bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies in the dynamics of disinfection
Authors: Jordan R. C. , Jacobs S. E.
Published: May 2009

1. Disinfection curves obtained from data on the action of phenol onBact. coliat 35° C. under conditions such that unfavourable circumstances, other than the presence of the germicide, were as far as possible eliminated, have been used for the calculation of the concentration exponent for phenol, i.e.nin the formulaCnxt=K.The death-rate was not constant throughout the germicidal process but showed initially a phase of slow but increasing death-rate which merged gradually into a phase which was treated (for reasons given) as one of constant rate. This was also the maximum rate for any given phenol concentration.

2. The virtual sterilization times (v.s.t.'s), i.e. the times in min. required for the mortality to reach 99·999999 % as determined by slight extrapolation of the log survivors-time curves, the 99·9 % mortality times and the 99 % mortality times could all be used for the calculation of values ofnfor phenol as they all gave satisfactory linear relations between log concentration and log time.

3. The 50 % mortality times did not show a satisfactory linear relation between log phenol concentration and log time over the full concentration range, and at this mortality level the concentration exponent appeared to increase for concentrations above 4·62 g. phenol per 1.

4. The value ofnvaried according to the mortality level chosen. It was 5·8421 ± 0·1876, 6·6062 ± 0·2034 and 6·9638 ± 0·2164 when thev.s.t.'s,99·9 % mortality times or 99 % mortality times were used. The differences between the first and second and first and third values are significant, but that between the second and third values is not. The value calculated from thev.s.t.'sis regarded as being the most important.

5. Evidence was obtained that, as expected on theoretical grounds,nincreases for very low concentrations of phenol. If the aberrant value obtained at the lowest phenol concentration be omitted from the calculations, the value ofncalculated from thev.s.t.'s becomes 5·6588 ± 0·1422, but the decrease is not significant.

6. The maximum death-rate was related to the phenol concentration according to the expression km= 9·1743 × 10−6C5·0752, wherekmis the maximum (logarithmic) death-rate per min. andCthe concentration of phenol in g. per 1.
Studies on the disinfecting action of hypochlorous acid gas and sprayed solution of hypochlorite against bacterial aerosols
Authors: Elford William J. , Ende Joan Van Den
Published: May 2009

These studies, carried out during the period 1940–2, were undertaken to test the relative merits of hypochlorous acid gas and sprayed solutions of sodium hypochlorite, when these systems are used as aerial disinfectants, and to ascertain the factors determining their efficiencies in this capacity. The ulterior motive was the use of such systems as a counter measure against the danger of air-borne infection. The more practical aspects of their large-scale application, in shelters and other compartments, have been the province of others of our colleagues and will be reported upon separately.
An analysis of the complement-fixation reaction in influenza
Authors: Hoyle L.
Published: May 2009

1. An analysis of the complement-fixation reaction in influenza has been made by the use of chess-board experiments in which serial dilutions of antigen are tested against serial dilutions of serum with a constant dose of complement.

2. The reaction has been shown to be a complex one, involving two different antigens, the virus elementary body and the soluble antigen.

3. The soluble antigens of all strains of influenza virus A are identical, and different from the antigen of virus B.

4. The elementary body is a complex of several different antigens, and differences in antigenic structure can be detected between different strains of virus A. All elementary body preparations, however, contain soluble antigen which may be an intrinsic part of the elementary body or may be adsorbed.

5. The most suitable antigen for use in epidemiological studies is one containing chiefly soluble antigen, and a description is given of the method of preparation and use of such an antigen derived from infected mouse-lung tissue.

The author wishes to express his indebtedness to Dr C. H. Andrewes for some of the strains of influenza virus used in this work.
The isolation of Salmonella thompson from outbreaks of disease in chicks
Authors: Gordon R. F. , Buxton A.
Published: May 2009

During the years 1943 and 1944 S. thompson, not hitherto reported in poultry in this country, has been isolated on forty-four occasions from thirty-one outbreaks in chicks, and two outbreaks in ducklings. Two extensive outbreaks are described in detail, and the epidemiology of the disease and its possible importance to public health are discussed.

We wish to record our appreciation of the help given by the late Dr R. B. Haines and by Miss E. M. L. Elliot, Ministry of Food, Department of Pathology, Cambridge, in the identification of some of the strains isolated from outbreak no. 1, and for the gift of a stock strain of S. thompson which was used in the typing of strains 2768 and 3845.

We also wish to thank Dr Joan Taylor, Emergency Public Health Laboratory, Oxford, for supplying us with factor 5 (absorbed) serum.
Warm-stage observations on the development of pseudo-mycelia in cultures of avian tubercle bacilli grown in dilute embryo extract
Authors: Brieger E. M. , Fell Honor B.
Published: May 2009

1. Avian tubercle bacilli were grown in hanging-drop cultures in embryo extract prepared as for tissue culture, but diluted to 25–5% of its usual concentration.

2. Microscopic branching colonies of pseudomycelia developed in the surface film of the hanging drops during the first few days of incubation, after which growth declined.

3. The development of these colonies was studied on the warm stage and proceeds as follows:

(a) The original rods elongate into filaments.

(b) The filaments multiply by ordinary fission and also by forming fine, pin-like terminal sprouts which grow into independent bacilli.

(c) After division the daughter filaments usually remain in contact at the site of fission; their terminal growth continues at an angle to the former cleavage plane and the colony thus acquires its characteristic branching structure.

(d) The colony enlarges and ramification becomes increasingly complex until about the fifth day of incubation when growth declines. The bacilli remain filamentous.

4. When transferred to embryo extract of normal concentration the pseudomycelial colonies revert to the ‘standard’ type of development characteristic of the more concentrated medium, i.e. they pass through a phase of filamentous proliferation followed by disintegration of the filaments into short discrete rods.

5. The development of a pseudo-mycelium is compared with the three common types of growth previously seen in more concentrated embryo extract.

6. The results of this investigation shed light on the controversial question of whether the ‘mycelial’ form of the tubercle bacillus is a single individual formed by ‘true’ lateral budding or a composite structure produced by the terminal, angular growth of coherent but independent bacilli. Our observations on the living organisms have shown that under appropriate experimental conditions both these forms may develop.
The differentiation ofStreptococcus cremorisandStreptococcus lactisby means of bacteriophage action
Authors: Hunter G. J. E.
Published: May 2009

1. A series of lactic streptococci which were almost all capable of clotting milk in 24 hr. at 22°C. were divided into two groups on the basis of a few simple biochemical and morphological tests. The two groups corresponded to what some workers consider to be the speciesStr.lactisandStr.cremoris.

2. A series of phage races were tested for their action on the streptococci under various temperature and growth conditions.

3. The characteristics of phage attack on the organisms tended to confirm the division intoStr.lactisandStr.cremorisspecies. Each of the strains of the long-chainedcremoristype was attacked by only a few phages at the most, sometimes by a single phage only, whereas each of thelactis(short-chained) strains was attacked by a variety of phages. Furthermore, with two exceptions, the phage attacking thecremoristypes on the one hand and thelactistypes on the other formed quite separate and distinct groups.

4. None of the phages acted upon the several available strains ofStr.faecalisand other group D (Lancefield) streptococci.

5. The evidence obtained from the phage sensitivity tests seems to justify the division of the lactic streptococci into two species,Str. lactisandStr. cremoris.

The author is indebted to Dr H. R. Whitehead for his interest in this work, and for helpful criticism and advice.
The growth of bacterial colonies and their viable population
Authors: Mayr-Harting Anna
Published: May 2009

The numerical aspects of bacterial growth have hitherto been investigated chiefly in fluid media and the laws governing the development of bacterial populations in fluid cultures are known in some detail.
A comparative study of phenolized and alcoholized T.A.B. vaccines
Authors: Drysdale A.
Published: May 2009

1. A comparative study of alcoholized and phenolized T.A.B. vaccines has been made.

2. No difference could be detected in the immunological potency of the two vaccines.

3. The contentions of Felix and others that the reactions with alcoholized vaccine are less severe and ‘Vi’ response greater than with phenolized vaccine are confirmed.

4. The change over of large scale production in the Sudan from phenolized to alcoholized vaccine is not considered justifiable.

I wish to record my grateful thanks to Dr E. S. Horgan, Assistant Director Research, Sudan Medical Service, for the help and advice given in the carrying out of these experiments and preparation of this paper and also to Col. H. T. Findlay for his helpful criticism and permission to quote the conclusions of his preliminary experiments.
Nutritional deficiency and resistance to infectionThe effect of caloric and protein deficiency on the susceptibility of rats and mice to infection withSalmonella typhi murium
Authors: Guggenheim K. , Buechler Edith
Published: May 2009

1. The effect of either or both caloric and protein deficiency on the susceptibility of rats and mice to peroral infection withSalmonella typhi muriumwas studied.

2. Moderate restriction of food intake (80% of normal diet) for a period of 5 weeks was without influence on the infection susceptibility of rats, even when the diet fed was low in protein.

3. Long-term restriction of food intake (10 weeks) led to a marked lowering of the resistance of rats to the infection, there being a direct relation between the magnitude of the intake restriction and the extent of the resulting loss of resistance.

4. The infection resistance of rats was lowered more markedly by a given total restriction of food intake, when the latter was imposed in the form of a gradually reduced ration, than when it was imposed in a uniformly restricted ration. The effect so produced was independent of the protein content of the diet.

5. The effect of gradual food restriction was diminished by gradual supplementation of the diet with non-proteins and was augmented by gradual supplementation of the same diet with protein.

6. In mice kept on a restricted diet loss of resistance toS. typhi muriumhas been shown to be due to a deficiency of both calories and protein.
The nature of somatic phase variation and its importance in the serological standardization of O-suspensions of Salmonellas for use in the Widal Reaction
Authors: Hayes William
Published: May 2009

1.Phase variation of the somatic antigen I inBact. paratyphosumA and of the component XII2inBact. typhosumand British strains ofBact. enteritidishas been confirmed.

2. Strains ofBact. enteritidisisolated in India by blood culture from cases of invasive disease in man fall into two serological types, neither of which undergoes demonstrable somatic phase variation.

3. The probable mechanism of this type of variation is discussed in the light of experimental findings.

4. The effect which phase variation may have on the clarity of end-points in agglutinin titrations and on the serological standardization of Salmonella O-suspensions is demonstrated.

5. The variation is briefly discussed from the points of view of Salmonella philogeny and of human Salmonella infection.

I am indebted to the D.M.S. in India for permission to publish this paper.
Craigie's Vi phage method and South African strains ofB. typhosus, with special reference to typhoid carriers
Authors: Crocker Clarice G.
Published: May 2009

The work began with efforts to isolate a type II Vi phage from local sewage. When this attempt failed, typing material was obtained from Dr J. Craigie and Dr A. Felix.

The typing method was applied to 495 strains of typhoid bacilli, the technique laid down by Craigie being followed throughout.

It was found that in South Africa the distribution of the various types of typhoid bacilli is different from that obtaining in other countries where this typing method has so far been applied.

During further investigations of type F strains the fact came to light that by means of a simple biochemical test type F strains can be subdivided into two sub-types, which subdivision will be useful in further epidemiological work. No such biochemical subdivision was found possible in any other type.

It did not prove possible to type all South African strains with the available phage preparations. Some of these strains must represent new types. Workers in other countries have had similar experiences and it will become necessary to compare all these unusual strains directly with one another in order to reach uniformity in nomenclature. It has already been possible to co-operate with workers in England, and they have been assisted by my finding that a strain, unique in England and supposed to have been brought there by a carrier, who had typhoid fever in South Africa 40 years ago, was endemic in South Africa.

During the course of the work, two outbreaks of typhoid fever occurred in which the typing method proved most useful, not only for linking up a particular carrier with a particular outbreak, but also for excluding an already known carrier who was under grave suspicion.

I have to thank Dr Craigie and Dr Felix for supplying material, and Prof. Pijper, of the Pretoria University, for placing laboratory facilities at my disposal. I thank all others for cultures received for typing.
Fatal meningitis due to a capsulated Neisseria
Authors: Christie A. L. M. , Cook G. T.
Published: May 2009

In this paper a fatal case of meningitis is reported in which a capsulated Diplococcus of the Neisserian group was isolated from the purulent cerebrospinal fluid. A capsulated Gram-negative Diplococcus growing readily on agar was isolated from the nasopharynx and the cerebrospinal fluid by von Lingelsheim (1906, 1908) and called by him D. mucosus. Similar organisms were also isolated from the nasopharynx by Elser & Huntoon (1909). Cowan (1938) reported two cases operated on for cerebral tumour in which D. mucosus was grown from the cerebrospinal fluid. These strains were regarded by him as contaminants setting up a low-grade infection in a brain which, exposed for operation, offered little resistance to infection. Two cases of meningitis due to a capsulated Diplococcus have been reported by McFarlan (1941) and Bray & Cruickshank (1943); both these patients responded well to sulphapyridine and recovered. Edwards (1944) described a fatal case of meningitis due to an atypical Neisseria which in many respects resembled D. mucosus, although it was not capsulated. The rarity with which capsulated Neisseriae are associated with pathogenicity is considered sufficient justification for reporting the following case.
Feeding and breeding of laboratory animals
Authors: Bruce H. M.
Published: May 2009

1. Breeding records are given of fourteen female Dutch rabbits reared and maintained without green food, and of twelve of their female offspring.

2. Fertility, average litter size at birth, and the percentage of young weaned, were good for the breed.

3. No difference in growth rate was found between the first and second generations of young.

4. With the dry pelleted diet, supplemented by drinking water, fresh green food is unnecessary for breeding rabbits, as it has already been shown to be unnecessary for growing animals (Bruce & Parkes, 1946).

I should like to thank Dr A. S. Parkes, F.R.S., for his help in the preparation of the manuscript.
Improved guns for the delivery of liquid D.D.T. spray and powder by mechanical compressors
Authors: Gordon I.
Published: May 2009

On the basis of experience in using D.D.T. as an insecticide in both liquid and powder forms, suggestions are made for improved spray and dust guns.

My thanks are to S./Sgt. Toop, workshop foreman, and Pte Carter, tinsmith, of my old hygiene section, for the months of experiment, trial and error involved in producing these apparently simple innovations. Also to Brigadier H. B. F. Dixon, D.D.M.S. West Africa Command, for permission to forward this article for publication.
A survey of tuberculosis in the industrial county of Lanarkshire, Scotland
Authors: Brown T. Gow
Published: May 2009

In this investigation the hitherto unexplored field of tuberculous Lanarkshire has been surveyed.

The relative incidence of human and bovine strains of the tubercle bacillus in 80 cases of pulmonary tuberculosis and in 311 cases of extrapulmonary tuberculosis has been examined. Results have shown that bovine infections were present in 2·5% of the pulmonary cases, a figure that is in keeping with the expected incidence for an area as highly industrialized as Lanarkshire.

The extrapulmonary strains have been further subdivided into 165 strains isolated from patients suffering from tuberculous meningitis, 72 strains isolated from patients with cervical adenitis and 74 strains from patients with tuberculous lesions affecting bone or joint. Each group has been analysed separately.

In the 165 cases of tuberculous meningitis bovine infections accounted for 28·5 % of the total. This figure was slightly higher than the 22% given by Blacklock & Griffen (1935) for the Glasgow area and the 24% of Macgregor & Green (1937) for the Edinburgh area, but it was lower than the 36% found by Munro & Scott (1936) in the east of Scotland and the 40·5% given for Scotland by Griffith (1934) in his general survey. The greater preponderance of bovine infections in rural areas supported the observations of these workers.

The cervical adenitis group gave the percentage of bovine infections as 30·4, a result much lower than any previously published for Scotland, but there can be no doubt that a family history of pulmonary tuberculosis obtained from 50 % of the patients in the industrial group who supplied human strains must have been a most important factor in influencing the relative incidence of the two types of tubercle bacillus. There were 72 cases of cervical adenitis investigated and 52 came from the industrial area.

Seventy-four patients suffering from tuberculous lesions affecting bone or joint gave a bovine incidence of 18·9%, a percentage that is lower than that given by Munro & Cumming (1926) of 36·4% but approximating to the 20·5% given by Wang (1917) for the Edinburgh area. Munro & Cumming were dealing with a less industrialized area than Lanarkshire which probably accounts for the variation as also does the fact that, of 7 human cases occurring in the rural part of Lanarkshire, 5 gave a family history of pulmonary tuberculosis.

These figures only serve to substantiate observations of regional variation and endorse the findings of other workers who have found a lower proportion of bovine infections in industrial districts. As Lanarkshire is the most highly industrialized county in Scotland it was to be expected that the results of this investigation might have given an even greater predominance of human infection than actually was found.
The influence of social factors on the incidence of extrapulmonary tuberculous infection
Authors: Brown T. Gow
Published: May 2009

An investigation into the probable influence of environmental factors on the incidence of extrapulmonary tuberculous infections and into the possible explanation of their effect on regional differences in the proportional frequency of the type of infecting strain of the tubercle bacillus has been described.

The importance of substandard housing and of family history in infection with the human type of the tubercle bacillus, particularly in children, has been noted.

Circumstantial evidence of both low economic resources and milk supply influencing infection with the bovine type of the tubercle bacillus pointed to these factors being important in childhood.

I wish to acknowledge the co-operation I received from the Medical Officers of Health for the several Local Authorities within the county of Lanark.
Isolation and maintenance of an L1-like culture fromFusiformis necrophorus(Syn. Bact. funduliforme, Bacteroides funduliformis)
Authors: Klieneberger-Nobel Emmy
Published: May 2009

The studý of theFusiformis necrophorusculture ‘132’ showed that new pure LI cultures could be isolated from it, which have already been maintained for one year and undergone more than 100 passages without reverting to their original type. The new cultures resemble the old L 1 strains fromStreptobacillus moniliformisin every respect except for their strict anaerobiosis. It has been observed that swellings of the bacteria develop into large bodies not distinguishable from the elements of which the pure L 1 culture consists.

In the light of the new observations onFusiformis necrophoruswhich are in full agreement with those of Dienes & Smith it is still not possible to disprove the symbiosis theory, for the newly established L 1 cultures have not reverted so far. Secondly, though it has been seen that L 1 forms develop from swellings of bacteria, the possibility that a parasite might behave in a similar way cannot be excluded.

On the other hand Dienes's opinion of the bacterial nature of the L 1 component cannot be disproved either. However, we know yet too little about the normal developmental cycle of bacteria to be able to decide whether the L 1 form is an independent entity or whether it may be a normal stage through which bacteria have to pass from time to time or whether it may represent a ‘loss-mutant’ which some bacteria might produce under not yet known conditions. If in the future the bacterial nature of the L1 could be convincingly proved we would be faced with the fact that bacteria can assume a form in which they grow as a thin shapeless slime containing nuclear structures arranged as bodies, rings or very finely dispersed particles—not the dumbbell pattern so characteristic for young bacteria of all kinds—and that further very small parts of the material (filterable granules?) are able to reproduce the L1 culture which at least can go on for many years without reverting into the bacterium from which it was derived.
Inhibition of bacterial growth by pure ozone in the presence of nutrients
Authors: Ingram M. , Haines R. B.
Published: May 2009

Data are given showing the concentration of pure ozone required to inhibit the growth of, and to destroy, various micro-organisms when growing on agar, in nutrient broth, a synthetic medium, or simply suspended in water. The following is shown:

1. Different organisms vary in their susceptibility towards this gas. Achromobacter and Pseudomonas strains, such as occur on chilled meat, are the most resistant. On the whole, mould fungi are about as susceptible as bacteria.

2. Very much higher concentrations are required to arrest established growth than can be used if inoculation and admission of inhibitor are coincident.

3. Lower concentrations are inhibitory at lower temperatures. These results are ascribed to dissipation of the ozone by combination with products of bacterial metabolism. It seems that any factor which diminishes growth will augment the effectiveness of ozone.

4. Comparatively small concentrations (less than 10 p.p.m.) suffice to destroy bacteria suspended in water. Somewhat larger concentrations inhibit growth in a synthetic medium.

5. Still larger quantities (several hundred p.p.m.) are required in nutrient broth.

6. Nutrient broth treated with ozone will support little or no bacterial growth, due to change of pH, growth taking place slowly if the pH is restored to its original value. Inhibition of growth in such a medium is therefore a complex process depending in part upon the secondary effects of decomposition of the medium.

7. To kill them, bacteria require still more ozone (in some cases several thousand p.p.m.) if growing on agar. These results are ascribed to combination of ozone with the supporting medium.

8. When applied to organisms growing on food, combination with ozone not only spoils the food, but it makes it difficult to interpret the effect on the microbes in terms of the ozone applied.

9. The inhibitory concentrations are higher than humans can tolerate.

10. Ozone destroys the dehydrogenating enzymes of the cell, and it is suggested that its germicidal action may be partly due to interference with cellular respiration.

The work described in this paper was carried out as part of the programme of the Food Investigation Organization of the Department of Scientific and Industrial Research.
Feeding and breeding of laboratory animals. X. A compound diet for monkeys
Authors: Short D. J. , Parkes A. S.
Published: May 2009

1. The use of compound cubed diets for monkeys is discussed.

2. Experiments are described which seem to show that a cubed diet, supplemented only by greenfood and water, can be completely adequate for growth and reproduction.
A study of herpes zoster particularly in its relationship to chickenpox
Authors: Seiler H. E.
Published: May 2009

The results of a field survey of herpes zoster over a period of 18 months are described and the difficulties of such a survey mentioned.

A total of 246 patients with herpes zoster, only 16% of whom had attended hospital, is reported. It is calculated that the yearly incidence in the population was approximately 2 per 1000.

Full investigation and ‘follow up’ was undertaken in 184 cases. These are classified according to the site of the zoster—the dorsal, supra-orbital and cervical regions being affected in almost 90%, the dorsal region alone accounting for 53·3%.

Herpes generalisatus occurred in 7, or 38%, of the cases, recurrent herpes zoster in 6, or 3·3%, while there was one case of motor paralysis affecting lower limb.

The majority of patients were apparently well at the onset of the zoster, but 27 had some associated disease; 5 gave a history of trauma prior to the onset and 2 were related to pregnancy.

The seasonal and geographical distribution is given and, while the numbers are too small for statistical analysis, the disease in 1947 showed two peaks of higher incidence, the one in May and the other in October. Crowding or density of population did not appear to be important, and the disease occurred sporadically rather than in epidemic form.

There was a higher proportion of female cases, but when related to the population as a whole no sex differentiation was observed. Of the patients 60% were over 45 years of age.

There was no evidence that housing conditions or occupation were of aetiological significance or that the disease was more common among any particular section of the community.

Eleven patients had been associated with other cases of herpes zoster before developing the disease, while 3 gave a suggestive history of prior contact with chickenpox.

A condition indistinguishable from chickenpox occurred among the contacts of 10 patients, 12 individuals being affected, and there was one instance of concurrent herpes zoster and chickenpox. Other infections such as mumps, measles and rubella, while as common in association with the onset of herpes zoster, were not so frequently found as the chickenpox condition amongst contacts of the disease.

The results of the survey as regards the relationship of chickenpox and herpes zoster are discussed. It is considered that the evidence does not favour a significant association with chickenpox prior to the onset of herpes zoster, but that the facts are consistent with the view that a condition indistinguishable from chickenpox may follow contact with herpes zoster. It is suggested, however, that this may be a generalized manifestation of the virus of zoster rather than true chickenpox.
Glycine and formic hydrogenlyase
Authors: Gordon J. , Stickland L. H.
Published: May 2009

1. A strain ofBoot, coliadapted to growth in high glycine concentrations, which had lost the power of producing ‘gas’ from sugars, was shown to be devoid of formic hydrogenlyase.

2. Formic acid was prominent among the products of fermentation of sugars by this strain.

3. The appearance of formic hydrogenlyasein vitro, in bacteria grown in such a way as not to contain the enzyme, was inhibited by glycine at high concentrations.

One of us (J. G.) is indebted to the Medical Research Council for a grant-in-aid for expenses.
The relative viability of human spermatozoa
Authors: Crooke A. C. , Mandl Anita M. , Irwin J. O.
Published: May 2009

A heterogeneous sample consisting of eighteen specimens of semen provided by eleven patients was examined. Smears were supravitally stained at 3, 8 and 27 hr. Counts of living and dead spermatozoa, classified into normal and fourteen types of abnormal forms, showed that whereas five abnormal forms were always dead, the remaining types showed varying proportions of dead and living cells. Their rate of mortality was somewhat greater than that of normal spermatozoa.
Destruction of bacteria in sewage and other liquids by chlorine and by cyanogen chloride
Authors: Allen L. A. , Brooks Eileen
Published: May 2009

When samples of domestic sewage are treated with doses of chlorine lower than the chlorine demand bactericidal action depends not only on the proportion of the demand satisfied but also on the absolute size of the dose. With doses just sufficiently large to leave residual chlorine detectable byo-tolidine, reduction in the plate count of bacteria after contact for 15 min. ranged in various tests from 96·2 to 98·7%.

With domestic sewage reduction in bacterial count after addition of chlorine is followed, after an interval, by aftergrowth of survivors which rapidly brings the population to its original level or higher. For this interval to be prolonged the initial concentration of chlorine must be considerably greater than the chlorine demand. This accords with the fact that the rapid reaction of chlorine with constituents of the sewage, which occurs in the first few minutes, is followed by a slower absorption which takes place over a prolonged period, so that the initial bactericidal action of residual chlorine tends to be lost after a time. For many purposes the effectiveness of chlorination should be judged not only by the percentage of bacteria destroyed after a short period of contact but also by the interval which elapses before aftergrowth becomes appreciable.

In samples of sewage treated with doses of chlorine sufficient to destroy the protozoa, surviving bacteria eventually reached a level of population much higher than that of the untreated sewage. The majority of such bacteria were found to be Gram-negative, non-sporing rods, which included strains ofProteusand ofPseudomonas pyocyanea. Tests with a pure culture of a species ofProteusshowed that the organisms surviving chlorination are not intrinsically capable of reaching a higher population than the parent culture.

When sewage contains small quantities of gas liquor or thiocyanate the bactericidal action of doses of chlorine lower than the demand is much more prolonged than the action of comparable doses in domestic sewage, owing to the formation of cyanogen chloride.

Comparative tests of the action of chlorine and of cyanogen chloride on pure cultures ofBacterium coliin peptone water and on the mixed flora of sewage showed that the bactericidal effect of cyanogen chloride was more persistent than that of a comparable dose of chlorine. With sewage and with some brands of peptone the immediate effect of the chlorine, on the other hand, was often considerable.
Differential diagnosis of vesicular stomatitis and foot-and-mouth disease. Examination of virus samples from Mexico with special reference to complement fixation
Authors: Brooksby J. B.
Published: May 2009

The usefulness of the complement-fixation test in differential diagnosis between vesicular stomatitis and foot-and-mouth disease has been demonstrated on two ‘field’ specimens of virus from Mexico. Examples are given of the practical applications of the other methods for this differential diagnosis.
The survival of bacterial in dust. IV. Atmospheric humidity and the bactericidal action of ultra-violet irradiation
Authors: Lidwell O. M. , Lowbury E. J.
Published: May 2009

The bactericidal effect of ultra-violet radiation on dried films of β-haemolytic streptococci has been shown to be dependent both on the relative humidity and on the nature of the suspending medium from which the films are prepared. In particular, while the bactericidal action is most often more repaid under dry conditions, films prepared from suspensions in dust extract culture show a similar behaviour to that of naturally occurring dust flora and are most resistant to the effects of radiation under dry conditons.
Poliomyelitis in Auckland, 1947–1949. An epidemiological study
Authors: Thompson A. W. S.
Published: May 2009

(a) This paper is a study of a poliomyelitis epidemic in the Central Auckland Health District which commenced in November 1947, and by the end of April 1949 had produced 345 cases in a population of about 350,000.

(b) Incidence per 10,000 reached 8·0 in the city, 15·4 in the country districts, and 21·5 in certain urban areas lying between city and country.

(c) In general, incidence was inversely related to population density. Abnormally high incidences in some urban areas was attributed to influx of rural dwellers in recent years. Unusually low incidence in one city area may have been related to the periodic effect of race meetings in increasing the local density.

(d) The three previous Auckland epidemics showed a successively declining incidence, and were linked by periods of grumbling activity. The present epidemic was preceded by a lull, and its toll has approached that of the 1916 epidemic. It is probable that a new cycle has begun which will imitate the first, but on a lower scale.

(e) Spot maps showed that the disease was already widespread before the first positive cases revealed its presence. Some ebb and flow, but no actual movement from one area to another, occurred during its course. An interesting feature was the comparative rarity of cases in the neighbourhood of the city's sewage-polluted bathing beaches.

(f) An inverse correlation was noted between the ratios of ‘suspect’ to positive cases established in a previous inquiry, and the incidence of cases with paralysis or paresis in various age/sex groups. High ratios indicated lower severity.

(g) It was estimated that by the end of April 1949, all boys 10–15 years in Auckland had been affected by poliomyelitis, either ‘suspect’ or positive. Less than half the girls of this age had been affected. Estimates are given for the other age groups.

(h) Families of cases showed no significant difference in composition from the average in the area.

(i) No correlation, whether inverse or direct, was found between sanitary conditions in schools and the incidence of positive cases.

(j) The cycle of poliomyelitis in the community is discussed in the light of these findings.
Plague in Java, 1910–1912
Authors: Swellengrebel N. H.
Published: May 2009

I Know that you have finished your study in tropical medicine and hygiene at this school. And so, surely, I am not wide of the mark if I suppose there is very little in the way of facts and views you have not, at least, heard of. I think it rather useless to try to add one more small fact, or one more insignificant view, to the hoard of knowledge stored in your brains, or in your notebooks.
The action of dicoumarol on laboratory and wild rats, and its effect on feeding behaviour
Authors: Armour C. J. , Barnett S. A.
Published: May 2009

The behaviour of wild rats towards an unfamiliar food presents problems of both practical and theoretical interest (Chitty, 1950; Shorten, 1950; Thompson, 1948). When first eaten the food is often taken in very small amounts; if poison is present its effects soon make the rats stop feeding, and if they recover the rats are often found to bebait-shy; that is, they refuse the bait entirely (Rzoska, 1950). As far as rat control is concerned prebaiting with harmless food can overcome this difficulty by inducing rats to feed rapidly on the bait when poison is eventually added (see Barnett, 1948, for a review); and if there are even then a few bait-shy survivors they may be disposed of by a second prebaiting and poisoning with different materials. In large-scale practice, however, this elaborate programme presents considerable difficulties for organizations such as local health authorities, and they are often unable to adhere to it.
Feeding and breeding of laboratory animals. XI. Vitamin E deficiency in mice on a diet containing 85% of whole-grain cereals, after the addition of 2% of cod-liver oil
Authors: Bruce H. M.
Published: May 2009

The appearance of vitamin E deficiency in rats and mice after the introduction of 2% of cod-liver oil to a diet containing 85% of whole-grain ground cereals is described. Evidence is given to show that the deficiency can be prevented by the reduction of the cod-liver oil content to 1%.
Accidents among children under two years of age in Great Britain
Authors: Rowntree G.
Published: May 2009

1. In the spring of 1948 the health visitors of 422 authorities in Britain obtained information from 4683 mothers on accidental injuries sustained by their young children during the first 2 years of life. This study formed part of a questionnaire inquiry into the health and development of these young children, who had all been born in one week, 3–9 March 1946.

2. The mothers seem to have remembered accurately the more serious accidents which received professional treatment during the 2 years under review. It is possible that some of the minor injuries which had not been treated were not recalled or entered on the questionnaires.

3. The rate for all serious injuries which received professional care was 79·6 per 1000 children in the sample. Treated cuts were almost as frequent as treated burns or scalds, each being sustained by about 37 per 1000 children. There were only 7·5 fractures per 1000 children. The sum of the rates for each type of injury (81·3 per 1000) slightly exceeds the combined rate for all children injured (79·6 per 1000). This is due to the fact that in calculating the former rates eight children who were each involved in two serious accidents of different types were counted twice, i.e. once under each type of injury sustained.

4. In 1946–8 treatment of young children for burns or scalds and for serious cuts was most frequently given by general practitioners. Children under 2 years of age were admitted to accident wards of hospitals chiefly for the treatment of serious burns or scalds. Fractures were usually treated at out-patients’ departments.

5. Although almost all accidents occurred at home, variations in housing conditions, as measured by crowding and the domestic facilities available, had little effect on the incidence of accidents among children under 2 years of age. Accidents happened most frequently when the children were beginning to walk and becoming inquisitive, and most injuries occurred either because they were not steady on their feet or because they had not developed ‘heat-sense’.

6. Since domestic help was rare, most children had to play in the kitchen or living room while their mothers were doing the housework, cooking and laundry. In these circumstances, they were often exposed to the risk of injury.
Feeding and breeding of laboratory animals. XII. A note on the breeding of guinea-pigs without fresh green food
Authors: Bruce H. M.
Published: May 2009

1. Five generations of guinea-pigs bred successfully on diet 18 supplemented with crystalline ascorbic acid but without fresh green food.

2. No difference in reproductive performance was found between these animals and those of the normal breeding colony receiving unlimited supplies of fresh abbage.

3. Symptoms of vitamin E deficiency appeared among some young of the fourth and fifth generations, showing that diet 18 alone contained barely enough of this factor for continuous reproduction througy many generations.

4. Diet 18, supplemented by hay and fresh green food to supply vitamin C and additional vitamin E, provides all the essential factors required by the guinea-pig.
The rapid detection of Mycobacterium tuberculosis by microscopic examination of milk from individual cows and from groups of ten cows
Authors: Maitland Mary L. Cowan
Published: May 2009

The success of detecting Mycobacterium tuberculosis in milk by microscopic examination of samples from each quarter of the udder and the use of this method in rapidly eliminating from a herd those cows which were excreting tubercie bacilli has been reported (Maitland, 1937). The advantages from the clinical point of view with illustrative clinical data have been recorded by Locke (1937), who collaborated in the investigation.
Human tuberculosis of bovine origin in Northern Ireland
Authors: Reilly Lilian V.
Published: May 2009

A survey of the extent of bovine type human tuberculosis in Northern Ireland has been made from unselected material during the past 5 years.

Only one case of bovine type pulmonary tuberculosis was found out of more than 1000 cases.

The proportion of bovine type cases in the non-respiratory group was 4·3%; 3·3% of meningitis cases were of bovine origin.

A marked decline in the extent of bovine type infection is shown to have occurred during the past 10 years. This is believed to be due to a great increase in the pasteurization of milk during this period. Milk was a particularly valuable food during the war, and pasteurization facilitated its distribution.
The conglutination phenomenon. VII. A study of the interaction of complement components and conglutinin in the process of conglutination
Authors: Coombs R. R. A. , Blomfield A. M. , Roberts G. Fulton
Published: May 2009

Techniques for the fractionation of C′ 1 and C′ 2, and for the specific inactivation of C′ 4 of horse complement are described, and shown to be satisfactory. These three components of complement and also conglutinin are found to be essential to the process of conglutination.

The experiments reported do not exclude the possibility of additional or unidentified fractions of horse serum playing a part in the reaction. Whether or not C′ 3 is essential to the process of conglutination could not be determined from the evidence available.

It was found that by the procedures employed the C′ 4 fraction may be supplied either from the horse complement or from the heated bovine serum added as a source of conglutinin or from both.

When horse complement and bovine antibody against sheep cells are used it is found that conglutination will only result when the complement components are absorbed on to the immune complex in a particular sequence. The sequence is that C′ 1 is absorbed first on to the sensitized cells, and then C′ 2 and C′ 4 are absorbed together. Both these components must be presented together to the sensitized cells carrying C′ 1 if conglutination is to result. Finally, conglutinin acts on the sensitized cells which have absorbed the three complement components, and conglutination results.

The significance of these findings, together with matters of a more general nature, is discussed.
Observations upon the cytology and life history ofFusiformis
Authors: Morris E. O.
Published: May 2009

Fusiformisis a multicellular organism having the cytological characters of the Eubacteria, and normally reproducing by fission.

A few cells of all the strains examined pass through the L cycle; usually the initiation of this process follows the patterns described inProteusand the Morax-Axenfeld bacillus. It has not so far been possible to grow these L-forms ofFusiformisin culture without immediate reversion to the bacillary form.

The stable forms described by other workers appear to be produced by a process analogous to the sexual conjugation seen in theActinomyces.

The evidence suggests that passage through the L cycle is a normal function ofFusiformisin its natural habitat.
Some chemical and bacterial characteristics of bottom deposits from lakes and estuaries
Authors: Allen L. A. , Grindley J. , Brooks Eileen
Published: May 2009

Chemical and bacteriological examination of muds from sources differing widely in the degree of pollution to which they were subject showed great differences in the contents of carbon, nitrogen and sulphide. These differences were not correlated with differences in the severity of faecal pollution. The amount of organic matter available for growth of micro-organisms in the mud of different depths was not reflected in the figures for organic carbon. A convenient index of this factor was obtained by measuring the volume of gas evolved during anaerobic digestion over a prolonged period of incubation. The rate of evolution was increased by the addition of an inoculum of digested sludge from a sewage works.

Sulphate-reducing bacteria appeared to be of two different types. In samples of mud from fresh-water lakes much higher counts were usually obtained in a medium containing comparatively low concentrations of inorganic salts and of lactate than in a medium containing much higher concentrations of these constituents. In samples from locations where conditions were more saline the reverse was usually true.

Counts of Bact. coli and of Strep, faecalis together probably constitute the best index of faecal pollution in the examination of samples of mud. These organisms are, however, largely confined to the surface layers.
Variation in complement-fixing activity ofRickettsia burnetiduring egg adaptation
Authors: Stoker M. G. P.
Published: May 2009

1. The haemolytic complement-fixation test and the conglutinating complement-absorption test, as well as the agglutination reaction and the antiglobulin sensitization test, have been used to study a change which occurs during egg adaptation of the Christie strain ofR. burneti.

2. Antigens were prepared from yolk sacs of the third to the ninth passages inclusive. Irrespective of numbers of rickettsiae, antigens from the third and fourth passage failed to fix complement with homologous (human) antiserum, unless the latter was in very low dilution. From the fifth passage, however, antigens fixed complement with high dilutions of the same antiserum and thus resembled the classical Henzerling strain antigen.

3. Third-passage antigen failed to fix conglutinating as well as haemolytic complement with high serum dilutions. The agglutination reaction and antiglobulin test, however, showed that third-passage antigen absorbed antibody almost as well as ninth-passage and Henzerling strain antigens.

4. It was not possible to find out if the change in behaviour was due to a true antigenic variation or to non-specific hindrance of complement absorption. Heating failed to alter the behaviour of the antigens and the results of absorption tests were inconclusive.