Fatal general infection can be readily production in mice by spraying with pneumococcal culture in a closed chamber without resorting to any artificial means of lowering the animal's resistance.

In the experiments recorded the proportion of unprotected mice which developed septicaemia varied considerably, the highest being nine out of ten. These irregularities may be partly attributable to variations in (1) the fineness of the spray, and (2) the virulence of the culture.

In unprotected mice death from septicaemia rarely occurs before the 3rd day after spraying and may be delayed for a week or more.

Vaccination by subcutaneous and intraperitoneal inoculation with heated cultures afforded protection against infection by inhalation to 11 out of 13 mice. Two succumbed to septicaemia although they had resisted 14 days earlier an intraperitoneal dose of 0·0001 c.c. of culture. The culture used for spraying was evidently in a highly virulent state since nine out of the ten controls died of septicaemia.

The above experiments were with homologous cultures but tests have also been made of the efficacy of vaccination against heterologous strains. For example, vaccination with Types I and II cultures gave apparently a certain amount of protection against infection by spraying with a mixture of Type III and Group IV strains.

Passive immunity induced by an injection of antipneumococcal serum immediately before spraying was effective against the homologous types in all of a batch of 13 mice. The resistance showed a tendency to diminish with the lapse of time, since on re-spraying the same lot of mice 3 weeks later one mouse developed septicaemia.

In unprotected mice where death was delayed for some days after spraying there was generally no evidence to the naked eye of any local pulmonary lesions. Rarely typical grey consolidation of portions of the lungs was found. A pneumonic condition occurred more frequently in mice in which a slight degree of immunity had been produced. For example, a Type II pneumonia was found in a mouse which had been immunised against Type I.

The production of the carrier state is a regular sequel to spraying even with the most virulent cultures of pneumococci. A large proportion of the mice which survived spraying were nasopharyngeal carriers a fortnight later and the condition persisted in one mouse for 99 days. A carrier of pneumococci may succumb to septicaemia 15 days after the date of infection; it is not known whether any immunity develops in carriers.

The presence, about the pharynx of mice, of Gram-negative bacilli which grow rapidly in culture and are of high virulence when introduced parenterally is a source of difficulty in attempts to demonstrate pneumococci.

An attempt was made to ascertain whether, after spraying, nasopharyngeal carriers of pneumococci were more numerous among normal or among protected mice. The results were inconclusive, but there was no marked indication in the experiments recorded that the state of immunity influenced the carrier condition.

(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.

In a Memorandum circulated through the Colonial Office, the Cancer Committee of the Ministry of Health expressed a desire for any available information as to the incidence of cancer upon persons of different races living under similar conditions. While there are a good many parts of the world in which considerable numbers of people of different races live side by side, in few of such places are records available for the purpose of a statistical enquiry.

1. In the intradermic test virulence of “morphological diphtheria bacilli,” 0·2 c.c. containing 100 million organisms is injected. The control guinea-pig receives 500 units of antitoxin the night prior to the test. The test animal receives 125 units six hours after the injection of the cultures. A known virulent organism is always injected as a control; 12 to 20 cultures can be tested on one guinea-pig.

Of 2368 swabs received, 1388 (59 per cent.) showed morphological C. diphtheriae. Fromthese 1286 pure cultures were isolated (92·7 per cent.). In 234 positive swabs from cases of clinical diphtheria, in a series examined under very favourable conditions, morphological C. diphtheriae were obtained in 231 (98·7 per cent.) and of these 229 (99·1 per cent.) were virulent. In 758 positive cultures from carriers morphological C. diphtheriae were isolated in 715 (94 per cent.); 50 per cent. were virulent C. diphtheriae, 39 per cent. avirulent, 3·6 per cent. of Hofmann group, 0·3 per cent. Xerosis and 6.4 per cent. unclassified diphtheroids.

3. Only one culture of intermediate virulence was found, i.e. uncertain reactions occurred with a dose of 100 million organisms while clear reactions occurred with 1000 million.

4. Out of 626 positive cultures from cases of diphtheria, both virulent and avirulent bacilli were isolated in two instances, once from the throat and once from the nose.

5. A monovalent antitoxin (Park Williams 8) nenutralised all of 819 virulent strains.

6. Amongst 39 cultures obtained from the ear in post-diphtherial conditions, virulent C. diphtheriae were isolated fourteen times.

7. Impure primary (“field”) cultures gave reliable results (94 per cent.) when more than one-third of the organisms seen in the smear made from the overnight culture were morphologically C. diphtheriae. If fewer C. diphtheriae were present in the smear th e primary culture gave uncertain results.

The present investigation deals with the routine bacteriological examination of 525 samples of water, 265 of which contained lactose fermenting bacilli; 1441 strains were isolated and various differential tests were used in the classification of these organisms.

All the strains were tested in dextrose phosphate culture for the methyl red and the Voges and Proskauer reactions, and although most of them gave normal results (M.R. + V.P. 0 or M.R. 0 V.P. +), there were 25 strains, 1·73 per cent., which gave either double positive or double negative reactions. Similar cases have already been discussed in an earlier portion of this paper, and they leave no doubt that there are types which may vary from the normal as far as the methyl red and the Voges and Proskauer reactions are concerned. At the same time these abnormal types are not sufficiently numerous to make any real practical difficulties in the use of these tests for routine purposes.

The Koser test, considered by many bacteriologists to be of great differential value, was found to give imperfect correlation with the other reactions.

1395 strains were isolated which could be classified in the B. coli group as a result of the production of acid and gas in lactose, the clotting of milk, and the non-liquefaction of gelatine, but when the methyl red and the Voges and Proskauer results were considered it was found that nearly 11 per cent. of these strains were of the B. lactis aerogenes type, and were therefore of no value as indicators of faecal pollution.

The indol reactions were somewhat variable. Among 1244 strains of the B. coli type (M.R. + V.P. 0), more than 10 per cent. failed to produce indol; while among 151 strains of the B. lactis aerogenes type (M.R. 0 V.P. +), nearly 51 per cent. were indol producers. Preliminary extraction with ether was carried out with 448 of these strains before Böhme's reagent was added. With this technique it was found that among 400 methyl red positive types there were 87 strains (22 per cent.) which produced no indol, and among 48 methyl red negative strains there were 12 (25 per cent.) which gave the reaction. Chen and Rettger (1920) were unable to establish any definite correlation between the indol test and the other reactions.

When the sample results were studied, it was found that although 262 waters contained organisms which were included in the B. coli group on the basis of the lactose, milk and gelatine tests, nearly 6 per cent. of these samples contained only organisms which gave a methyl red negative, Voges and Proskauer positive reaction, and were probably associated with pollution from soil washings rather than contamination from faecal sources. This means that the application of the methyl red and Voges and Proskauer reaction does make a considerable practical difference in the interpretation of results in the bacteriological examination of water.

More detailed examination as regards the fermentation of the various carbohydrates is useful for purposes of classification, but is of no significance, in the light of our present knowledge, in assessing the probability of excretal pollution.

It is suggested that, in considering the results of a bacteriological examination of water, organisms should be regarded as significant which are of typical morphology and staining reaction, produce acid and gas in lactose, fail to liquefy gelatine, clot milk, and give a positive methyl red and a negative Voges and Proskauer reaction. The production of indol in a medium containing peptone may be added as an extra test if desired, but the available evidence does not suggest that failure to produce indol is a sufficient basis for the exclusion of an otherwise typical bacillus from the B. coli group.

My thanks are due to Dr G. D. Dawson, in conjunction with whom the present investigation was started; and also to Prof. W. W. C. Topley whose interest throughout the course of the research was made manifest by his helpful advice and criticism.

It is the thesis of this paper that Mendel's principle of varitaion, formed from the study of the genetics of higher plants and animals, can be applied also to bacteria, and that acquired virulence in bacteria is the result of Mendelian variation.

(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. “Antigens” of varying sensitivity may be prepared by coating a dispersion of gum benzoin with saponin.

2. Using suitable dispersions so prepared a zone of precipitation is observed which is more extended for specific than for normal sera. Differentiation is more pronounced as the region of the isoelectric point of the globulin is approached.

3. Precipitation is effected by the ions of salts present in the solution discharging the negative antigen suspension which has been sensitised by the protein of the serum.

4. The mechanism of sensitisation is described.

5. Both albumins and globulins can protect or sensitise gum benzoin suspensions, the effect depending on an appropriate dilution. This effect occurs qualitatively irrespective of the hydrogen ion concentration of the medium. Quantitatively the position of the zone of precipitation and its extent is contingent on the reaction of the medium.

6. The euglobulin fractions of normal and of luetie sera deprived as far as possible of their lipoids can be differentiated both by the Wassermann test, and by precipitation tests.

7. Delipoided euglobulins from horse serum will yield a Wassermann positive reaction when used in certain concentrations. In more concentrated solutions an anticomplementary effect is exhibited.

8. Evidence is presented for the view that the euglobulins of specific sera differ rather in their composition or state of aggregation than in quantity from the euglobulin of non-specific sera.

9. The changes in sensitising power and in the Wassermann reactivity of euglobulin caused by repeated freezing or exposure to ultra-violet light run a parallel course.

10. Attempts to change the Wassermann properties of normal sera are briefly described.

Except in the West Australian pearl fisheries most of the world's diving is done in shallow water, from small boats or piers; and in civil life each diver is independent and controls the situation according to his own lights. In the British Navy the divers work under an officer who directs all the above-water side of things, such as the arrangements for pumping down air, and deciding whether or not it is safe to dive in existing circumstances. Though the officer will have had a short training at the Naval diving school he is not necessarily experienced in under water work; but he will be a seaman possessing knowledge of boat management, weather, and tides, with the authority to give and enforce orders which the young diver lacks. For simple shallow water work the first system is probably the better, though hardly practicable in a disciplined service where the divers are recruited from the lower ratings.

The analysis of a series of haemolytic streptococci of scarlatinal origin by agglutinin absorption experiments has revealed the existence of three chief types. Among 81 strains from scarlatinal throats 37 have been shown to belong to one or other of the three types; 12 have been classified as Type 1, 14 as Type 2 and 11 as Type 3. In addition, two strains have been found which absorbed the agglutinin from both Types 1 and 3 sera.

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.

The life tables that have been constructed from the recorded mortality in England and Wales as a whole at more or less regular intervals since registration of death was introduced in 1837, and those that have been prepared for special districts and cities at various times since that date, afford accurate information regarding the average length of life at different periods during the greater part of last century. There is still comparatively little known, however, about the mean duration of life, and the conditions of health on which it so largely depends, amongst those who lived in the British Isles in pre-registration times and the present paper contains the results of and attempt to supplement existing knowledge on this subject. The data on which the paper is based have been derived from two sources, namely, the Index and Epitome of the Dictionary of National Biography and Burke' Peerage and Baronetage. In the first of these are records of the dates of birth and death with brief summaries of the life histories of persons who were selected as being wminent in various spheres of life in the British Isles and the Colonies from the earliest historical period; in the second are given the genealogical histories of members of the different titled families.

(1) The source, cultural characters and serological properties of a new food-poisoning type of Salmonella are described.

(2) The value is emphasised of Andrewes' discovery of the group and specific phases in Salmonellas.

(3) Alteration of phase from group to specific can be produced by growth in group serum and vice versa. This device is useful in determining the sero logical type of strains which persistently appear in the group phase only.

Pasteurisation at 62.8° C. (145° F.) for 30 minutes leads to a marked reduction in the total bacterial content of milk, varying for different specimens from 94 to 99·8 per cent., when the process is carried out under the most exact conditions. At lower temperatures, e.g. 60° C., the percentage reduction may vary widely—from 51·6 to 97·4 per cent. The percentage reduction has been found to be slightly less when the same specimens of milk are pasteurised in a large scale apparatus than when treated in small quantities under laboratory conditions, the average reduction being 91·2 per cent, in the former case and 98·4 per cent, in the latter. The reasons for this are discussed.

An effectively pasteurised milk should not contain lactose-fermenting bacilli in 1 c.c, and the B. coli content is a valuable index of the efficiency of a pasteurising process.

Milk containing B. tuberculosis, when pasteurised at 62·8° C. for 30 minutes (1) in tubes in a water bath in the laboratory, and (2) on a large scale by a commercial plant, is rendered non-infective to guinea-pigs. By laboratory pasteurisation, even at 60° C. for 30 minutes, milk containing tubercle bacilli is rendered non-infective.

In connection with recent investigations on the spread of bacterial infection among mice, the possible effect of variations in the virulence of the infecting organism has, inevitably, formed one of the problems for study.

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 “Radiation Integrator in Vacuo” is an instrument designed by a biologist, to assist in the study of solar radiation, as received on the surface of the earth. The principle of the instrument is that a black bulb in vacuo is exposed to the sun's rays; the bulb, which contains alcohol, is connected to a graduated stem maintained at shade temperature; radiant heat from the sun causes alcohol to distil over the bulb into the stem where its volume is measured. In Samoa the shade temperature is practically constant throughout the year, but one believes on theoretical grounds that more radiation is received from the sun between September and March than at the other season, and that the radiation has two maxima, in October and February. This instrument, which has been observed for 12 months, confirms the expectation. The daily mean distillate, the distillate per hour of sunshine (Campbell Stokes) and the mean distillate for the three hours before noon, all show the same seasonal changes.

The instrument has been standardized against Gorczynski's pyrheliometer, so that the readings in c.c. of alcohol can be converted into calories. The instrument is not difficult to make or read, and it can be left in the open in all weathers. It integrates its results and requires to be read once a day in Samoa.

Four outbreaks of food-poisoning are described in which over 100 cases in all of gastro-enteritis occurred, one being fatal. In each outbreak the infecting bacteria were indistinguishable culturally and in serological behaviour from the “G” strain of B. suipestifer.

The reasons are given for following Andrewes and Neave and classifying these as B. suipestifer. (sub-group II).

Since Dick and Dick (1924) Published their method of testing the susceptibility or insusceptibility of human beings to scarlet fever various other workers have reported in vestigations which have confirmed the observations of the Dicks.