In December, 1920, Capt. F.C. Minett, R.A.V.C., of the Royal Army Veterinary School, Aldershot, published an account of diphtheria bacilli isolated by him from eleven horses and one mule. He states that during the last year of the War and for some months after the Armistice the laboratory at the Army Veterinary School received for examination numerous specimens of pus derived chiefly from suspected cases of ulcerative lymphangitis; a condition in horses in which swelling of the lower parts of a limb or limbs is accompanied by abscess formation followed by ulceration. From this material he collected and investigated a number of diphtheroid strains including the bacillus of Preisz-Nocard and in the course of his inquiry discovered twelve strains of the diphtheria bacillus.

In a previous communication (1921) experiments have been described showing the effect produced by continuously adding normal mice to a cage, the population of which is infected with bacilli of the group which includes B. gaertner and B. suipestifer. It was seen that under these circumstances the spread of infection progresses in a series of epidemic waves, and that the survival-time of any batch of mice varies according to the period at which they are introduced to the cage. It was further shown that, if such regular and continuous addition of susceptible animals be persisted in over long periods of time, all the micewill eventually succumb, while, if the addition of new individuals be discontinued, the epidemic will eventually subside, leaving a proportion of survivors who may remain in apparently good health over a considerable period.

In a previous communication one of us showed that certain strains of B.typhosus presented marked serological differences. The experiments, to which we now propose to make further reference, were conducted in the following manner.

The following paper contains a study of the results of bacteriological examinations of samples of Grade “A” (Certified) milk, some of which were 24 hours old and others 30 hours old at the time of examination. This work was started in 1916 and is still being carried on. Some of the results have already been published. For purposes of comparison, these results, together with further series, are included in the present paper.

The work contained in the following paper demonstrates that valuable evidence of the relative incidence of bovine and human tuberculosis may probably be obtained by a careful record of the chances of contact infection in each case.

The material dealt with was derived from a central clinic in a large industrial Country Borough(Newport, Mon.) and from a series of smaller clinics. Two of the latter were in industrial (coal and iron) districts and three in small country towns containing semi-urban and rural populations.

Those who have studied the literature of Bacillus coli infections of the urinary tract, over a period of many years, must be fully conscious that the methods employed in such investigations have been on very similar lines. Bacilli isolated from the urine have been classified on the result of various cultural reactions of which the fermentation of cane sugar anddulcitol appears to occupy the most important position. Animals have been inoculated with various strains of urinary coli, while similar inoculation experiments have been made on animals before and after a mechanical injury to one or both kidneys had been produced.

In a previous paper it was shown that of the empty milk churns which were examined, 56 per cent, were totally unfit for use, as they contained very large numbers of bacteria and lactose fermenting organisms in high proportion. Table I (1) is taken from this paper and gives the number of bacteria per 1 c.c. of washings with sterile saline solution. These churns were taken at random on a station platform, their origin being unknown.

From the foregoing experiments, it may be assumed:

(1) That given favourable conditions, such as a direct current of air through a building, organisms derived from animals, their fodder or environment, may be disseminated over distances up to 150 feet from the building.

(2) That B. welchii is frequently present in the dust and dirt of buildings in which horses and small laboratory animals (guinea-pigs and rabbits) are housed, and

(3) That under suitable conditions, spore-bearing anaerobes such as B.welchii, may be carried with infected dust from such buildings, for a distance of at least 90 feet, and probably considerably further.

(a) Primary Stimulus. In animals possessing no normal antitoxin a single injection of toxin either “attenuated” or under cover of antitoxin, whether injected previously or at the same time or present in the form of passive immunity maternally transmitted, is followed by a latent period of about three weeks, and the maximum immunity is reached in about eight weeks.

(b) Secondary Stimulus. In immune animals, whether naturally immune or artificially immunised, a single injection of toxin or of a toxin-antitoxin mixture is followed by a latent period of about four days and the maximum immunity is reached in about ten days; the great and rapid immunity response to the secondary stimulus offers a striking contrast to the small and gradual response to the primary stimulus.

(c) Intermediate Stimulus. In partially immune animals the response to an injection of toxin is in magnitude and rapidity of a character intermediate between the responses following a primary and a secondary stimulus.