bluuebunny/crossref_metadata_2025 huggingface dataset:
Routine Methods of Shellfish Examination with References to Sewage Pollution
Authors: Johnstone James
Published: May 2009

(1) At present no public authority possesses legal power to deal with the question of the contamination of shellfish.

(2) It is not sufficient to test shellfish exposed for sale in a market or shop. These may have been contaminated subsequent to removal from the fishery; and multiplication of the contained bacteria may have taken place. The results of such analyses may lead to unjustifiable condemnation of a laying. It is essential that a topographical examination should be made and that samples for analysis should be taken from the laying itself.

(3) In the case of natural shellfish beds there is so much variability in the conditions with regard to the susceptiblity to pollution that a fairly large number of the animals must be examined. The labour of the analyses is therefore so great that the development of some simple routine test for faecal contamination is most desirable. Since most desirable. Since most natural shellfish layings are situated within the “sewage zone”, and therefore contain B. coli, quantitative results are essential.

(4) There are considerable differences in practial routine work in regard to the methods of isolation of intestinal organisms from shellfish; and aslo with respect to the number and nature of the reactions necessary for the identification of B. coli. It is desirable that some generally recognised series of tests should be uniformly adopted by bacteriologists engaged in such work. Further, different micro-organisms, possibly of varying degrees of significance as indicators of faecal contamination, may have been confused. There is possibly some variation in cultural characters in B. coli, and investigation of this variability is desirable. Investigation of the changes in cultural reactions undergone by intestinal organisms when entering the sea, or the tissues of marine shellfish, is also very desirable.

(5) Remedial measures other than the simple closure of a contaminated laying might be suggested. It is possible to subject the shellfish to treatment which will cause them to clean themselves of contained sewage bacteria. The source of the pollution may be removed; and sterilisation of the shellfish may be practised.
The Precipitin, Complementbinding, and Anti-opsonic Tests in Tuberculous and Normal Cattle
Authors: Porter A. E.
Published: May 2009

The recognition of latent tuberculosis, difficult as it often is in the human subject, is of necessity more difficult in the case of cattle. It is especially in early disease that the serum reactions prove often most useful as an aid to diagnosis, but in cattle a proof is also often desired that no pronounced disease is present, because it is by no means of rare occurrence that an apparently fat and healthy animal must be rejected after slaughter.
On the Alterations in Haemolytic Immune-body which occur during the Process of Immunisation
Authors: Browning Carl H. , Wilson G. Haswell
Published: May 2009

(1) When rabbits are injected intraperitoneally with ox's red blood corpuscles the haemolytic immune-body which is developed shows qualitative differences at different stages of immunisation.

(2) The immune-body molecules which appear in the serum in the early stage of immunisation (e.g. four to eight days after a single injection of 2 to 4 c.c. of red blood corpuscles) are deficient in the power of causing absorption of complement when added to the corresponding blood corpuscles. This is most clearly brought out by the very slight increase in complement absorbed under the influence of multiple doses of immune-body as compared with the amount absorbed by one dose. The deficient complement absorption does not depend to any marked degree on deficient combination of immune-body with the receptors of the red corpuscles.

(3) When, after repeated injections of blood corpuscles, immunisation has been carried to such a stage that an immune-body is produced which is very active in causing absorption of complement, then it is found that on ceasing to give further injections the relative complement-combining power remains high after the immune-body content of the serum as measured by the haemolytic dose has fallen to a very considerable extent.

So far as we are aware the occurrence of such alterations in the properties of immune-body during the process of immunisation has not hitherto been noted.
On the Varieties ofBacillus Coliassociated with the House-fly (Musca Domestica)
Authors: Nicoll William
Published: May 2009

1. A study of the natural bacterial flora of the house-fly appears to be essential in forming a correct estimate of the part played by flies in transmitting pathogenic bacteria.

2. The house-fly may carry at least 27 varieties ofBacillus coli, by far the most frequent of which areB. coli communisand MacConkey's bacillus No. 71.

3. As far as can be judged from the character of these colon bacilli the house-fly derives its bacterial flora equally from excremental matter and from other sources.

4. Certain non-lactose fermenting bacilli appear to be capable of multiplying in the intestine of the house-fly. Of these Morgan's bacillus No. 1 is a not infrequent inhabitant of the fly's intestine andB. paratyphosus βhas been found on two occasions.
On the Mechanisms by which protection against Infectious Disease is acquired in “Natural” Epidemics
Authors: Greenwood M. , Newbold E.M. , Topley W. W. C. , Wilson J.
Published: May 2009

The problem which we shall discuss in this communication is of great importance, is perhaps the most important of all epidemiological problems, and we are far indeed from supposing that we have solved it. We think, however, that the work we have done is certainly useful in enabling us, and others, to state the problem correctly, and possibly useful in suggesting a first approximation to its solution.
Further Studies in Anti-Rabies Immunisation. Rabies Virus—Exalted and Classical Strains Compared
Authors: Stuart G. , Krikorian K. S.
Published: May 2009

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.
Pleomorphism ofProteus VulgarisDetermined by Sodium Chloride Content of Culture Medium, and Simulating Stages in a Life Cycle
Authors: Dunlop E. M. , Maitland H. E.
Published: May 2009

A strain ofProteus vulgaris, recovered from a case of cystitis, showed extreme pleomorphism in a primary culture onordinary 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.
The Comparative Bactericidal Action of Normal Serum, “Whole” Blood and Serum-Leucocyte Mixtures; with Further Observations on the Bactericidal Mechanism of Normal Serum
Authors: Mackie T. J. , Finkelstein M. H. , Van Rooyen C. E.
Published: May 2009

1. Normal “whole” blood and serum-leucocyte mixtures may exert a bactericidal effect when the serum (or plasma) is inactive in this respect, and may possess quantitatively greater bactericidal properties than serum (or plasma), when the latter is activeper se, but such effects are relatively weak.

2. Leucocyte suspensions may exhibit an initial bactericidal action on certain bacteria, but this is usually weak and is followed by a pronounced growth-promoting influence on the surviving organisms.

3. Under certain conditions normal “whole” blood and serum-leucocyte mixtures are inferior to serum (or plasma) in bactericidal power. This is observed when the serum (or plasma) is strongly activeper seand is due not merely to an inhibition of the bactericidal action of the leucocytes, but also to a lessened effect of the serum-bactericidins.

4. The comparative bactericidal power of normal “whole” blood or serumleucocyte mixtures on the one hand and serum or plasma on the other depends on the activity of the serum; when this is relatively weak, blood shows an enhanced action; when strong, blood is less active.

5. The above findings apply to a wide variety of bacteria irrespectively of biological species.

6. Bacterial extracts possess marked inhibitory properties on the bactericidal action of serum (or plasma), but not to any extent on the bactericidal properties of the leucocytes as evidenced by the approximately equal influence of such extracts on whole blood and serum respectively.

7. Dead bacteria in certain numbers produce inhibition of the bactericidal action of serum (or plasma), but exert a greater inhibitory influence on the reaction of “whole” blood.

8. It is suggested tentatively that when the serum is strongly bactericidal the killed organisms on being phagocyted along with living bacteria interfere with the intracellular destruction of the latter which at the same time are protected from the serum-bactericidins.

9. The paper also includes certain data regarding the time of maximum bactericidal action by serum towards various organisms and the occurrence of growth-promoting action following an initial bactericidal effect.
The Spermicidal Powers of Chemical Contraceptives. V. A Comparison of Human Sperms with those of the Guinea-Pig
Authors: Baker John R.
Published: May 2009

1. Human and guinea-pig sperms are susceptible to the most diverse chemicals to almost the same degree.

2. There exists a substance in human semen which protects both human and guinea-pig sperms against certain chemicals, especially sodium oleate, orthovanillin and potassium borotartrate.

3. When perfectly fresh human semen is not available, the spermicidal powers of substances may be tested by using guinea-pig sperms suspended in human semen which has been kept cool.
The Dissimilarity of the Results of Precipitin Titrations Performed with a Constant Amount of Antiserum and with a Constant Amount of Antigen
Authors: Taylor G. L.
Published: May 2009

1. Antisera, made against crystalline egg-albumin, have been examined by titrating a constant amount of antiserum against falling amounts of the antigen (the usual Dean and Webb method), and also by the reverse procedure in which the amount of antigen was constant and that of antiserum varied. The ratios by the two methods were never found to agree; nevertheless, in the majority of cases the relationship which the ratio by one method bore to the ratio by the other method was of the same order, and it is possible that this relationship is constant for crystalline egg-albumin and its antisera.

2. The conclusions reached in my previous work (1931) require modification, because in those experiments insufficiently extensive ranges were used and as a result it was found that when varying amounts of anti-horse serum were titrated against a fixed amount of antigen, particulation was quickest in the tube containing most antiserum.

3. Titrations by the reverse method over a fairly considerable range have provided evidence that the proportions of crystalline egg-albumin and a given homologous antiserum favourable for the most rapid particulation are constant despite absolute quantitative changes. The proportions in which these reagents particulate most rapidly are similarly constant in titrations by the usual Dean and Webb method.

4. Why the two methods of titration give different results I am unable to explain, but the point of optimal particulation found by the Dean and Webb method probably coincides with the point of neutrality of antigen and antibody. Since in the Ramon (1923) method of titrating diphtheria toxin and antitoxin the reverse method, with constant antigen and varying antiserum, is used, the work reported here suggests that the determination of the relationship to each other and to animal values of the results of titrations of toxin and antitoxin by both methods might yield helpful information.

5. Some points of practical importance in the performance of optimal proportions titrations are appended.
Sporadic Infections in Aberdeen due to Food-Poisoning Organisms of the Salmonella Group
Authors: Smith J.
Published: May 2009

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 Application of Photo-Electricity to the Determination of Bacterial Growth Rate
Authors: Pulvertaft R. J. V. , Lemon C. G.
Published: May 2009

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.
Control of Scarlet Fever by Active Immunisation
Authors: Faulds J. Steven
Published: May 2009

This paper deals with the result obtained after testing, by the “Dick” method, the susceptibility of a series of adults to scarlet fever toxin. The toxin used was produced by the Wellcome Physiological Research Laboratory. While various strengths of solutions were tried to begin with from 1:2500 to 1:250, no advantage was found to result from the use of a solution stronger or weaker than 1:1000. The tests were, therefore, carried out with the standard “Dick” toxin as supplied by this firm.
Agglutinins for the Typhoid-Paratyphoid Group in a Random Sample of the Population of British Guiana
Authors: Giglioli George
Published: May 2009

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 Measurement of the Opacity of Bacterial Cultures with a Photo-Electric Cell
Authors: Alper Tikvah , Sterne Max
Published: May 2009

1. A photo-electric cell was used to measure photometrically the opacity of cultures ofSalmonella gallinarumgrowing 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.
The Type of Coliform Bacilli Prevalent in Urine and their Significance, with Special Reference to the Sanitary Aspects
Authors: Burke-Gaffney H. J. O'D.
Published: May 2009

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 theaerogenestype,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 thecoligroup are quickly outnumbered by theaerogenesgroup once they leave the faeces, and also that the presence of theaerogenestype is not confined even in large numbers to an extra-corporeal habitat.

4. In water bacteriology the constancy or change in the relative proportions ofcoliandaerogenesstrains present is the goal at which to aim. Theaerogenesvariety 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) theaerogenesstrains 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 identifyingB. coliof 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.
An Analysis of 510 Strains ofCorynebacterium Diphtheriae
Authors: Carter H. S.
Published: May 2009

Since Anderson, Happold, McLeod and Thomson (1931) described their division of the varieties ofCorynebacterium diphtheriaeinto three groups—gravis, intermediate andmitis—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.
“Nose-Opening” Rays
Authors: Hill Leonard
Published: May 2009

Dufton And Bedford (1933) have denied the claim made by me (1932) that bright sources antagonise the “nose-closing” rays given off by dull red and dark sources of heat. They are supported by Winslow, Greenburg and Herring-ton (1934). These five authors have used the same method, viz. the insertion of a well-fitting tube in one nostril of the subject, the connection of this tube with a recording instrument, and the leaving open the other nostril for breathing, the mouth being kept shut.
Observations on the Toxic Fractions of Scarlatinal Streptococci
Authors: Green C. A.
Published: May 2009

1. Among a series of strains of haemolytic streptococci from thirty-five cases of scarlatina in the first week of illness, fourteen were found to correspond with one or other of Griffith's serological types I, II, III and IV.

2. Of these fourteen strains, twelve were selected for further examination and found to yield a true heat-labile exotoxin completely inactivated by heating for 30 min. at 100° C.

3. The concentration of exotoxin in 0·5 per cent, glucose broth cultures was at a maximum after 96 hours' incubation, and thereafter on further incubation progressively diminished.

4. No qualitative difference could be detected among the exotoxins from the different strains, the test criterion being the dermal reaction in Dick-positive persons.

5. Cultures of organisms of the same or different serological type isolated from the same source and thereafter similarly treated yielded approximately equivalent amounts of exotoxin.

6. Broth culture filtrates also contained an acid-insoluble toxic fraction, the concentration of which increased with the age of culture and which appeared to be identical with a similar acid-insoluble fraction derived from an alkaline extract of washed bacterial bodies.

7. This acid-insoluble fraction was extremely heat-resistant, 3 hours' boiling at 100° C. being required for inactivation. In this respect the acid-insoluble fraction corresponded to the bacterial endotoxins.

8. The acid-insoluble fractions from cultures of the same serological type produced equivalent skin reactions in susceptible persons.

9. The acid-insoluble fractions from cultures of different serological types differed qualitatively as determined by skin reactions.

10. The reaction to crude filtrate was found to be the sum of the reactions to the exotoxin fraction and to the acid-insoluble fraction present in the filtrate.
A New Method for Measuring Carcinogenicity
Authors: Twort C. C. , Lyth R.
Published: May 2009

Mineral oils recovered from the peritoneal cavity of injected mice showed in all sixty-one instances, with the exception of liquid paraffin, a fall in the refractive index. This phenomenon is presumably due either to a chemical change (? oxidation or reduction) in the constituents of the oils brought about by the juices of the animal organism, or to a mechanical change resulting from the removal of selected constituents to other parts of the animal. This test will possibly prove to be superior to that of skin applications and estimation of the refractivity constants for measuring the amount of carcinogenic constituents in mineral lubricating oils and it has the advantage of necessitating the use of only one animal instead of 100. We are of opinion that our experiments may be of far-reaching importance. They carry us a definite step nearer to the understanding of the mechanism of cancer formation.
The size and the duration of air-carriage of respiratory droplets and droplet-nuclei
Authors: Duguid J. P.
Published: May 2009

1. The sizes of the droplets and droplet-nuclei produced by sneezing, by coughing and by speaking, were studied by the microscopic measurement of 12,000 droplet stain-marks found on slides exposed directly to mouth-spray, and of 21,000 stain-containing droplet-nuclei recovered from the air on to oiled slides exposed in the slit sampler.

2. From these measurements it was calculated that the original diameters of the respiratory droplets ranged from 1 to 2000 μ, that 95 % were between 2 and 100 μ and that the most common were between 4 and 8 μ. Similar size distributions were exhibited by the droplets produced in sneezing, in coughing and in speaking, except that, in the case of sneezing, the smaller droplets were relatively more numerous.

3. The respiratory droplet-nuclei were found to range in diameter from ¼ to 42 μ; 97 % had diameters between ½ and 12μ; the commonest diameter was between 1 and 2 μ.

4. The proportion of droplets of each size which will contain bacteria, whether commensal or pathogenic, is determined by the size of the droplets and by the numbers of bacteria in the secretions atomized. Calculations made on the basis of the size distributions obtained in this investigation indicated that few of the smaller droplets, and thus few of the droplet-nuclei, are likely to contain pathogenic organisms. Droplet-spray is unlikely to give rise directly to true airborne infection unless very large numbers of pathogenic organisms are present in the secretions of the anterior mouth.

5. The persistence of droplet-nuclei in the air of a 1700 cu.ft. room and of a 70 cu.ft. chamber was investigated by sampling the air with the slit sampler at intervals following sneezing.

6. When the air was not artificially disturbed by a fan, the time taken for the disappearance from the air of 90% of the bacteria-carrying droplet-nuclei varied from 30 to 60 min.; the nuclei larger than 8 μ in diameter usually disappeared within 20 min., and the nuclei larger than 4 μ within 90 min.; the smaller nuclei, few of which contained bacteria, remained airborne for much longer periods, on one occasion for at least 30 hr. When a fan was run throughout the experiment, the nuclei disappeared from the air much more rapidly.
Thermal comfort in warm, humid atmospheres Observations in a warship in the tropics
Authors: Ellis F. P. , Navy Royal
Published: May 2009

Naval ratings serving in a warship in the tropics answered a questionnaire concerning their sensations of warmth at meal times on the mess-decks during two investigations carried out at an interval of 6 months when the ship was proceeding between tropical and more northerly waters. Temperature measurements were recorded at the same times as the questionnaires were completed by the subjects.

It is proposed that the upper level of warmth to be accepted in the design of ventilation systems for accommodation spaces should be those conditions when either more than 80% of persons feel reasonably comfortable or less than 20% observe the presence of unevaporated sweat on their skin, which corresponds to effective temperatures of 79 and 78° F. respectively, according to the majority opinion in these two investigations. The latter figure of 78° F. is suggested as the upper level to be accepted for men living under these conditions.

The upper level of the optimum or ideal zone for comfort, when equal proportions of persons reported that they were either cool or warm, was observed to be at 74° F. effective temperature.

The proportions of men who were uncomfortably warm at different levels of warmth were related to the proportions who reported that their skin was wet with unevaporated sweat. Very few observed that they were sweating, whatever the air velocity or their clothing, when the dry-bulb temperature was below 83° F., and the wet-bulb temperature below 75° F.

Brisk circulation of the air on the mess-decks made an increasingly large contribution to the comfort of these very lightly clad men as the air temperature rose from 85 to 89° F., but as the temperature fell below 83° F. variations in air Thermal comfort in the tropics 431 movement had little effect on the proportions of persons who were reasonably comfortable under these warm conditions.

Thermal discomfort was reported by an increasing number of men within a temperature zone where others have shown by experiment that there will occur a statistically significant decrease in the skilled performance of men who are acclimatized to working at high temperatures.

This paper is published by the permission of the Admiralty and the Medical Research Council's Royal Naval Personnel Research Committee. The investigations described were made possible by the active interest of Captain H. S. Hopkins, C.B.E., Royal Navy, and Commander W. Elliot, D.S.C., Royal Navy, the excellent facilities which they placed at the disposal of the observers, and the wholehearted co-operation of the naval ratings who acted as subjects. I am indebted to Dr T Bedford for advice and criticism and to Mr Cheng Swee Guan and Sick Berth Attendant W. F. Montague, Royal Navy, for care in tabulating the data, preparing the illustrations and technical assistance.
Variation of Bacillus anthracis with special reference to the non-capsulated avirulent variant
Authors: Chu H. P.
Published: May 2009

Normal virulent B. anthracis all possess the genetical potentiality of producing capsules, but the capsule is only produced in vivo or under special cultural conditions suitable for capsule formation, especially in the presence of CO2.

During multiplication the potentially capsulated cells regularly produce a small number of a stable non-capsulated avirulent variant. All laboratory stock cultures of B. anthracis examined were found to contain from 0·14 to 32·4% of this avirulent variant. The variant has also been demonstrated in hair and wool from anthrax endemic areas, which suggests that the dissociation may also occur in nature.

Both the normal potentially capsulated cell and the variant incapable of producing capsules grow on plain agar in air as rough colonies with apparently non-capsulated cells. But when they are grown on serum agar in the presence of CO2, the normal potentially capsulated cell gives rise to a smooth mucoid colony with fully capsulated cells, while the variant still produces a rough colony with non-capsulated cells. If we regard the smooth mucoid colony produced by normal virulent B. anthracis on serum agar in CO2 as the normal colony form of B. anthracis, then the dissociation of the avirulent non-capsulated variant with the rough colony form falls in line with the usual S-R dissociation of other bacteria.

The more widely known variation of B. anthracis, which had long been held as an exception to the usual S-R variation of other bacteria, refers to colonies grown on plain agar in air. This variation is different from the one just described and is not so clear-cut and significant. Its underlying cause is not quite clear except that the chain length of the growth appears to play some part.

A summarized picture showing the whole range of variation in colony appearance and cell structure of B. anthracis is presented.
The Vi antigen of Salmonella paratyphi B
Authors: Felix A.
Published: May 2009

1. Salmonella paratyphi B possesses a Vi antigen essentially similar to the Vi antigens of Salm. typhi and Salm. paratyphi A.

2. The biological function of the Vi antigen of Salm. paratyphi B is to protect the O antigen against the action of the natural or immune O antibody, thereby increasing the virulence of the microorganism.

3. The most suitable paratyphoid-B vaccine strains are those that develop both the Vi and the O antigens in maximum quantities. The methods of testing vaccine strains of Salm. paratyphi B are essentially the same as those applied to the virulent Vi+O form of Salm. typhi.

4. Evidence is brought to show that Kauffmann's conclusion that Salm. paratyphi B does not develop Vi antigen is unfounded. The so-called O-factors V and V obviously cannot be classified as O antigens.

5. It is suggested that the symbol V of the Kauffmann-White schema be abandoned and this antigenic component be classed as the Vi antigen of Salm. paratyphi B.
Salmonellosis in Northern Ireland, with special reference to pigs and salmonella-contaminated pig meal
Authors: Newell K. W. , McClarin R. , Murdock C. R. , MacDonald W. N. , Hutchinson H. L.
Published: May 2009

1. Salmonella incidents in Northern Ireland from 1951–58 are compared with the published findings in England and Wales.

2. Caecal swabs from 489 pigs killed in two bacon factories showed a salmonella isolation rate of 2%.

3. Salmonella organisms were isolated from twenty-three out of 100 samples of caecal faeces and from only six of 100 caecal swabs taken from the same animals. Three per cent of meat samples from these pigs and 70% of sausage samples from this meat contained Salmonellae.

4. Rectal swabs from 162 pigs on five farms producing infected pigs showed Salmonellae in 9% of those examined.

5. Twenty-four per cent of pig-meal samples taken on these farms contained Salmonellae, and the same salmonella types were found in the meal at the mill and in fish meal and bone meal before mixing.

6. It is probable that some salmonella types pass from feedingstuffs through pigs to human food and cause human infections.

We should like to express our thanks to Dr Joan Taylor of the Salmonella Reference Laboratory, Colindale, for typing many of the Salmonellae; to Mr J. Stuart of the Veterinary Division, Ministry of Agriculture, Northern Ireland, for help in sampling at an abattoir and on the farms; to the staff of the Northern Ireland Hospitals Authority, Central Laboratory, for technical assistance; to Mr J. Patton and Dr D. Luke for much help and advice at many stages of this inquiry; to Miss A. McCann for the secretarial work; to the Northern Ireland Hospitals Authority for a grant towards the expenses in 1958; and to our colleagues in the Local Authorities, General Practice, on the farms and in the factories who were always most helpful and co-operative.
Effect of constant length of day on reproduction in albino mice
Authors: Mathewson Sue Flick , Davis David E. , Christian John J.
Published: May 2009

Studies on reproduction in a colony of albino mice before and after length of daylight was made constant show no change in litter size. However, there was an increase in the number of post-partum pregnancies after light was made constant and, during the first month thereafter, females were older at first parturition than in previous months.
The use of radiation to estimate the numbers of micro-organisms in air-borne particles
Authors: Lidwell O. M. , Noble W. C. , Dolphin G. W.
Published: May 2009

The form of the killing curve obtained by bombaring micro-organisms with high energy electrons enables an estimate to be made of the numbers of individual viable organisms present in the aggregates or clumps comprising the sample. Samples of Staph. aureus collected from the air of two hospital wards have been found to consist of aggregates containing, on the average, only about four viable cocci per air-borne particle. These samples were taken during quiet periods and during periods of active dispersion of the organism but there was no active spread of staphylococcal disease at any time.

The work on the linear accelerator was carried out with the aid of grants provided by the Treasurer and the Board of Governors from the Discretionary Fund of St Bartholomew's Hospital, to whom we wish to express our gratitude.
A protective cabinet for the post-mortem examination of infected animals
Authors: Couling C. W. , Rees R. J. W.
Published: May 2009

A special cabinet was designed to protect the operator, during post-mortem examinations on animals infected with pathogenic organisms, against the risk of enhaling infected material and the surrounding area from becoming contaminated. The cabinet was suitable for small animals including mice and guinea-pigs.
The growth ofLeptospira australisB in the kidneys of mice in the incipient experimental carrier state
Authors: Faine S.
Published: May 2009

The growth ofL. australisB in the kidneys of young mice which become carriers was followed after experimental intraperitoneal infection. There was a primary growth corresponding to generalized acute infection and terminated at the time of appearance of antibody. A secondary growth bf leptospirae followed in the kidneys alone about 7–10 days after infection, coinciding with the onset of leptospiruria and recovery from infection. Subsequently mice carried about 106–107leptospirae in their kidneys permanently.

The leptospirae in the urine or in the kidneys of carriers were resistant to the action of antibody in the serum or urine of the host animal, or in rabbit antisera prepared against mouse-renal leptospirae or against cultured leptospirae of the infecting strain. No antigenic differences were detected between renal and cultured leptospirae. An analogous situation is the growthin vitroof leptospirae in homologous antiserum. The mechanism permitting growth of leptospirae in homologous antiserumin vivoorin vitrois unknown.

The carrier condition results from the ability of virulent leptospirae to (i) grow in the host and produce lesions in the primary, acute generalized infection, (ii) grow in renal tubules in the presence of antibody.
Immunity to vaccinia induced by small doses of active virus
Authors: Amies C. R.
Published: May 2009

Minimal quantities of active vaccinia virus in the form of a purified elementary body suspension were injected subcutaneously into rabbits. The amount administered was about 10 minimal infective doses as measured by intracutaneous titration and tissue culture assay: this is equivalent to about 1·3± 10−5μg of virus protein. The immune response to this minimal quantity of virus was determined by complement-fixation and virus neutralization tests and also by skin sensitivity tests. The results indicated that viral proliferation occurred to an extent sufficient to sensitize the tissues to the virus protein. Measurable amounts of antibody could also be detected in about one half of the experimental animals. A second inoculation of virus produced a considerable augmentation of the immune response. Viral proliferation must have taken place in order to evoke this immunity, but infection always remained at the subclinical level. The results were much improved when the infecting does of virus was incorporated in an adjuvant. DPT-polio vaccine functioned well as adjuvant but equally good results were obtained with a solution of polyvinylpyrrolidone. The latter substance also has valuable properties as a protective colloid and is thus able to maintain the viability of the virus over long periods of time.

On the evidence provided by these experiments it is suggested that an adequate immunity to smallpox might be achieved in man by similar methods. A primary sensitization could be achieved by incorporating a very small amount of active virus in one of the prophylactics given as a routine in the early months of life. This could be followed by normal jennerian vaccination a few months later; or the second inoculation of virus could also be incorporated in amultivalent prophylactic. For adults, a somewhat similar two-stage immunization would be required.

It is hoped that the publication of these preliminary experiments will encourage other investigators to continue what promises to be an important line of research.

All assays involving the use of monkey kidney tissue cultures were carried out by my former assistant Mr Edmund Bischoff. His help is gratefully acknowledged.
Observations on the growth of trachoma and inclusion blennorrhoea viruses in embryonate eggs
Authors: Reeve P. , Taverne Janice
Published: May 2009

When trachoma and inclusion blennorrhoea viruses were titrated in chick embryo yolk sacs and the average day of death was plotted against dose of virus inoculated, sigmoid curves were obtained. Although all strains tested had the same growth rate, a given dose of some killed embryos more quickly than others. Strains killing most rapidly had the fewest elementary bodies per LD 50 and were the only strains to form inclusions in HeLa cells. During passage in the chick embryo three strains changed in their behaviour, killing embryos faster and acquiring the ability to form inclusions in HeLa cells.

We wish to thank our colleagues Miss D. M. Graham and Dr W. A. Blyth for allowing us to quote some of their observations and Dr L. H. Collier and Dr G. G. Meynell for their help and criticism.
Effect of various post-irradiation treatments on ultraviolet irradiatedShigella sonnei
Authors: Nakamura Mitsuru , Ramage Carol M.
Published: May 2009

More cells ofShigella sonneiwere recovered on a chemically defined medium than on complex media after the cells were irradiated with ultraviolet light. The temperature of incubation affected the numbers of colony-forming cells that could be recovered. A temperature of 37° C. yielded the largest number of colonies compared with temperature of 15, 27 and 44° C. Recovery of irradiated cells was favoured when the cells were held in buffer at 25° C. for 2½ hr. before plating on solid media.
The distribution of adenovirus antibodies in normal children
Authors: Potter C. W. , Shedden W. I. H.
Published: May 2009

The levels of neutralizing antibody against several adenovirus serotypes were determined on 42 paired specimens of maternal and cord serum and on 197 single serum specimens from children up to the age of 8 years.

The antibody distribution indicates that adenovirus infection is endemic in Sheffield just as it has been shown to be endemic in Cleveland and Washington.

We should like to thank Prof. C. P. Beattie for his advice and criticism, Dr C. C. Bowley of the Sheffield Regional Blood Transfusion Centre for paired maternal and cord sera, Dr M. H. Hambling for the provision of adenovirus stock strains and Mr Foster, medical artist, for preparation of the figures.
The effect of some antiseptic reagents on the bacterial flora of smallpox lymph
Authors: Cardone Eugene
Published: May 2009

Data are presented which amplify previously published work on the additive antiseptic effect of Roccal as follows:

1. Smallpox calf pulp derived from animals whose skin is treated with Roccal during the viral incubation period apparently adsorbs sufficient concentration of the reagent to produce a measurable bactericidal effect.

2. The adsorbed antiseptic induces a significant additive effect well beyond that of the action of stated concentrations of phenol and ether alone, as evidenced by the fact that this combination produces rapid diminution of the bacterial flora in highly contaminated calf lymph.

3. Vaccines containing the combination of antiseptics described caused no dermatitis or other untoward reactions in rabbits and humans and their viral potency was not affected.

4. The use of the antiseptic reagents makes possible the rapid preparation of smallpox vaccines for human use. Acceptable bacterial flora levels are obtained usually within 24 hr. of preparation.

The author is indebted to Magda Gagliardi, Marie Mazzochi and Izola Prunty for their assistance in the performance of the many bacterial counts, toxicity tests and other technical work.
Cleaning of hospital floors with oiled mops
Authors: Babb J. R. , Lilly H. A. , Lowbury E. J. L.
Published: May 2009

A comparison was made of three methods for the removal of dust from a hospital ward floor.

The viable bacterial counts of impression plates from the floor showed a mean reduction of 51 % after cleaning with fresh oiled mops, 40 % after cleaning with a tank model vacuum cleaner and 5 % after sweeping with a broom.

The mean proportions of airborne bacteria, compared with viable counts before cleaning, were 192 % during and 194 % after cleaning with a broom; 128 % during and 103 % after cleaning with an oiled mop, and 82 % during and 48 % after cleaning with a vacuum cleaner. On repeated use the oiled mop dispersed almost as much dust as a broom, but this settled rapidly from the air.

The effects of these cleaning methods on counts of presumptive Staph. aureus on the floor and in the air were similar to those found in counts of total organisms.

We wish to thank Mr M. D. Wilkins for valuable assistance, the Domestic Superintendent and staff and the nursing staff for their co-operation, and Messrs Leeming Brothers Limited for supplies of ‘Kex’ mops and equipment.
Liberation of organisms from contaminated textiles
Authors: Rubbo Sydney D. , Saunders Jane
Published: May 2009

By using a specially designed apparatus it was possible to study the yield of airborne organisms when various hospital textiles, artificially and naturally contaminated, were shaken under reproducible conditions. The results indicated that contaminant organisms are most effectively liberated when a textile is shaken in contact with a second fabric. The yield of airborne organisms was approximately doubled under the conditions used. Similarly, a 95 % removal of surface con taminants was also demonstrated by shaking in contact with a second textile, compared to 52 % removal when the textile was shaken alone.

These findings confirm those described in an earlier study of the spread of air borne organisms in a ward environment. It is suggested that this increase in aerial spread of infectious particles, previously referred to as a ‘counterpane effect’, is due to friction between the contaminated textile and its covering material.

Other points which emerged in the course of this work were the demonstration that cotton blankets tended to yield higher airborne counts than woollen ones and that the size distribution of bacterial particles dispersed by textiles is the same as that of the particles which contaminate the textiles.

It is with pleasure that we acknowledge the encouragement and advice of Prof. Walsh McDermott, in whose Department at the Cornell Medical College, New York, this work was carried out. We are also grateful to the National Institutes of Health, Bethesda, for financial support under Grant No. E-635(C 7).
Mycoplasmas in cell cultures from rheumatoid synovial membranes
Authors: Fraser K. B. , Shirodaria P. V. , Haire Margaret , Middleton D.
Published: May 2009

Ten strains of myocoplasmas were recovered from cultures of synovium or cultures inoculated with synovial fragments from rheumatoid arthritis and one from osteo-arthritis. The source of the organisms is not known. Patients with rheumatoid arthritis had no complement-fixing antibody and no fluorescent staining antibody against the mycoplasmas isolated and no mycoplasma antigen was detected by immunofluorescence in sections of synovia and in synovial fluids.

The strains isolated were of two main serological types and could be distinguished by direct fluorescent antibody staining from standard types of human commensals and the common tissue-culture contaminants. One may beMycoplasma laidlawii.
The toxicity of chlorophacinone and warfarin to house mice (Mus musculus)
Authors: Lund Mogens
Published: May 2009

Individually caged house mice (Mus m. musculus) were fed 0·025% warfarin (3(2-acetyl-l-phenylethyl)-4-hydroxycoumarin) or 0·025% chlorophacinone (2-(l-(p-chlorophenyl)-l-phenyl) acetyl-l,3-indandione) for periods varying from 1 to 21 days. In all, 320 mice, 160 of each sex, were tested.

A significant difference was found between the mortalities obtained by the two compounds. In feeding periods varying from 1–5 days chlorophacinone produced a mortality of 60–85 % and warfarin only 5–75 %. Five per cent, however, did survive 21 days feeding on each compound.

A great variation in the susceptibility of individual mice was established for chlorophacinone as well as for warfarin.