1. Groups of young rats have been fed for periods up to one year on a diet consisting of raw or sterilized milk, with a biscuit made from white flour, to which were added supplements of iron, copper and manganese salts. By this method two samples of commercially sterilized milks, prepared by two different processes, have been compared with the corresponding raw milks drawn from the same bulk supplies.

2. At the end of one year the weights of the groups receiving sterilized milks were about 10 per cent, lower than those of the animals receiving raw milks from the same bulk supplies. This finding is similar to that of Drummond (1933) in a study of the relative values of raw and pasteurized milks by the same methods. It is however in considerable contrast to that of Mattick and Golding (1931) who in comparable experiments found that sterilized milk did not adequately support growth.

3. Animals receiving sterilized milks remained in excellent condition throughout the experiment and they could not be differentiated as regards general health from those which received the raw milks.

4. Adequate reproduction occurred on the raw milks, but no litters were reared. Reproduction was less good on the sterilized milks and, as with the raw milks, no litters were reared.

5. The results with the milk prepared by one sterilization process seemed on the whole better than those from the other; but the evidence was not sufficiently conclusive to make this deduction certain.

A comparison of Webster's selected, genetically heterogeneous resistant and non-resistant mice (here called mice A and B) has been made with two pure lines of mice (here called D and E) which were discovered to be similarly resistant and non-resistant to certain bacterial infections. In both cases, resistance and non-resistance were very marked characteristics when the infection in question was intraperitoneal inoculation with an organism of the Salmonella group; when the infective test dose consisted of intraperitoneal inoculations with a Pasteurella or Pneumococcus or of intracranial inoculation with the virus of louping-ill, these characteristics were no longer maintained, there being no certain difference in the mortality rates of the four mice lines.

In an attempt to discover some factor which might help to explain the very notable differences in resistance to Salmonella infection which exist between these mouse lines, the normal antibody content of their sera was investigated.

In experiments modelled on the bactericidal test, but possibly assessing rather the power of the sera to inhibit growth, it has been shown that both resistant races A and D possess this power to a much greater extent than do the two non-resistant races B and E.

A further examination was the estimation of the antibody response after inoculation with killed Salmonella vaccine. So far as mouse numbers permit of judgment it was seen that the resistant race A produced a higher mean titre of H agglutinin than the non-resistant races B and E.

1. Normal human sera have no natural bactericidins active against strains of gonococci.

2. Normal sera from eleven other mammalian species showed a powerful bactericidal action against various strains of gonococci.

3. The serological heterogeneity of the gonococcus group revealed by agglutination and complement fixation is again demonstrated in the bactericidal test with immune antiserum.

4. There is a steady rise in the incidence of positive bactericidal action in the sera of patients following the progress of infection with the gonococcus.

5. The probable significance of these bactericidins, natural and immune, discussed.

Acknowledgments. I wish to express my gratitude to Dr Ledingham for the facilities for work granted me at the Lister Institute and to Dr Schiitze for his kind help and critical advice during the progress of this investigation.

Salmonella infection is fairly frequent in some animals, but is not very common in sheep. Moreover, food poisoning in man associated with mutton is comparatively rare. It is true that S. typhi-murium is sometimes referred to as the “mutton type” of Salmonella (Schütze, 1920; Lovell, 1932 b).

The filtration end-point of 0·2μ leads us to assign according to Elford (1933) a value 100—150 mμ. for the particle diameter of the virus of rabies. This figure we have previously reported in Ann. Report Med. Res. Council (1934) and also in a discussion held by the Royal Society of Medicine (Galloway, 1936). Recently the Japanese workers, Yaoi et al. (1936), using similar graded collodion membranes (gradocol) and the same general technique as employed in the present experiments, have studied independently another strain of “fixed” rabies virus “Fukuoka”. Their stock filtrates appear to have been more potent than ours, their figures for the limiting infective dilution being 10–3 to 10–4. The incubation period in rabbits inoculated with the “Fukuoka” strain is also shorter than in the case of rabbits inoculated with Pasteur Institute (Paris) strain. Even so, they find exactly the same value for the filtration end-point 0·2 μ as found by us for the Pasteur strain, thus indicating the particle size of these two “fixed” strains of rabies virus to be the same.

1. Some improvements in the determination of small quantities of iodine in biological substances are described.

2. The thesis that a low iodine intake is prerequisite for goitre production is supported.

3. A survey of determinations by various authors of the daily urinary iodine excretion in goitrous and non-goitrous regions leads to the conclusion that the critical level of iodine intake sufficient to suppress goitre is between 120 and 160γ per day.

4. Determinations of urinary iodine excretion in New Zealand and in the non-goitrous islands of Samoa are presented which show that in the parts of New Zealand investigated the iodine intake is at a low or goitrous level.

5. The result in New Plymouth, Taranaki, shows that a high content of iodine in the soil does not necessarily assure an adequate iodine intake.

6. The progress of prophylaxis by iodised salt in New Zealand is reviewed, and from consumption data it is concluded that iodised salt constitutes approximately only 30 per cent, of the domestic salt consumption of New Zealand.

7. To ensure a more general use of iodised salt it is recommended that the regulations be amended to provide that:

(a) Ordinary domestic salt shall be iodised.

(b) Non-iodised salt shall be sold only in packages labelled “Non-iodised” and with the addition “ The use of this salt exposes the user to the risk of developing goitre”.

8. The results obtained hitherto with the use of iodised salt are briefly reviewed and attention drawn to some apparent failures even when iodised salt has been used for all domestic purposes. These failures are attributed to the standard for iodised salt being too low.

9. It is concluded that for New Zealand a supplementation of at least 100γ per day is necessary to afford complete protection against goitre.

10. To provide the necessary amount of supplementation the iodine content of iodised salt in New Zealand requires to be raised. We recommend therefore that either

(a) If the domestic salt only is to be iodised the standard be fixed at from 5 to 6 parts of potassium iodide (KI) per 250,000 of salt, or

(b) If iodised salt is to be used in the manufacture of bread, butter, bacon and other salted foods, the standard be fixed at from 3 to 4 parts of potassium iodide (KI) per 250,000 of salt.

11. In New Zealand cabbage has not shown any marked goitrogenic activity as tested on rabbits.

12. Turnip roots showed sporadically a goitrogenic activity comparable with that found for the most active samples of cabbage in other countries.

13. In tests of Brassica seeds on rats, goitrogenic activity was found in rape seed, cabbage seed, steamed white mustard seed, and steamed black mustard seed.

14. The activity of rape seed was destroyed by steaming.

We have pleasure in acknowledging the financial help which we have received from the Sir John Roberts Endowment for Medical Research, from the Sir H. L. Ferguson Fund and from the Honorary Staff of the Dunedin Hospital, and for the co-operation of a large number of our colleagues in New Zealand and Samoa in the collection of specimens.

In the autumn of 1934 I received from Dr A. R. D. Adams, Superintendent of the Bacteriological Laboratory at Mauritius, 163 cultures of organisms. These had been isolated by him from the faeces of the inmates of the Beau Bassin Prison and Reformatory in a research on the intestinal flora and fauna of the general population in that island. In the course of the bacteriological examination the specimens of faeces had been cultured on plates of Endo's medium and incubated for 24 hours, at the end of which time non-lactose-fermenting organisms were picked off. A number of these strains were identified by Dr Adams as belonging to the typhoid, paratyphoid, or dysentery groups. One hundred and sixty-three strains which did not fall into these groups were sent to me for investigation.

At present the coli titre of water is almost universally determined by fermentation tests in sugar-containing media; the fermentation method of Eijkman (glucose-peptone solution at 46°2) and that of Bulir (neutral-red mannite bouillon at 46°) are current in many European countries, while in America fermentation in lactose bouillon at 37° is the standard test. Fermentation tests at 37° in lactose-containing media with the addition of bile and bactericidal dyes are also widely used (Great Britain, America).

1. A peptone salt agar appears to be the medium of choice in the preparation of suspensions of V strains of B. typhosus for Vi agglutination. The presence of heart extract may have a definite inhibitory effect on Viagglutination but the effect is irregular.

2. A safe method for the preparation of anti-Vi serum with virulent cultures is described.

3. Repeated endeavours to produce an anti-Vi serum by the use of formolized vaccines were unsuccessful.

4. A suspension of a V strain killed at 55° C. can be used as a vaccine for producing Vi agglutination.

5. The thermostability of the Vi antigen is discussed.

6. An analysis is made of the presence of Vi antigen in a number of freshly isolated and stock strains of B. typhosus.

7. A series of typhoid cases has been examined for Vi agglutination, and it is concluded that the latter is unlikely to be of any clinical value either in diagnosis or prognosis.

Acknowledgements. The writer wishes to express his thanks to his colleagues, Dr R. M. Humphreys, Senior Physician, Khartoum and Dr J. S. Hovell, Omdurman, for their valuable co-operation; and to Dr Ali Bedri, Khartoum Hospital, he is much indebted for assistance in analysing the clinical data and records of the typhoid cases.

The virus of Aujeszky's disease (pseudo-rabies) has been found to have a particle size of 100—150 mμ. Two strains were employed in these experiments, one that of Aujeszky, and the other Shope's “mad-itch” strain. The results with both strains were identical.

In our previous paper in this Journal it was shown that the temperature of 46°C.1 recommended by Eijkman and Bulir in their fermentation test is excessively high, as in water cultures it has a destructive effect on Bact. coli. This was in accordance with the previous work of Brown and Skinner (1930) and Skinner and Brown (1934). At the same time we were able to show that in cultures in Bulir's medium at 43° not only is the destructive effect of the excessively high temperature on Bact. coli removed but the reproduction and fermentation activity of this organism is distinctly stimulated. At 43° Eijkman's and Bulir's tests effectively distinguish between true Bact. coli communis and other strains.

A survey has been made of the different theories put forth to explain the nature of ultra-microscopic viruses, and it has been concluded as probable that they are representatives of some precellular forms of life. The writer's views have been given, and the probabilities have been expounded regarding the constitution of these forms, their evolution towards a composite cell, the conditions under which they exist, the means by which they obtain the necessary energy for their vital processes, and their food requirements. It has been suggested that at times some unit of a cell may undergo a partial or complete reversion to the independent precellular form. The possibility of the existence of other primitive forms of life, belonging to another biological world, has also been considered. The theories discussed have been analysed in relation to the known facts concerning virus diseases, transmissible bacteriolysis and cancers.

The reorganisation of the laboratories and the fitting up of various electrical and timing equipment, which were necessary to test the theories experimentally, have been explained, and a description has been given of some of the special pieces of apparatus made in the workshop for the experiments.

Experiments were carried out on an extensive scale with animal and vegetable materials containing known viruses, with muds, etc., presumed to contain precellular forms of life, and with bacteriolytic agents. Certain delicate bacteria, isolated from porcelain filtrates, were used as controls.

Attention was first given to indicators for growth, and it was found that minute quantities of selenium oxychloride incorporated in media resulted in many bacteria growing with a bright red colour.

From an extensive series of experiments on nutritive requirements, it was determined that beef extracts usually act detrimentally on bacteria, and they should not be used. The detrimental effect was marked with the bacteriolytic agents. Good agar media were gradually evolved. Rain water proved to be better than water from a town supply. A watery extract from certain clays supplied sufficient nourishment for many bacteria, but the media were improved by the addition of watery extracts of bracken ash and of the fronds of certain ferns, notably those belonging to the Asplenium group.

The associated conditions used during cultivation were varied in many ways, particular attention being given to the influence of solar rays and the energy emitted from projector lamps. In different experiments the wave energy was modified by reflection or filtration, different bands being tested both consecutively and intermittently. The materials used consisted of lenses, prisms, natural rocks and crystals, as well as animal, vegetable and chemical filters.

Many bacteria were found to tolerate solar rays when cultivations were made on suitable media, particularly if the action was intermittent. They were least tolerant to the region of the spectrum around 4000 Å.

A spore-bearing bacillus has been obtained from cultures of a mud nitrate on a leaf mould extract medium, placed under the intermittent influence of filtered solar rays. A group of the colonies developed a homogeneous waxy change, which was proved to be associated with a dissolution of the spores. It is suggested that the change is due to the presence of a “sporolytic agent”, although it has not been found possible to demonstrate the agent in a porcelain filtrate.

In a number of cases pleomorphic bacilli have been cultivated from old porcelain filtrates obtained from various diseased plants and muds. Many were found to be very sensitive as to their nutritive requirements. Most of them grew well in subdued daylight and under the influence of a 100-watt projector lamp.

Other porcelain filtrates produced granules on the surface of certain experimental media. When subcultures were made, granules associated with a marked milky opalescence of the medium occurred along the line of inoculation. No bacterium could be found in films made from the granules. The phenomenon appeared only on tubes of media which were autoclaved, set and inoculated on the same day. The milky opalescence can be produced without the presence of an unheated filtrate. The significance of the granules is being investigated.

Many comparative experiments have been carried out with suspensions of dead micrococci, either uninoculated or inoculated with living micrococci or a bacteriolytic agent or with both. It has been shown that suspensions of dead bacteria undergo more marked clearing when placed under the influence of solar or other rays than when placed in darkness. The effect is increased when the suspensions are prepared from cultures grown on tubes of media which have been autoclaved, set and inoculated on the same day, and it is particularly marked when the suspensions have been inoculated with living micrococci. The significance of these and other results has been considered, and attention has been called to the utilisation of the factors concerned for the purpose of freeing intracellular toxins in the preparation of various vaccines.

In conclusion I should like to record my appreciation of the valuable services rendered by my only assistant, Mr H. Frankham, the laboratory attendant and caretaker of the Institution.

The death certificates for cancer of the lung and of the larynx in males from England and Wales for the years 1921–32 inclusive, numbering 18,280, have been investigated.

Sources of error in statistical work on death certificates are discussed.

Latterly autopsies have been made upon about 28 per cent, of cases of cancer of the lung, and 9 per cent, of cases of cancer of the larynx. The increase in the recorded cases of lung cancer is not nearly accounted for by the increase of data obtained by autopsy.

The agricultural and coal-mining industries show a low incidence of cancer of the lung and of the larynx.

The factors which lead to silicosis appear not to be very active in producing cancer of the lung or larynx, but in metal grinders the incidence of cancer of the lung is 2¼ times that in the general population. A group of open-air occupations, where there is exposure to the dust of roads, have rather high ratios for cancer of the lung and of the larynx with the exception that motor drivers have a normal liability to cancer of the larynx. On the whole, no occupation involving exposure to any kind of dust has been found in which there is any very high incidence of cancer of the lung or larynx. Cases of cancer of the lung in asbestos workers are described in recent literature, but none has been found among the certificates considered here (up to 1932).

Workers exposed to coal gas and tar, and those engaged in the preparation and sale of tobacco, tend to show an increased prevalence of cancer of the lung.

Occupations concerned with the supply of alcohol have a high incidence of cancer of the larynx.

To investigate the occupational incidence of cancer thoroughly one should have before one, simultaneously, comparable figures for cancer of all parts of the body which could be effected by an external agent.

With regard to the view, that the recent rapid increase in recorded deaths from cancer of the lung is due to the detection of more cases by improved diagnosis, the very moderate ratio (129) for cancer of the lung in medical men is noteworthy, for this is an occupation where the availability of the existing methods for the detection of cancer is presumably at a maximum.

Data are given of the prevalence of cancer of the lung and larynx in men and in women, and of the rate of increase in the two sexes in recent years. The greater incidence of cancer of the lung upon men than upon women is discussed. The recent rate of increase of cancer of the lung in men is found to be not much greater than that in women, when these increases are reckoned in percentages.

The increase in recorded cases of cancer of the lung may be due to (1) an actual increase; (2) improvement in diagnosis; (3) fashion in diagnosis; or to any combination of these factors. A comparison is made between the increase of cancer of the lung, and of cancer of the prostate; the number of deaths attributed to cancer of the prostate appears to have reached a steady level.

No special occupations have been found to which the increase in the total of cases of cancer of the lung can be attributed; rural workers show an increase which is not much less than that in the general population.

No evidence has been found that tarring of roads has affected the incidence of cancer of the lung upon the general population. Such data as are available suggest that coal tar in the atmosphere, whether derived from roads, domestic chimneys, or any other source, does not readily give rise to cancer of the lung. Cotton-mule spinners show an especially small liability to cancer of the lung although they inhale air sprayed with an oil which produces cancer of the skin.

Improvements in diagnosis must have led to the detection of a larger proportion of the existing cases of cancer of the lung; whether there has been an actual increase in these cases cannot be decided from the data presented here, but a source of evidence on this question is suggested.

We are indebted to the Registrar-General for the data considered in this paper, and also for kindly permitting us to use some figures which have not yet been officially made public. We have received much assistance in the classification of occupations from some members of the Staff of the General Register Office, to whom we wish to express our gratitude. We wish to thank also Dr J. C. Bridge, Senior Medical Inspector of Factories, for information upon various matters, and especially upon silicosis. We are greatly indebted to Miss L. D. Henderson for much assistance in carrying out the calculations.

That the number of male births always exceeds that of females is well known to students of vital statistics, but the biological law responsible for the phenomenon has not yet been adequately determined though various theories have been offered in explanation. It has been suggested that it resulted from a high male conception rate which, although modified by an excess mortality of male embryos, nevertheless produced a masculinity of matured births. In more recent times the conclusions drawn by MacDowell & Lord (1925, 1925 a) from their experimental studies with mice have failed to support this view. They claimed that there was no correlation between the pre-natal mortality and the masculinity of live births, that the primary ratio at conception was almost identical with that at birth. These contentions were criticized by Parkes (1923, 1926), who, whilst maintaining the doctrine that the ante-natal mortality of mice “falls preponderatingly upon the males”, stated “that it is quite obvious that a great deal more information is required before any coherent story of the factors governing the sex ratio at birth in the mouse (and all other mammals) can be put together”.

The object of the inquiry reported upon in this paper was to determine whether there was any measurable association between the development of intelligence and the incidence of disease in school children.

In an article on Pneumonoconiosis published in 1935 I attempted to simplify the problem of lung diseases caused by exposure to dust in industry by means of a classification which might allow of the placing of individual cases into appropriate categories. The importance of some such classification has been emphasized during the past year or so by the gradual realization of the fact that, especially in the South Wales coalfield, cases of more or less disabling lung conditions are frequently met with which cannot conscientiously be fitted into the category of “silicosis”, as defined at the International Conference at Johannesburg in 1930. These cases cannot be “certified” for compensation under existing Statutes, and yet present a picture of respiratory distress and dyspnoea on exertion which marks them out as quite unfit for work.