1. Methods for the estimation of iodine in natural products are described.

2. Common sea weeds on the Pacific coast of Otago have an iodine content of the same order as similar species on the Pacific coast of British Columbia.

3. In Cystophora retroflexa, which contains over 0·1 per cent, of iodine, 70–80 per cent, of the iodine appears to be in inorganic or loosely bound combination. Precipitation and colour tests indicate that di-iodotyrosine is also present.

4. Observations are recorded of the iodine content of kelp-feeding and other fish.

5. Administration of anaesthetics produces fluctuations in the concentration of blood iodine in rabbits, the effect persisting after removal of the thyroid gland. Experiments in vitro suggest that only in the case of inorganic iodine could a redistribution of iodine between tissues and serum be brought about by the direct action of anaesthetics.

6. New Zealand cabbage possesses goitrigenous properties for rabbits but in a much smaller degree than American cabbage.

7. The urinary excretion of Samoans is compared with that of inhabitants of Christchurch Mental Hospital.

8. The incidence and course of development of goitre at Christchurch Mental Hospital is discussed.

9. Values are given for the iodine content of Otago pigs' thyroids.

Pellagra is a comparatively modern disease. The first account of it dates from 1735 when under the name mal de la rosa it was very fully described by Gaspar Casal who at that time practised at Oviedo and found it endemic among the Asturian peasantry. In Lombardy it was recognised about 1730 and only much later (1771) was systematically described by Frapolli as pellagra (rough skin), but Strambio, who was physician to a special hospital for pellagrins at Legnano, states (1784) that many of his patients told him that their fathers and grandfathers had suffered from the disease. Early in the nineteenth century it was comparatively common in Gascony and about 1836 it was beginning to be recognised in Roumania. In the United States sporadic cases seem to have been noticed in 1864, and since 1907 it has increased to an extent which has seriously disquieted the public health authorities. In Egypt, Turkey, Mexico, the Balkans, Brazil, the West Indies and other countries it is common and well known. Wherever it has appeared endemically it has followed on the introduction of maize as a field-crop and its adoption (by the rural population especially) as a chief and staple article of diet.

Tyzzer (1917), who described an epidemic that had appeared in his mouse colony, named the causative organism Bacillus piliformis, giving an inclusive description of its behaviour and morphology. Both natural and experimental infections were studied. The high susceptibility of the Japanese waltzers as contrasted with the relative immunity of the common mice suggests that the disease susceptibility may be linked with the waltzing factor.

The following study completes the examination of the data derived from certain physical and physiological measurings of adolescent boys at the Manchester Grammar School, taken during the last ten years with a view to enquiring whether any definite relationship could be discovered between such measurings, considered singly or in combination, and either general scholasticattainments or special aptitudes in school sports and games. If such relationship, indicating either general or particular aspects of health and vitality, could be discovered, then, although spontaneity of choice in classroomand playing-fields should always be jealously guarded, yet the cause of many failures might be revealed and such innate energy as the boy may possess be directed into more appropriate channels.

An investigation has been made into sporadic Salmonella infections. The most prevalent infecting organisms have been found to be Salmonella types aertrycke and thompson. Infections due to S. dublin, S. suipestifer (both European and American types) have also been encountered. The striking features of the investigation have been the number of individual cases and the lack of definite evidence of the source of infection.

1. A photo-electric cell was used to measure photometrically the opacity of cultures of Salmonella gallinarum growing in bouillon.

2. The opacity of a culture was defined as the number of 24-hour-old bacteria which when suspended in the same type of bouillon as those under investigation would absorb the same amount of light. Seven experiments were made to compare the opacities of growing cultures with their actual numbers throughout the first 24 hours of growth. An additional experiment was made to find directly the numbers of bacteria of different ages which would absorb the same amount of light.

3. The ratio between opacity and number was greatest at about 3 hours, decreasing to unity at about 7 hours; the optical behaviour of cultures 7 hours old was thus the same as of cultures 24 hours old. It is possible from the results that the ratio decreased to a minimum at about 9 hours, thereafter again rising to unity. The value of the greatest ratio was greater as the inoculum was less. The mean greatest ratio was 4·6, the mean time being 3 hours. This means that it would take about 4·6 times as many 24-hour-old bacteria as 3-hour bacteria to absorb the same amount of light.

4. It was shown that the variation in the opacity-number ratio was in all likelihood due to changes in the size of the organism during growth.

5. The results suggest that the opacity curves give a truer picture of actual growth than the ordinary growth curves, since the cells change in size during growth.

Enteric fever in British Guiana, according to official reports, would not appear to be excessively common: the number of notifications for the whole Colony during the years 1930 and 1931 was 244 and 250 respectively on a population of 310,000.

The few observers who have studied this disease in the Colony have all insisted on its sporadic character. Rowland (1910) has clearly illustrated this peculiarity with a series of spot maps showing the distribution of enteric in Georgetown from 1909 to 1913.

The Salmonella group contains the organisms which are mainly responsible for outbreaks of food poisoning and the possibility of the production by these strains of bodies which are toxic, or which act as gastro-intestinal irritants, when administered by the oral route, is of practical as well as theoretical interest. This is especially the case if it can be shown that these irritant substances are heat resistant.

The isolation of fusiform bacilli from typical tropical ulcer is described and an account is given of the motility and staining properties of the organisms cultivated.

Experimental inoculations, both in man and animals, are recorded in tabular form and the results of the investigation discussed.

1. 1000 urinary and 500 faecal cultures of coliform bacteria were studied by means of the methyl-red, citrate and indol tests and also by their fermentation reactions upon saccharose and dulcite.

2. 8 per cent, of the faecal strains and 52 per cent, of the urinary strains were of the aerogenes type, i.e. methyl-red negative and citrate positive. Indol was produced in 94 per cent, and 43 per cent, of cases respectively.

3. This would suggest additional evidence that the coli group are quickly outnumbered by the aerogenes group once they leave the faeces, and also that the presence of the aerogenes type is not confined even in large numbers to an extra-corporeal habitat.

4. In water bacteriology the constancy or change in the relative proportions of coli and aerogenes strains present is the goal at which to aim. The aerogenes variety cannot of itself be regarded as non-excretal or even non-faecal.

5. From a sanitary standpoint, the classification of coliform bacteria by means of the methyl-red and citrate tests cannot be regarded as entirely free from error so long as (a) the aerogenes strains are found in faeces, in however small numbers, (b) these strains occur as the predominant type in urine, and (c) intermediate strains are found in the faeces, urine, soil and water.

6. The principal value of these tests lies in their comparative specificity in identifying B. coli of immediate faecal origin. The presence of such an organism, interpreted together with the indol test, may be said to suggest dangerous faecal pollution if found prominently in a water sample. The presence of other types identified by the same tests cannot be regarded as having the same significant value in regard to a negative opinion.

7. A plea is made for a further study of coliform bacteria by means of the tests described in relation to the biological behaviour of the bacteria under different environmental conditions.

1. A systematic study has been made of 165 Brucella strains from different parts of the world, and a less intensive study, comprising only the H2S formation, dye sensitivity, and agglutinin-absorption tests, of a special group of 156 strains from the north-east, east, and south-east of France.

2. For purposes of differentiation little weight can be attached to the use of morphological appearances, abundance of growth in culture, pigment formation, the appearance of crystals in the medium, the production of alkali in peptone water, or the utilisation of glucose.

3. The presence of 5–10 per cent, of carbon dioxide in the atmosphere is essential for the growth of most freshly isolated bovine abortus strains. This concentration frequently favours the growth of melitensis, though not of porcine abortus, strains. A concentration of 40 per cent. CO2 almost invariably inhibits to some extent the growth of melitensis and porcine abortus strains, and frequently inhibits the growth of bovine abortus strains. It may be concluded that, while the inhibition of growth of a given strain by 40 per cent. CO2 cannot be considered of differential value, the fact that growth in 40 per cent. CO2 is as good as, or better than, that in air is definitely in favour of its being of bovine abortus type, while the occurrence of growth in 10–40 per cent. CO2 but not in air almost certainly indicates that the strain belongs to this type.

4. Most bovine abortus, para-abortus, and American porcine abortus strains produce H2S freely for 3 or 4 days, while melitensis, paramelitensis, and Danish porcine abortus strains fail to produce any, or more than a small quantity on the first day only. Though the failure of a given strain to produce H2S cannot be regarded as indicating that it is of melitensis, paramelitensis, or Danish porcine abortus type, the definite production of H2S can be considered as very strong evidence that it is of bovine abortus or American porcine abortus type.

5. The dye sensitivity method, introduced by Huddleson, is of very real value in differentiation, and is the only certain method available for distinguishing between the bovine and porcine abortus types. By its means it is possible to divide Brucella strains into three main groups—bovine abortus and para-abortus, porcine abortus, and melitensis and paramelitensis. Not all strains, however, within a given group behave alike, and a number of sub-groups can be established on the basis of special sensitivity to one or more dyes. The method not infrequently yields results that demand considerable experience in their interpretation, and it cannot always be relied upon for the correct typing of individual strains.

6. The thermo-agglutination test is one of the simplest methods of detecting antigenic roughness. Any strain that fails to react negatively to this test is unsuitable for the production of smooth antiserum or for use in routine diagnostic agglutination work.

7. The agglutinin-absorption method, performed by a strictly quantitative technique, enables a differentiation to be made between bovine and porcine abortus strains on the one hand, and melitensis strains on the other, provided that smooth strains are employed both for the preparation of antisera and for absorption. The use of direct agglutination by monospecific abortus and melitensis sera affords a rapid and accurate means of typing individual strains, and may prove of value in the examination of strains which, while partly rough and unsuitable for absorption experiments, still retain sufficient smooth antigen to be agglutinated by one or other serum. It is also of great service in the detection of mixed strains. Both methods yield identical results.

8. In the examination of the main group of strains the serological method proved more valuable than any other method in the correct allocation of individual strains, and the results agreed closely with those afforded by the dye method. In the examination, however, of the special group of strains from the north-east, east, and south-east of France, there was frequently a marked disagreement between the results of the H2S and dye tests on the one hand, and the serological method on the other, the chief divergence being that a number of strains reacting by the former methods as melitensis behaved serologically like abortus. It appears as if, in this particular area of France, strains occur having the metabolic properties of melitensis and the antigenic constitution of abortus.

9. A study of the main group of strains by the various methods enumerated enabled them to be classified into the following groups: (a) bovine abortus with five sub-groups, (b) porcine abortus with two sub-groups, (c) melitensis with two sub-groups, (d) para-abortus with two sub-groups, and (e) paramelitensis.

10. A study of the special group of strains from the eastern districts of France revealed the presence of ten sub-groups. Since it is rather doubtful to what main group many of the strains belong, they have been classified according to the host from which they were isolated.

For the present it may safely be stated that on growing grass, bovine B. tuberculosis remain alive and virulent, for a period of at least 49 days in summer, in the south of England. Simultaneously with the experiments described above, a feeding experiment on guinea-pigs has been carried out, to discover whether the bacilli, proved to be infective for these animals by inoculation are, after exposure on grass for varying times, capable of setting up infection by the alimentary route. For this purpose a number of colonies of a dozen guinea-pigs each is being fed on grass at increasing intervals after the time of infection. These experiments, which are in progress, are it is hoped preliminary to the feeding of calves on similarly infected pasture.

In the preceding paper (1933) I have recorded the results of an investigation on typhoid-paratyphoid agglutinins in a random sample of the normal population of British Guiana. It has been shown what a serious cause of error these “natural” agglutinins may represent in the carrying out of routine serological work in certain countries.

In this paper a short account is given of the application of photo-electric methods to bacteriology. Although such methods are now well established, and have been used in colorimetry and nephelometry for some years, they have not received the attention they deserve. The apparatus required, apart from the cell, will be found in any well-equipped laboratory; and their simplicity, as well as the elimination of personal errors, should assure the use of such methods in all experiments involving the measurement of colour intensity or turbidity of fluids.

The results obtained show:

1. The limits of precipitation of Felton antibody with solid ammonium sulphate in several sera; the effect on these limits of the addition of purified Felton antibody and the removal of tricresol from the serum.

2. That within these limits of precipitation small fractions can be obtained which differ from each other in their ratio of antibody to protein.

3. That the purity of such fractions throughout a given serum may be reduced by the addition of purified Pneumococcus antibody to the serum, and apparently increased by the addition of tricresol.

4. That the distribution of antibody in serum taken at intervals from a horse during immunisation changes progressively.

5. Differences in the distribution of the two antibodies in serum from a horse immunised to both Pneumococcus type I and diphtheria toxin.

Since Anderson, Happold, McLeod and Thomson (1931) described their division of the varieties of Corynebacterium diphtheriae into three groups—gravis, intermediate and mitis—and submitted correlations with clinical types of diphtheria, several workers have published results of investigations which, for the most part, are against such a hard and fast classification.

The fatty infiltration of the liver which follows the ingestion of medicinal liquid paraffin and many other varieties of mineral oils is more prevalent among females than among males, and is more prevalent among pigmented eye animals than among albino eye animals. When access to the oil lasts for about 30 weeks some 40 per cent, of pigmented eye females and 20 per cent. of the albino eye males may show the condition.

It is the intermediate products, lubricating oils, obtained by distillation of a crude mineral oil which contain the bulk of the constituents which lead to fatty infiltration of the liver, while it is the so-called “spirits” and the residues left in the still which tend to lead to excessive hyaline degeneration of the organs in general. There is evidence to show that fatty infiltration of the liver and hyaline degeneration of the organs are mutually antagonistic, but there is little evidence to show that either condition is directly related to the cancerous process.

(1) The energy cost of static effort.

From previous work it appears that the metabolic cost of maintaining a given tension varies directly as the load, provided no new muscles are brought into play as the result of fatigue or local strain. There is conflict of opinion as to the relation of cost to tension; some workers find a linear relation, while others find a non-linear one.

In the present observations contractions, which were virtually isometric, were made against a powerful spring, while in a standing position.

With constant tension the oxygen cost per contraction varied directly as the duration of the contraction. With constant time and increasing tension the oxygen cost increased more rapidly than the tension.

The duration of contraction varied from ½ to 30 sec., and the tension from 30 to 165 Ib. Over the whole range the oxygen cost per contraction is adequately described by the equation

Q = T1·37 (0·0117 + 0·01090t),

where Q is the oxygen cost per contraction, T is the tension, and t is the duration of contraction.

(2) The effect of static effort on the respiration.

As a measure of hyper-ventilation the ratio of ventilation to oxygen intake is used. It is shown that in dynamic work this ratio falls below the resting value, whereas in static effort of whatever severity the ratio increases considerably above the resting value if the effort is sufficiently prolonged. The rise in the ventilation ratio runs parallel with the feelings of strain which are associated with static effort. Pain causes such a rise in the ratio, and the rise which occurs in static effort is ascribed to the influence of painful sensations of strain.

Observations were made in which the posture alternated between sitting and standing every 40 sec. The change of posture altered the distribution of the strain, and thus the subjective sensations were not so marked as in the experiments with posture unchanged. In consequence of the postural change the ventilation ratio did not rise sensibly above the resting value, and the maximum strength of pull was increased by 6–16 per cent.