal flora in each case.

(7) Spirochaetes were found in the faeces in 7 per cent. of the cases and usually in large numbers. There was no evidence to show that they had produced a pathological process in the bowel wall. Short coarse and long delicate spirochaetes occurred. Experience has shown that it is necessary to examine the mouth and respiratory tract in such cases for spirochaetal infection.

(8) Streptococci. One hundred and fifteen cultures of streptococci isolated from the faeces in 50 cases of various kinds were investigated. Eighty-two out of the 115 cultures proved to be enterococci. The morphology of this organism is its most striking characteristic. Twenty-one out of the 82 strains were haemolytic, of which 14 were thermostable and 13 acidified mannite. Many strains believed to be haemolytic streptococci were found on more detailed examination to be enterococci.

Nineteen strains of long-chained streptococci were isolated, out of which 6 were haemolytic, all were thermolabile, but only 1 acidified mannite.Fourteen strains of medium and short-chained streptococci were isolated.Five of these strains were haemolytic, 2 were thermolabile and 8 acidified mannite.

Haemolytic streptococci have been cultivated from the tonsils or sputum with the same cultural reactions and heat resistance as among those found in the patient's faeces, sometimes in large numbers.

Streptococci with similar cultural and haemolytic reactions and heat resistance have been cultivated from the faeces of normal individuals and from patients suffering from various infective processes.

(9) Haemolytic colon bacilli. These occurred in the faeces under varying conditions in 6 per cent, of the cases, and in most instances were found in abundance. In urinary infections the same haemolytic strains may occur in the faeces and urinary pus. Some cases of toxaemia due to the presence of haemolytic colon bacilli in the faeces in abundance, have improved with specific vaccine treatment to a degree beyond that met with in any other form of intestinal infection.

(10) The mucus capsulatus group occurred in 5·5 per cent. of the cases, usually in patients suffering from an abnormal condition. of the intestinal tract.

(11) Slow lactose fermenters were cultivated in 2 per cent. of the cases. They have been found occasionally in the faeces of patients suffering from acute urinary fever due to the same bacillus.

(12) Staphylococci. The Staphylococcus aureus and albus were present in the faeces in this series in about 35 per cent, in adults. They occurred in large numbers in some cases of diarrhoea, but especially in patients suffering from pulmonary infections, and their presence in the faeces in typhoid fever may be of considerable importance. When staphylococci, especially S. aureus, occur in the faeces in large numbers, or persist as shown by multiple examinations, then it is advisable to examine the patient for an inflammatory focus.

(13) Diphtheria-like bacilli were isolated from the faeces in 6 per cent, of the cases. They were larger and coarser than true diphtheria bacilli, but gave a well-marked reaction with one of the modifications of Neisser's stain. They were non-pathogenic to guinea-pigs. Their presence in the faeces appears to be harmless, but they are of importance in children suffering from enlarged tonsils owing to errors of diagnosis which may arise in connection with true diphtheria bacilli.

(14) Anaerobes. B. welchii was cultivated from the faeces in 35 per cent. of the total cases. Robertson's heart muscle medium was the most effective for primary culture. Occasionally gangrenous infections due to B. welchii occurred. There was no positive evidence to show, however, that B. welchii produced acute gastro-enteritis, or acute colitis, but its relationship to certain infections and toxaemias is discussed.

(15) Three types of intestinal flora are referred to: (1) fermentative or saccharolytic, (2) putrefactive or proteolytic, (3) facultative or normal. The importance of diet in all bacteriological investigations of the faeces is established, while an abnormal faecal flora may be rendered normal by a simple diet. The value of lactose, dextrin, and milk for the treatment of intestinal disorders is fully discussed.

(16) Intestinal antiseptics. My observations with so-called intestinal antiseptics has led me to believe that on the whole they are devoid of bactericidal action on the intestinal flora of man. Dimol and colloidal kaolin have been proved to be exceptions in some instances.

(17) The pathology of intestinal toxaemia based on the work of the American investigators by means of closed intestinal loops is considered.

(18) The characteristics of the acidophilus group of organisms is referred to, including their value in controlling the intestinal flora of man, and for the treatment of intestinal disorders by means of acidophilus milk.

(1) Four batches of 60 mice have been injected with comparable doses of B. aertrycke (mutton), taken from broth or agar cultures in different phases of reproductive activity.

(2) The mortality and the average survival time of the mice after injection varied so little amongst the different groups as to justify the conclusion that no difference in the virulence of this organism is detectable during the first week of growth.

1. Working with agar cultures of a strain of B. aertrycke (mutton) it was found that the number of organisms requisite to cause a given opacity was five times as great in a 26-hour as in a 4-hour culture.

2. This difference is probably explicable by the fact that bacilli from young cultures are larger than those from old ones.

3. Evidence is produced which suggests that the opacity method gives a measure not of the number of organisms, but of the total quantity of bacterial protoplasm in the suspension. It should therefore be of special value in the standardisation of vaccines.

4. It is pointed out that the opacity method when used for the enumeration of bacteria is subject to a considerable error, and is hence unsuitable for accurate work.

5. A technique is described for the estimation of the proportion of viable to total organisms in an agar culture.

6. The results obtained are closely similar to those already described for broth cultures.

7. The maximum proportion of living bacilli is reached at the end of the logarithmic phase of growth, when about 80 per cent, of the organisms are alive and capable of reproduction.

8. It seems probable that there is a mortality amongst the bacilli that are generated in the early stages of growth, the least resistant organisms failing to divide.

In discussing a case of meningitis caused by B. paratyphosus B, Brahdy (1925) calls attention to the extreme rarity of such a condition. An exhaustive survey of the literature led Brahdy to the discovery of only eight cases of paratyphoid meningitis, these being recorded by French or German observers.

Haemolytic streptococci have been obtained from throat cultures of 92 per cent. of cases of scarlet fever in the first two days of the disease.

Strains from 210 cases were found to belong to two main serological types, Type I strains being obtained from 119 cases, and Type II strains from 57 cases.

Strains obtained from cases occurring in members of the same family were found to be mainly of the same serological type.

Strains obtained from cases in small isolated outbreaks were found to be of the same serological type.

Note. These Type I and Type II strains have been examined by Dr Griffith, Ministry of Health, Pathological Laboratory, London, and have been found to conform to his main types.

The following summarises the findings elicited from the investigation, the significance we attach to the results and the conclusions we have drawn:

A careful study has been made of the reputed Wassermann reaction exhibited by theserum of certain normal animals with a view to throwing light on the nature of the reacting substance or principle in syphilitic serum.

The heated (55° C.) serum of various normal adult animals may fix complement along with the antigen used in the Wassermann test, e.g. rabbit, ox, sheep, horse, mouse, cat, dog, macacus, pig.

The complement-fixation reaction may be associated with the flocculation effect similar to that of syphilitic serum.

These reactions apparently represent a natural or normal property of the serum and do not appear to depend on any pathological condition.

Certain species, including man, are characterised by negative reactions, e.g. white rat, guinea-pig, frog.

The serum of the white rat in the unheated state, however, yields a definite but weakly positive flocculation reaction which is annulled on heating the serum to 55° C., showing that this species is not devoid of the particular principle. In some species there is great uniformity in the occurrence of both reactions (e.g. rabbit, ox, sheep, horse). Such uniformity has led us to regard the reaction as a natural one. In other species there is less regularity and both reactions in certain individuals may be quite negative. In certain animals there may be dissociation of the two reactions: the Wassermann reaction may be negative while the flocculation effect is positive (e.g. pig, pigeon, fowl, cat): the reverse may occur, the Wassermann reaction being positive, the flocculation test negative (e.g. dog, mouse, rabbit).

Certain positively reacting species are characterised by uniformly weak reactions, e.g. mouse.

The Wassermann reaction in normal animals is always limited in degree, contrasting in this respect with the very marked effects obtained with the serum from cases of active syphilis.

In species in which adult animals exhibit positive reactions, very young animals, e.g. up to 3–8 weeks of age, react negatively. The reacting power (observed in rabbits) is thereafter progressive in development and is parallel with the development of a natural antibody (anti-sheep haemolysin). This parallelism supports the view that these reactions are due to antibody-like principles in the serum.

No constant difference in thermostability of the reacting substances can be established between normal animal serum and the serum in syphilis. The degree of thermostability seems to vary slightly among individuals. The flocculating property is more stable than the complement-fixing principle both in animals and in syphilis.

These reactions in normal animals seem to be homologous with the corresponding reactions in syphilis. Our observations suggest that the syphilis serum reactions are due to antibody-like substances homologous with antibodies natural to certain species and widely distributed among animals.

The Wassermann and flocculation reactions in individual rabbits tested at intervals are relatively constant.

Marked augmentation of the Wassermann reaction has been produced experimentally in rabbits: (a) by immunisation with heterophile antigen, as originally shown by Taniguchi; (b) by experimental infection with B. tuberculosis. The effects of other non-specific agents have also been studied but marked alterations have not been observed.

Repeated subcutaneous injection of alcohol in rabbits abolishes the Wassermann property. The injection of certain other chemical substances also produces a weakening influence. Parallel effects are observed on the antisheep haemolysin.

An analytical study has been made of the Wassermann and flocculating substances in the serum of normal animals and human syphilitic serum. For this purpose carbon-dioxide fractioning of the serum has been used. The results have been recorded and differences have been elicited in the behaviour of the serum fractions between normal animals and human syphilitics. These differences probably depend on the total content of the reacting substances in the serum and their distribution in the serum fractions.

The carbonic-acid-insoluble fraction of normal human serum and the serum of negatively reacting animals even after heating at 55° C. may yield a weak complement-fixation effect with the Wassermann antigen. This property is “masked” in whole serum. It is lost on heating above 60° C. and is more marked in the unheated fraction.

The deviation effect produced by the unheated fraction is contributed to by an independent complement-deviation reaction with the alcohol present in the antigen suspension but is still manifest with alcohol-free antigen preparations, showing it is partly a true reaction with the lipoids proper. This effect of the carbonic-acid-insoluble fraction has not been paralleled in the flocculation test unless in certain exceptional instances.

These observations seem to indicate that the principle in serum responsible for the Wassermann reaction is present normally in minimal amount and in a masked state even in those animals which are negative reactors when tested in the usual way. It might be supposed, therefore, that the diagnostic reaction is due to the non-specific augmentation of this natural antibody-like substance.

The influence of various non-specific agents and different infective conditions on the content of the reacting substances in the serum of normal animals requires further investigation.

The complement-deviation reaction of fresh serum with diluted alcohol (substituted for antigen) has been studied in animals and man. The fact has been elicited that the heated carbonic-acid-insoluble fraction of the serum of animals (positive in the usual Wassermann test) and of syphilitic sera yields, along with diluted alcohol, a definite though weak complement-deviation reaction. This may also occur with heated whole serum. This effect is absent from heated normal human serum and the heated serum of “Wassermannnegative” animals. This reaction shows some analogy with the Wassermann reaction and the alcohol of the Wassermann antigen suspensions seems to be a contributory factor to the total complement-fixation in the Wassermann test. If heated serum is used, no fallacy is introduced in the diagnostic test even when the concentration of the alcohol is 1: 12.

The dissociation of the Wassermann and flocculating properties in syphilitic sera is evidenced as a result of carbon-dioxide fractioning—the soluble fraction being more active in the flocculation test, the insoluble moietybeing more active in the Wassermann test, though in some cases the dissociation is less obvious and may be quite absent.

It is suggested from the observations recorded that the Wassermann syphilis reaction represents an increase of a “lipoidophile” antibody naturally present in the serum in minimal amount and in a masked state, which in syphilis is non-specifically augmented in an analogous manner to the augmentation of the natural anti-sheep haemolysin by heterologous stimuli.

This paper is the result of an attempt to determine if, in the different social classes obtained by a grading of a large section of the male working population of England and Wales for the triennial period 1910–12, as described by the Registrar-General in the Supplement to his 75th Annual Report, there was shown any special susceptibility to cancer in particular parts of the body. From a comparison of the standardised mortality-rates from cancer in 16 different sites in (1) men of three social grades, namely, the upper and middle classes, skilled workmen and unskilled workmen, (2) two sub-groups of the upper and middle classes and (3) men of two social classes, a higher and a lower intermediate to classes 1 and 3 and 3 and 5 respectively, it seems reasonable to draw the following conclusions:

1. The mortality-rates from cancer in the majority of the parts of the body considered, including amongst others the tongue, oesophagus and stomach, which altogether account for 92 per cent, of the total deaths, are definitely higher in the men of lowest social status; the incidence decreases, though not always regularly, with ascent in the social scale.

2. The mortality from cancer in other parts of the body, namely, the bowel, the prostate and probably the pancreas, is definitely highest, however, in men of the best social status.

3. Though the relatively high cancer mortality-rates in these sites in the best social class may probably be attributed in some measure, which it is difficult or impossible to assess, to improved facilities for, and methods of diagnosis in this class, as compared with those in the lowest classes, this cannot be the whole explanation as the differences are considerable and as no increased mortality from cancer is evident in any of the sites except the pancreas with such an ascent in the social scale as takes place in passing from social group 1 b, to social group 1 a, where the influence of more skilful diagnosis might also be expected to reveal itself. If we may accept the mortality from hepatic cancer in the different social classes as an approximate index of the general accuracy of diagnosis of malignant disease therein, then varying accuracy of diagnosis can have little influence in producing the divergencies in mortality from cancer in these special sites that are found in the social groups under review.

4. The excessive mortality from cancer of the bowel amongst males of the best social class cannot reasonably be ascribed to their habits of life such as high-feeding and easy-living or to their alleged greater liability to autointoxication. If this were so, cancer of the stomach and cancer of the rectum might also be expected to show a higher incidence in the same social class; the mortality-rates from cancer in these sites, however, are not higher in this class than in the lower social classes.

The following paper gives some results of a series of experiments on the bactericidal power of various sources of ultra-violet radiation. The “power” of the source was in each case measured by the quartz-cadmium photo-electric cell described by the authors (1925), and it is shown that very definite and practically useful correlations exist between the cell reading and this typical abiotic action.