1. The outbreak was one of bacterial food poisoning due to the consumption of infected milk.

2. The casual organism was B. enteritidis of Gaertner (Dublin).

3. A case of gastro-enteritis occured in an employee in the institution some days previously. This man's serum possessed agglutinins for for Gaertner'sbacillus, but the organism was not isolated from a specimen of his faeces taken 44 days after this attack.

4. This employee is supposed to have been the source of the organism which infected the milk. Two hypotheses are put forward to explain the mechanism of infection.

5. Servants who took the infected milk in their tea escaped infection. The milk was added to the tea in bulk and the experiments described satisfactoryily account for their escape.

The method in which the mortality in childhood varies from age to age is a matter of very considerable interest. With each increase of unhygienic circumstances the death-rate among infants is well known to rise and it is commonly taken as a criterion of the measure of the unheathiness of the environment. In a rough way this is quite true but it is not the only criterion, any year of life might equally well be taken. The investigation in this note is based on a tabulation mande from the data published by the Registrar-General of England for the decade 1891–1900. In order tp make the statistics as homogeneous as possible the registration districts have been grouped accroding to the infantile mortalites, intervals of ten being taken in the unit. Thus those districts with death-rates between 80 and 90 have had their populations and deaths grouped togeather, those between 90 and 100 likewise and so on.

Contradictory opinions are at present held on the subject of bacterial standards of purity of water in India. My recent researches tend to throw some light on some of the causes of this divergence of opinion. The presence of frogs in water has been found to be responsible for an increase in faecal bacilli which, though negligible in the case of large bodies of water, is apt to be misleading in the case of waters of great purity. Stasis in reservoirs and passage through pipes may be responsible for a considerable increase in faecal bacilli in water, so that a mere increase in the number of faecal bacilli in a reservoir or pipe water does not necessarily indicate faecal contamination but may simply be due to stasis in reservoirs or flow through pipes. These findings lead to two conclusions of importance in regard to the bacteriological examination of water: (1) in testing for the bacterial efficiency of sand filters, samples should be collected from the filter well and not from the clear water reservoir where water is usually stagnant for some hours; (2) in interpreting the results of the examination of pipe waters the possibility of an increase of B. coli having occurred through multiplication in the pipes should always be borne in mind before inferring that such increase is indicative of faecal contamination or leakage in the mains.

The year 1921 was characterised by prolonged high temperatures and was one of great difficulty for the milk industry. It is, therefore, of interest to study the resultes of the bacteriological examination, and the keeping qualities of samples of Grade “A” (certified) milk which were examined during the period January 1st to December30th, 1921.

It has been found that the reductase test gives a considerably higher estimate of the number of organisms present in some milk samples than the plate method. This, however, is doubtless due to the fact that many colonies obtained by plating do not arise from a single cell but from chains of cocci and bacilli. Again the plate method takes no account of the anaerobic bacteria present in the milk.

When there are more than 100,000 organisms per cubic centimetre in the milk it would seem that the reductase test gives just as accurate an estimate as the plate method.

In its present form, however, the test would not be of service in grading of milk according to the bacterial standards now suggested.

1. The course of elimination of passive immunity in rabbits injected intravenously with diphtheria antitoxin obtained from a horse, consists of three phases:

(a) an initial loss of 50 per cent, occurring within the first 24 hours;

(6) a gradual constant percentage loss of approximately 25 per cent, from day to day, lasting 6–7 days;

(c) a rapidly accelerated loss of 50 per cent, or more per day after the seventh or eighth day.

2. In rabbits sensitised with small doses of horse serum the same three phases are seen, but

(a) while the initial loss remains the same

(b) the gradual constant percentage loss is of the same magnitude, but lasts only two or three days;

(c) the rapidly accelerated loss occurs after the third or fourth day and over 90 per cent, of the antitoxin present is lost within 24 hours.

3. Possible explanations of the three phases are:

(a) initial loss due either to precipitin to horse serum normally present in rabbits or to saturation of or adsorption to the tissues;

(b) a phase independent of precipitin action;

(c) accelerated loss due to formation of precipitin commencing seven or eight days after injection of horse serum in normal rabbits and three or four days after injection in sensitised rabbits.

The author was recently asked to advise the Boards of two Dublin hospitals as regards the cleanliness and general suitability of the milk supplied to them. In order to find out exactly the present position of the milk supply, it was decided to investigate bacteriologically the influence of the various factors at work from the time the milk left the cows till its delivery at the hospitals.

1. The growth of diphtheria bacilli in suger-free pure casein digest broth may be accelerated by the addition of dilute nitric, acetic and lactic acids, and delayed by certain monobasic fatty acids.

2. The limiting acid zone for toxic and non-toxic varieties is unaffected by initial dilute acidifications by several acids, but incresaed by the addition of citric acid.

3. The time periods and intensity of the reaction changes produced by diphtheria bacilli growing in a sugar-free casein digest medium are altered by the addition of certain acids. Toxic strains produce earlier and more progressive alkalinity when dilute acetic or nitric acid is included in the medium: and later and lessened alkalinity in the presence of butyric, formic, and propionic acids. Certain other typical acids do not exert any obvious action. Non-toxic strains are less affected by the selected acids, although butyric acid generally retards reaction changes.

4. The time required for virulence testing is decreased, and the potency of the bacillus under examination is more evident when 1/200 η acetic or nitric acid is added to the culture medium. Acidified casein digest plus peptone broth yields practically the same results as acidified fermented veal peptone infusion. The acidification does not affect the metabolism of non-toxic strains.

5. The disadvantages of unfermented meat infusions and the ascribed harmful effects of the fermentation products in fermented meat broths, may perhaps be avoided by the substitution of casein digest peptone medium. The advantages of the starting action of the glucose may be retained by adding acetic or nitric acid to the casein digest.

6. Individual strains of diphtheria bacilli differ considerably in their capacity of altering the reaction of culture media, and in their toxic potency. It does not seem permissible to apply to newly isolated organisms all the published results obtained from cultures that have been repeatedly subcultured and established as toxin producers in nutrient bouillon. As a presumptive test in the virulence testing of bacilli just transferred from human tissues to artificial culture media the tendency of non-toxic strains to produce early formation of alkali in adequately buffered and adjusted unfermented veal broth may be thought worthy of extended trial.

(1) Two types of B. coli are met with in urinary infections-haemolytic and non-haemolytic. Haemolytic colon bacilli are much commoner in infections in the male (72 per cent.) and non-haemolytic in the female (70 percent).

(2) It was very uncommon to obtain both these types of colon bacilli associated in any particular case, or for a haemolytic infection to be followed by a non-haemolytic, or vice versa.

(3) No evidence was obtained of direct relationship between the urinary haemolytic colon bacilli and those of the intestinal tract.

(4) The haemolytic urinary colon bacilli were readily grouped by appropriate colon anti-sera, but this result was much less common with the non-haemolytic strains.

(5) Culture media, in our experience, were of little value in the grouping of colon bacilli.

(6) A haemolytic colon bacillus has not been cultivated by us from the blood stream in the human subject.

(7) Two cases of acute infection were met with, caused by strongly haemolytic, but atypical, colon bacilli.

(8) The blood sera from “normal” cases and from coli infections were tested for the presence of coli agglutinins. Several coli antigens were employed. A very much higher percentage of positive findings were obtained with coli cases.

(9) Living colon bacilli, haemolytic and non-haemolytic, can be inoculated into rabbits in small or massive doses without serious ill-effect-in fact these animals have a remarkable tolerance for these organisms. No marked anaemia was produced by the injection of living or dead bacilli or filtered broth cultures. Agglutinins and precipitins were rapidly formed with the haemolytic strains.

(10) Eenal infections in rabbits were not obtained by the injection intravenously of various strains of urinary and faecal colon bacilli.

(11) Saturation agglutinin experiments showed in the majority of instances that colon anti-sera, made from non-haemolytic strains, are not desaturated by non-haemolytic colon bacilli other than autogenous strains, while with the urinary haemolytic colon anti-sera and haemolytic colon bacilli a much wider range of action is obtained.

(12) Precipitins and complement fixation reactions were readily obtained with coli rabbit anti-sera and filtered beef broth coli cultures.

(13) The action of No. 220 soluble mercurochrome was investigated in the treatment of coli infections of the urinary tract. This substance was found to be of definite therapeutic value, especially when employed in conjunction with vaccine therapy.