1. An attempt has been made to ascertain by physiological observations on school children whether the radiant heat from a heating installation comprising electric panels suspended from the ceilings and walls of the classrooms, in a semi open-air school, was sufficient to impart adequate warmth to children while performing the ordinary curriculum of an elementary school.

2. During identical cold weather conditions, observations were made on children in two schools in the same area, the one heated by electric ceiling and wall panels and the other, the control school, heated by hot-water radiators and pipes.

3. The children in classrooms heated by radiant heat from electric ceiling and wall panels were found to be attempting to perform ordinary elementary school work under conditions of chilling incompatible with comfort and efficiency, and without such compensating factors as frequent exercise and controlled nutrition, neither of which are possible in such a school.

4. The observations made on the children in the semi open-air electric-panel heated school, the air temperatures and cooling powers encountered in the classrooms, and the control observations made in the hot-water heated school under similar weather conditions prove that the radiant heat emitted from the electric ceiling and wall panels was insufficient to impart adequate warmth to the children, and that the heating system as at present installed and controlled, is unable adequately to cope with such cold conditions as are commonly met with during the winter months of the year.

1. A preliminary survey of the bacterial flora of some different types of slaughterhouse indicates the sources from which heaviest contamination with bacteria is likely to occur.

2. Cleaner working conditions are shown to lead to a diminution in the numbers of organisms present in the air, swabbing water, etc., and in a reduction in the proportion of certain types of organism.

1. Examination of the “slime” obtained on lean beef stored at temperatures just above zero Centigrade has shown it to be composed chiefly of organisms of the Achromobacter group.

2. A study of about 120 strains of these organisms has been carried out and the characteristics of typical strains are given in detail.

3. Data of the rate of growth of these organisms on meat and in broth are given.

4. The dependence of the “storage life” of the meat on the initial bacterial load is shown.

A small quantity of a culture of aerotactic organisms, especially Polytomauvella, is placed in a narrow tube and a column of water superimposed. The organisms aggregate and rise in blanket-like formation at a speed which is inversely proportional to the amount of oxygen in solution. If nitrates or nitrites are present they slow down the rate of climb. The climb must be accelerated by the presence of substances and organisms with a pronounced affinity for oxygen and slowed down by the presence of photosynthetic organisms. The reaction may therefore be of use in estimating the quality of sewage effluents or pollution in rivers, having possibly some advantages over the present routine methods of chemical estimation. A tentative grading scheme for the quality of such waters is proposed.

Six strains of an organism associated with and apparently etiologically related to clinical cases of dysentery have been described. Five of these strains were isolated from cases in a town in Lancashire and the other from a case in Nigeria.

These strains seem to be identical with the Newcastle dysentery bacillus described by Clayton and Warren except for the apparently constant difference in the action on mannite. Their relationship to the Flexner group of dysentery bacilli has been discussed.

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.

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.

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.

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.

It is best to begin with antibodies which conform to their original definition as new serological properties attributable to an antigenic stimulus.

Their origin is still disputed. They are often regarded as cellular secretions due to adsorption or ingestion of antigen. For my part, I consider that they are formed in the plasma by filtration through capillary endothelium which has adsorbed antigen.

The precise specificity which characterises many antibodies is difficult to explain. I have suggested that it may be due to an interplay of reactions between the dextro- and laevo-rotatory forms of particular combining affinities.

But antibodies are not always the exact counterparts of their antigens. I have discussed some of the possible reasons why animal idiosyncrasies may be responsible for irregular results. A defective yield may also be due to the antigen, which may be present in a masked condition.

It is often taken for granted that the characters of the antibodies found in the serum of an actively immunised animal are identical with those actually present in the animal's circulation. I have given reasons for thinking that this assumption is frequently erroneous.

Coming now to the more elastic conceptions of “antibodies,” which relate to properties not attributable to an antigenic stimulus, the part played by alexin in the circulation of the normal animal has first to be considered. It is not a distinctive chemical entity, nor is it simply a chemico-physical condition of the plasma; it is a complex of chemical and physical factors which defy analysis. The dual mechanism represented in vitro between alexin and “immune body” does not afford a true picture of alexin's activities in vivo.

The humoral factors in natural resistance are too complex to be regarded as a dual mechanism. The difference between susceptibility and resistance often depends on that precise sequence of events in the plasma's activities which is peculiar to the species or even to the individual.

Acquired immunity is a reconstruction of the normal mechanism, with the emergence of a definitely new property. It is not simply the introduction of a new antibody but involves also utilisation, with readjustment, of the complex biological conditions normally present. As a result of the antigenic stimulus: (1) antibodies may be formed which are the precise mirrors of their antigens; (2) by a similar but less precise mechanism, antibodies may arise which are not the exact counterpart of any particular antigen; (3) the antigenic stimulus may lead to complex humoral changes which are not identifiable as antibodies.

Current opinions on immunological principles, as expressed by well known authorities, exhibit divergencies which cannot be satisfactorily reconciled with each other. There is, however, general recognition that the present status of knowledge is highly deficient. Though the time is not yet ripe for anything like a finally satisfactory reconstruction of these principles, efforts in this direction are needed, with readjustment of the old ideas by the aid of hypotheses about what is going on in the living body.

1. Experience of 4½ years of intravenously administered scarlatinal antitoxin, in 1204 cases, confirms the tentative conclusions reached in 1928, viz. that the acute stage of the disease can generally be arrested in 12–24 hours, complications almost wholly prevented, and the period of morbidity reduced to a little over a fortnight.

2. These effects were obtained in hospital wards where over 50 per cent, of the cases, generally about 75 per cent, and including all the worst, were so treated, and it is possible that the reduction of mass infection obtained in the wards by this means is an essential condition for obtaining such results. Under such conditions relapses and cross-infections were very rare.

3. Some evidence was obtained that intravenous antitoxin administered in the acute stage of scarlet fever largely prevents the onset of septic complications, including the late septic type itself, scarlatina anginosa; and that it may be of striking benefit in the treatment of the septic type, even at a late stage.

4. The importance of proved clinical potency and freedom from dangerous reactions of each individual batch of serum to be employed, is stressed.

5. Indications and contra-indications are stated.

6. Certain precautions and details of technique are recommended.