1. Outbreaks of epidemic disease are common in populations of wild animals, including species little influenced by contact with the diseases of human beings or domestic animals.

2. Such epidemics form one of the commonest factors responsible for fluctuations in numbers of wild mammals.

3. An attempt is made to summarise the available published records of such epidemics (Section II), while certain unpublished records (communicated to me by naturalists) are contained in an Appendix.

4. Little is known of the causes of these epidemics except in the cases of plague and tularaemia.

5. The fluctuations in numbers of some wild mammal populations are sufficiently regular to make the forecasting of epidemics possible. This method is already applicable to wild mice.

6. Mouse periodicities are discussed in detail, with special reference to epidemics and their causes, which are mainly obscure (Section III).

7. Development of the forecasting methods described will make possible the prediction of many other wild mammal epidemics, and render intensive pathological and epidemiological studies more practicable than they have hitherto been.

The last life table for the Administrative County of London was prepared by Mr King from the census population of 1911 and the deaths in 1910, 1911, 1912, and published in Part I of the Supplement to the 75th Annual Report of the Registrar-General, 1914. The national life tables (No. 9), prepared by Sir Alfred Watson after the census of 1921, included one for “Greater London,” the boundaries of which extend considerably beyond the County Council area and enclose the range of jurisdiction of the Metropolitan Police, so that this table is not geographically comparable with Mr King's 1911 table. The object of the present study was a comparison between the extended method of Mr King and the shorter ones of Drs Brownlee and Snow, to see whether the methods gave comparable results as regards the expectation of life, the question with which the public health worker is mainly concerned. As an example I selected the County of London (census population for 1921, deaths in 1920, 1921, and 1922) as affording, at the same time, an opportunity of making a table comparable with that which Mr King prepared for 1911. Drs Brownlee and Snow have already shown that their methods gave very satisfactory results as judged by the older life tables of this country. This paper will show that similar results have, in the main, been obtained as regards the 1921 experience.

While investigating the effects of silica dust and coal dust respectively in the production of respiratory disease in coal miners, we have been struck by the sharp contrast between silicotic coal miners in South Wales as compared with silicotic gold miners in South Africa in their respective liability to pulmonary tuberculosis. Coal miners have always been noted for their relatively low tuberculosis mortality, while gold miners and other workers in hard rock, but exempt from simultaneous exposure to coal dust, are conspicuous for their marked liability to fatal pulmonary tuberculosis in late middle age. And yet the recent findings of Cummins and Sladden (1930) and of the Medical Staff of the Welsh National Memorial Association (1930) indicate that both in the pathological, histological and chemical characters of the lungs of Welsh coal miners and in the X-ray appearances observed in long-service colliers of over forty years of age, there is nothing to distinguish them from Band gold miners suffering from silicosis except the added presence of large amounts of coal dust in the lung tissue of coal miners and their relatively low tuberculosis mortality. This contrast has been discussed by one of us (S.L.C.) in a recent paper (1931) and the suggestion made that the well-known adsorption power of finely divided carbon particles for colloidal substances might be a factor in reducing the liability of the coal miner to pulmonary tuberculosis.

The technique of detecting diphtheria bacillus carriers has found little recognition in the literature of diphtheria.

A method of detecting diphtheria carriers by single swabbings is described.

The method is somewhat elaborate but is highly efficient.

The results which may be obtained with it are discussed.

Its application in certain specific cases is briefly considered.

In the last memoir of this series (Greenwood, Topley and Wilson, 1931) we discussed at some length the modifications of the course of herd sickness effected by immunisation of entrants to the herds. Briefly, these were our conclusions: efficient artificial immunisation (the criteria of efficiency being the usual standardising methods of a laboratory) confers a considerable temporary advantage upon mice entering an infected herd. The risk of death during the period of herd life when the rate of mortality is especially high is greatly reduced, so that when one has the case of a herd or group temporarily exposed to special risks, the value of the expedient is very great. But no method of artificial immunisation we have tried will render the immunised animals impervious to the risks which their membership of the herd entails.

1. Most artificial manures are found to have some effect in increasing the iodine content of crops, particularly superphosphate.

2. Marked differences are found between the iodine contents of Samoan and New Zealand foodstuffs corresponding to the non-goitrous condition of Samoa and the partial endemicity of New Zealand.

3. Investigation of the dietaries of fifteen residential institutions showed that improvement in provision of iodine was necessary in many cases by using fish at least twice a week, raising the daily ration of milk to 1 pint per head, and employing iodised salt for table and culinary purposes.

4. Dietetic experiments indicate (i) that on a change of diet adjustment of iodine metabolism may take a considerable time, (ii) that iodised salt is most effective in promoting storage of iodine when associated with a meat diet.

5. Iodine excretion is found to decrease much more rapidly under fasting than on a diet very low in iodine.

6. Iodised salt has the effect of adjusting the excretion of goitrous adults to the normal non-goitrous value.

7. The iodine content of the blood is found to be lower than normal in cases of simple colloid and simple nodular goitre, though it may range from low to abnormally high in cases of Graves' disease. In all types of goitre the thyroid gland is low in iodine.

8. The ratio of thyroid iodine to total bodily iodine is about 12 per cent. in the case of the white rat under ordinary conditions, but the ratio is found to vary considerably with the iodine intake.

9. Great differences in the ratio of the weight of the thyroid gland to that of the whole body are found among different species of animals, the ratio being higher for the dog than for the monkey.

10. Variations in commercial samples of iodised salts are recorded and discussed.

11. Data are given in regard to the iodine and chlorine content of rainwater in different localities.

1. The occurrence of an exalted strain of rabies virus has been recorded and a definition given of virus de rue renforcé.

2. The characteristics of exalted virus have been examined in respect of incubation time, fixation rate and absence of Negri bodies.

3. An adequate classification of street virus strains has been suggested.

4. Cross-immunity experiments have been carried out and, as a result of cross-protection tests and of crossed serum reactions, identity of exalted virus with the classical strain has been established.

5. The employment of autogenous and polyvalent vaccines has been shown to be unnecessary in anti-rabies immunisation.

1. Refection occurs as a rule in rats receiving diets containing raw potato starch.

2. Rats were maintained for one year on a diet deficient in the vitamin B complex and containing raw potato starch. Two of them attained a weight of almost 300 grm. and made sustained gains at a rate of almost 4 grm. daily.

3. Rapid decline, symptoms of vitamin B1 and B2 deficiency and death were observed in these rats after their diet had been steamed.

4. Steaming under identical conditions does not alter the vitamin B (complex) content of other diets.

Since remote times man has cultivated many kinds and varieties of peas and beans as food for himself and his domestic animals, and with two notable exceptions there has apparently been little suspicion on his part that they might be potentially poisonous or deleterious. The exceptions are the bitter vetch (Ervum ervilia L.) and the vetchling Lathyrus (L. sativus, L. cicera and L. clymenum), the former of which ever since Hippocrates recorded the first known epidemic and the latter since the seventeenth century have been recognised as liable to injure farm animals and to cause in man an incurable paralysis of the legs if eaten in too large quantity as part of the daily dietary. The bitter vetch is now only of limited agricultural importance as a cattle food, but lathyrus is extensively grown in France and southern Europe chiefly as fodder for farm stock and also to some extent for human consumption. The peasants cook and eat it like other pulses and the meal mixed with wheat or barley flour is made into bread, hence in times of scarcity and dear cereals an excessive use of it has often given rise to local outbreaks of poisoning. In India and in Kabylia the peas, whole or ground and cooked in various ways, form the staple diet of large sections of the poorer classes, as they are cheap, palatable, and very nutritious, and in times of famine the increased consumption has been the cause of many recorded pandemics. Apart from famines, however, large agricultural populations in some parts of India subsist to a great extent on lathyrus peas (khesari, teora, matra) and in certain States of North-West and Central India 6 per cent. of the total inhabitants are said to be affected in consequence by paralysis of the lower limbs, and in some of the worst villages 10 per cent. or more of the adult males. The condition has always been well known under various names to physicians practising in the countries affected, but in 1873 Cantani (Naples) gave it the name Lathyrism under which it is now usually described in text-books of medicine. As very large numbers of mankind habitually consume lathyrus peas it may safely be assumed that they are innocuous when taken as a moderate part of a mixed dietary, and Buchanan states that in some Indian jails 4–6 ounces per person have been given daily for years without any bad results having been observed, while on the other hand, Grandjean and others find that when they form almost the whole dietary paralysis supervenes in 4–8 weeks. But the grain varies considerably in its content of toxic substance and the results depend partly on this, partly on the amount eaten, and probably to some extent on individual susceptibility. Men are much more liable to be affected than women, in the ratio of 10 or 12 to 1, and boys than girls. Slight cases of lathyrism show merely a certain degree of motor paralysis and spasticity in the lower limbs which may pass off. In more severe cases the paralysis comes on suddenly and may involve the bladder, rectum, and genital organs, while there may also be pains round the waist, lightning pains, loss of sensation, numbness, cramps, and prickling. All these symptoms, if present, usually clear up with the exception of the spastic paralysis which varies greatly in degree and is permanent. Chevallier (France 1841) mentions somnolence as a symptom, Brunelli, who reported eleven cases which occurred in the neighbourhood of Rome (1880), states that after each meal certain of them showed a kind of transient intoxication, and Desparanches, who described an extensive outbreak round about Blois (1829), says that convulsive movements of the limbs is the earliest symptom in some cases. It is evident therefore that the poison may affect any part of the brain and spinal cord, but that its chief and permanent effect is exercised on the motor tracts from the cortex downwards. The general health remains good, and it does not directly shorten life. Lt.-Col. McCombie Young has published a very clear analysis and explanation of the motor clinical symptoms which makes any further account of them here unnecessary, and Proust's report on an outbreak in Kabylia also gives very full details. No post-mortem examination of the nervous system in man has ever been made.

As Scotland is the only home country for which information is published on the regional distribution of the mortality from cancer according to site, it seemed of interest to examine whether a particular site, or group of sites, had any special geographical location. With this object in view the present investigation was undertaken for the period 1923–8.