The analysis of the serological results of blood specimens submitted during the course of the past 2 years for the Widal reaction has been made.

The sera from cases of typhoid and paratyphoid fever were examined in particular for their agglutinin content for the “H” and “O” antigens of B. typhosus and B. paratyphosus B. The results obtained indicate that it is essential to use the “O” antigen of B. typhosus, but no particular advantage has been derived, from the point of view of early diagnosis, from the use of B. paratyphosus B “O” antigen.

A comparison of the value of suitable living and killed antigens has been made. Either type of antigen appears to be equally effective, but for convenience and stability the suspensions issued by the Standards Laboratory, Oxford, have proved entirely satisfactory.

Cases showing the serological difficulties which arise when a mixed specific and non-specific form of B. paratyphosus B “H” antigen is used are described.

The author is indebted to the Medical Eesearch Council for a personal grant, and to Miss N. A. Davidson for much technical assistance.

1. Rats taken from mixed stock diet and fed synthetic diet containing an excess of magnesium carbonate developed urinary calculi in a large number of cases.

2. The incidence of calculi was much higher in the females.

3. Addition of excess of calcium carbonate to the diet prevented the formation of calculi.

4. Rats previously fed for a short time on the synthetic diet and normal salt mixture did not develop calculi, but suffered from severe catharsis.

5. Rats on mixed stock diet had a more acid caecum and colon than those on synthetic diet.

6. No significant alterations were found in the Ca, Mg or inorganic P of the blood on any of the diets.

7. Extra magnesium, or calcium, or sodium carbonate lowered the urinary phosphate excretion.

8. Extra magnesium or calcium had little effect upon the urinary excretion of the other, but tended in each case to lower the output.

9. Changes in the sex organs brought about by excessive intake of magnesium are described.

The writer wishes to thank Miss V. E. Leader for her watchful care of the rats.

1. In the list showing all substances yet tested in the order of their spermicidal powers, the first four substances are all quinones.

2. In the dihydroxybenzenes and their derivatives, the para-position of the two hydroxyl groups confers high spermicidal powers.

3. In the trihydroxybenzenes and their derivatives, the para-position of two of the three hydroxyl groups confers high spermicidal powers.

4. The introduction of a methyl group into quinones and into the di- and trihydroxybenzenes in certain positions increases the spermicidal power.

5. In the hydroxybenzaldehydes and their derivatives, the ortho-position of the hydroxyl and aldehyde groups confers high spermicidal powers.

6. Among the substances so far tested which may be found to be of practical use are orbhovanillin and methoxytoluquinone. These are highly spermicidal, sufficiently soluble and stable in solution. It remains to be seen whether they are harmless to the vagina.

1. Highly milled parboiled rice was found to be rich in the antineuritic vitamin B1, while roughly milled raw rice was deficient. In estimating the content of vitamin B1 the method of Chick and Roscoe was used.

2. Exact comparison was made of the vitamin B1 potency of two samples of rice, the one raw, the other parboiled, after similar degrees of milling. The vitamin value of the unmilled samples was equal, but when each was highly milled to an equal degree, as judged by weight of polishings removed in a hand rice mill, the parboiled sample retained the vitamin while the raw sample did not.

3. Polishings from parboiled rice were found to contain less vitamin B1 than those from raw rice.

4. Parboiled rice contains more P2O5 than raw rice milled to the same degree.

5. It is probable that when rice is steamed in the process of parboiling, the vitamin B1 and some of the phosphate contained in the germ and pericarp diffuse through the endosperm.

6. The P2O5 content of raw rice is a good index of vitamin B1 value, but in parboiled rice a low percentage of phosphate is compatible with the presence of the vitamin.

Thanks are due to Miss L. M. B. Patterson who kindly made the phosphate estimations recorded in the paper. I am indebted to the Director of Agriculture, British Guiana, for a number of rice samples. The rice mill used was kindly lent by Jackson and Son, 30, Mincing Lane, E.C. 3. I am grateful to Miss Chick for her continued interest in these experiments.

In a semi-closed institution, Greenwich Hospital School:

1. There was no constant relation between the prevalence of cases and carriers of virulent, or avirulent, diphtheria bacilli.

2. Carrier rates showed a seasonal periodicity with a maximum in the autumn and a minimum in the winter school term.

3. High rates for carriers of virulent bacilli were found in the absence of clinical diphtheria and presence of numerous Schick susceptibles.

4. As much as 40 per cent. of a random sample of healthy boys, none of whom contracted diphtheria, were discovered to harbour diphtheria bacilli (M.D.)1 within 1 year, during which the average carrier rate in the sample was 6·8 per cent.

5. The carrier rate for avirulent diphtheria bacilli, among boys recently infected with virulent, was three times the expected rate.

6. The carrier rate for virulent diphtheria bacilli, among boys recently infected with avirulent, was no higher than the expected rate.

7. The frequency of avirulent diphtheria bacilli infections was twice as great among Schick susceptibles as among Schick immunes.

8. Carriers of virulent bacilli (with five exceptions) were always found to have Schick-negative reactions, in spite of their being more frequent among the junior members of the institution.

9. Carriers of avirulent diphtheria bacilli were as common among the senior as the junior Schick-immune members of the school.

10. Carriers of avirulent bacilli were less frequently found in those Schick-susceptible members of the community who were most quickly immunised by artificial diphtheria antigens.

11. The hypothesis that, when a Schick susceptible is infected with virulent diphtheria bacilli, the latter often acquire avirulence, could satisfactorily explain many anomalies in the distribution of latent infection with diphtheria bacilli and Schick immunity.

[Since this article went to press I have received a reprint from A. Garrido-Morales and 0. Costa (“ The Mechanism of Natural Immunity to Diphtheria,” Amer. J. Hyg. (1931), 14, 89), who describe the distribution of diphtheria carrier infection and Schick immunity in a school at San Juan, Porto Rico. In the main their results parallel those obtained at G.H.S. The most important difference between the tropical and G.H.S. observations was found in a sample of children, who were Schick tested and swabbed synchronously, in which the frequency of virulent carrier infections was greater among Schick susceptibles than Schick immunes. (However, only 9 T.C.D. infections were found among 642 children, but 5 of these were discovered among the 194 Schick susceptibles in this group.)—S. F. D.]

White rats reared from the age of 30 days to 275 days under vita glass, and properly fed, do not grow at a different rate from those reared under ordinary glass.

The offspring of these rats, kept in the same environment, grow at the normal rate when compared with controls born and reared under ordinary window glass.

A short discussion of these results is given in the text.

Addendum. The temptation to use an artificial source of ultra-violet rays having proved irresistible, a further experiment was performed with 20 males, 10 under vita glass and 10 under window glass. These were exposed to the radiation of a Hanovia quartz mercury vapour lamp on alternate days, at a distance of four feet from the burner. The growth curves are shown on Chart V, and the lengths of exposure have been entered on this chart: it will be seen that the results are the same as with natural sunlight.

Difficulties in cultivation outside the body have rendered the exact study of the immunity reactions of the filtrable viruses less easy than in the case of many of the bacteria, and the extension of our knowledge of immunity in these infections is at the present time largely dependent upon observation of the behaviour of human beings when exposed to infection through natural channels. For this reason it is important that the utmost use should be made of such reliable statistics as are available for the study of the epidemiology of such diseases as Encephalitis Lethargica and Acute Anterior Poliomyelitis, with a view to understanding their mode of spread and obtaining some clue as to how they may in the future be controlled.

The group of organisms included in the term B. mucosus capsulatus has continued to intrigue bacteriologists for more than thirty years, mainly on account of the problems of academic interest which arise when any attempt is made to define the characters of the group as a whole or to classify its members into types. Proof that such problems still exist is to be found in current text-books in which certain discrepancies occur regarding the biochemical reactions ascribed to the various members. There is also uncertainty as to the inclusion of B. lactis aerogenes in the group (Topley and Wilson, 1929; Wilson, 1929). Much of the difficulty arose from the fact that Friedländer's bacillus, one of the first members of the group to be isolated (1883), was studied from a morphological standpoint, while Escherich who described B. lactis aerogenes in 1886 stressed its biological similarity to B. coli. A chasm was thus created between B. lactis aerogenes and Friedländer's bacillus which has not been bridged to the present day, although these organisms must always have resembled, more than they differed from, each other; e.g. Bergey (1929) classifies B. lactis aerogenes with coliform types under Bacterieae and places Friedländer's bacillus in the tribe Klebsielleae Trevisan, i.e. encapsulated Gram negative organisms encountered principally in the respiratory tract, whose fermentation reactions are not given in full. Organisms morphologically similar to Friedländer's bacillus were found to be widely distributed, and in 1896 Fricke named the group B. mucosus capsulatus. There is still little criticism to be made of his general description to the effect that the members were Gram-negative, possessed capsules, showed marked pleomorphism and did not form spores; they grew on a variety of media in a profuse slimy layer, and in gelatin stabs they did not liquefy, but showed the so-called “nail” growth; in addition to this, most of the bacteria classed under this head formed a moderate amount of indole and fermented carbohydrates in solution with production of acid and gas. In an attempt to type members of this group Perkins (1904) admitted that the current knowledge of technique had been almost exhausted in the effort to separate one member from another, but on the basis of certain biochemical differences he was able to distinguish three classes, of which the first was the largest:

1. An epidemic of meningococcal meningitis, due to Type II meningococcus, occurring in a large native population is briefly described.

2. A method of preparing prophylactic meningococcal vaccine on a large scale, and its experimental application in the epidemic is demonstrated.

3. The results obtained in two similar groups of natives, one inoculated with meningococcal vaccine and the other with T.A.B. vaccine, as to the incidence of, and death rate from, meningococcal meningitis are detailed.

Methods for measuring the temperature and humidity of the air beneath the shirt are described.

Conditions of temperature and humidity under the shirt are described, for a resting person, with external temperatures varying between 0° C. and 41° C., under different atmospheric humidities. The air beneath the shirt varied between 23° C. and 37° C., and 23 and 70 per cent. relative humidity. The saturation deficiency of the air beneath the shirt varied very little—only between 13 and 18 mm.—in all the observations taken.

I am indebted to Dr P. A. Buxton for many helpful suggestions and for reading the manuscript. Also to Prof. G. H. F. Nuttall, F.R.S., for drawing my attention to literature on the earlier work.

1. Seven strains of Strept. mucosus are described which have the following characteristics: large “mucous” colonies on serum agar and other media referred to in the text, with a subsequent particular form of lysis; no growth occurred on gelatin at 22° C., although the organisms were still viable on this medium after 10 days at this temperature; inulin was fermented and milk acidified without any clot formation; the organisms were only partially soluble in bile.

2. All our strains were isolated from patients suffering from acute infections of the respiratory tract.

3. Inflammatory and suppurative lesions were produced in rabbits and guinea-pigs by inoculation of the live organisms.

4. Vaccines may prove highly toxic when injected subcutaneously even in small doses into patients suffering from these infections.

5. Immune sera containing precipitins were formed in rabbits inoculated with the live organisms, but not when filtered toxins or dead cultures were employed.

6. Precipitin antigens were obtained by high-speed centrifugalisation of serum-broth cultures until the supernatant fluid was glass clear, and from centrifugalised suspensions in saline from egg cultures, but after filtration of the cultures through a Seitz filter or Berkefeld V candle the filtrates were inert.

A strain of Proteus vulgaris, recovered from a case of cystitis, showed extreme pleomorphism in a primary culture on ordinary agar.

Pleomorphism was not found in sub-cultures on media free from added NaCl, but it appeared in the presence of a limited range of NaCl concentrations; with still higher concentrations it was not observed, although growth occurred. It was rarely found in cultures which grew with difficulty.

Pleomorphism, occurring under the conditions mentioned as to salt concentration, was most marked in young cultures which grew vigorously; it usually disappeared as the cultures aged; and it became less and less evident in serial sub-cultures on medium containing the same amount of salt.

The morphology of the organism differed on different media, e.g. filamentous on salt-free agar, short bacillary on MacConkey's agar, but it was practically constant in repeated sub-cultures on any one type of medium.

Pleomorphism could be re-induced on any of the media used by suitable alteration of its NaCl content (increase or decrease). Pleomorphism was not determined by variation of the H-ion concentration of salt-free media; nor by variation of the temperature of incubation of cultures; nor by growth in fluid media as opposed to solid media.

After nearly 4 years under laboratory conditions the organism is still sensitive to variation in the NaCl concentration of its environment, as evidenced by pleomorphism; but pleomorphism is now less extreme than it was originally.

Pleomorphism is still most marked in young sub-cultures on media with suitably altered salt concentration, but it is sometimes difficult now to induce pleomorphism unless a stock culture several weeks old is used as the inoculum.

The pleomorphism comprises aberrant forms similar to many of those which are regarded by certain observers as evidence of stages in a life cycle; but, in the case of the organism described, these forms can be induced by the simple expedient of altering the salt concentration of the medium on which it is grown. The occurrence of such forms is thus, of itself, no proof of a life cycle.

This investigation has been undertaken at the request of the Birmingham Committee of the British Empire Cancer Campaign. The chemical work has been carried out under the general advice of Prof. W. N. Haworth, F.R.S., in the Department of Chemistry, and the work on the clinical side under Prof. G. Has well Wilson, M.D., in the Department of Pathology.