1. A comparative study has been made of the life history of two groups of rats, one of which (483 animals) was maintained on an adequate diet whilst the other (556 animals) was given a ration providing a suboptimal intake of “vitamin B”. The chief defect of the second diet was probably in respect to vitamin B1.

2. The duration of life was shortened and reproduction was adversely affected by the deficiency.

3. The examination of the post-mortem records provides clear proof of a significantly greater incidence of gastro-intestinal lesions, particularly ulcerations, in the animals on the deficient diet than in the control group.

4. The deficiency of B1 did not influence the incidence or the severity of the chronic lung infection (bronchiectasis) common in laboratory rats.

5. The incidence of all other disorders was about the same in the two groups.

6. No evidence of increased susceptibility to tumours, malignant or innocent, was shown by the animals on the deficient diet. Cancerous developments arising at the site of chronic inflammatory processes (e.g. worm cysts in the liver, caecal ulcers of long standing, etc.) were not appreciably more numerous in one group than in the other.

Mineral oil injected into the peritoneal cavity of mice tends gradually to disappear. The amount of oil recoverable after a given time depends upon its toxicity, as registered by the carcinogenicity for the skin, refractive index fall, refractivity etc. The 7th day after injection is apparently about the best time to collect the oil.

Loss of body weight of the animal is also a measure of the carcinogenicity for the skin, refractive index fall, refractivity etc. of the oil sample under test. The 3rd day after injection is apparently about the best time to record loss of body weight.

The best animal test for measuring the activity of mineral oils is the injection test, and subsequent determination of the refractive index fall.

The best physical test is to determine the refractive index and viscosity and to combine these in an empirical formula.

A combination of the two tests is the best of all.

The relative amounts of carcinogenic and dermatitic constituents responsible for the general activity can be gauged by a consideration of the viscosity.

1. The population as a whole is exposed to Brucella infection by the consumption of infected milk. This does not appear to be a very potent source of infection as relatively few clinical cases of brucellosis occur, nor are many latent infections discovered by the agglutination reaction.

2. Those exposed to contact with infected animals or meat, as are farm workers, slaughterers and butchers, run a greater risk of contracting infection. The risk is not, however, markedly increased when the contact is limited to the handling of carcasses or meat, milking or ordinary animal husbandry.

3. Members of the veterinary profession, who assist in calving and remove placentas from infected cows are exposed to the greatest risk of infection. They come in contact with the greatest natural concentration of Br. abortus through the most dangerous route, the skin. Clinical brucellosis is not common among them, but many contract latent infection. 58·3% of post-graduate and 10·8% of undergraduate veterinary students were found to have agglutinins for Br. abortus in their serum. This should be borne in mind when a diagnosis of undulant fever is considered in a member of the veterinary profession.

An account is given of two cows which were concerned in milk-borne Streptococcus outbreaks at Mørkøv (Denmark) and Doncaster (England) respectively, and. which were afterwards kept under close observation. The Danish cow excreted Str. pyogenes from the affected quarter for at least 13 months, including a dry period of about 3 months; the other animal excreted similar streptococci for about 6 weeks. In both cases there were stages when symptoms of mastitis were either not evident or not pronounced, although the milk was known to be infective.

A report is given of a milk epidemic of septic sore throat, comprising about 100 cases.

The epidemic originated from a cow with a slight degree of mastitis, produced by a Streptococcus pyogenes (Lancefield's group A).

The same Streptococcus (which we did not succeed in typing) was isolated from 74% of the patients examined and from three persons who were handling the milk.

It seems reasonable to assume that the cow was infected from the milkers. Owing to particular conditions in the distribution of the raw milk, it is possible that the milk delivered raw in the village involved on one day a massive contamination.

The epidemic is characterized as moderately severe. No case terminated fatally.

It has been found that carcinogenic tar acts upon the lymph glands of the rat in converting them into more or less pronounced haemolymph glands.