Search

Before the foundation in 1893 of the Journal of Pathology and Bacteriology by the late Professor Sir G. Sims Woodhead, there was no English journal devoted to pathology, bacteriology and kindred subjects. In 1901 Professor G. H. F. Nuttall founded the Journal of Hygiene, the second English journal of this type, and edited it till his death in December 1937. Owing to the increasing number of papers on parasitological subjects, which he received for publication in this journal, he founded Parasitology in 1908 and was its chief editor till 1933. He was very proud of both journals, and for some years made himself personally responsible for the heavy expenses of production. Within a few years of its foundation each began to pay for itself, and afterwards both were taken over by the Cambridge University Press. [ABSTRACT FROM PUBLISHER]

The meaning of the footnote on p. 162 is somewhat ambiguous and the statement comprised in it is not true for all values of n, the number of differences in N.F.T. of which the significance of the mean is tested.The statement that, by the use of a certain approximate distribution, significance of an observation is underestimated means that the estimated value of P in the neighbourhood of the significance level is greater than the true value. [ABSTRACT FROM PUBLISHER]

In view of the great interest attached to the questions discussed in the preceding paper, and the doubt expressed therein regarding the accuracy of Schaudinn's observations on the relationship between Halteridium and Trypanosoma, it seems expedient to reprint the following short papers by Novy, MacNeal, and Torrey, and Novy and Knapp, which appeared on February 9th, 1906, in Science (vol. 23, pp. 207–208). [ABSTRACT FROM PUBLISHER]

Single and multi-jet liquid impingers and membrane-filters were found to be efficient sampling devices for aerosols generated from suspensions of the virus of foot-and-mouth disease (FMD). Concentration of the aerosol samples with an adsorbent, Attaclay, facilitated the detection of small amounts of virus. Sodium dodecyl sulphate could be used for elution as the virus of FMD is resistant to this anionic detergent.The penetration of these aerosols through various air filtration media was determined using impinger samplers. A glass fibre paper was found to be the most efficient with a virus penetration of less than 0·001%.We wish to thank Dr D. W. Henderson and Dr H. M. Darlow, of M.R.E. and Mr R. G. Dorman of C.D.E. Porton for valuable prefatory discussions and advice. We are also indebted to Miss S. Cartwright for inoculating mice, to Miss M. Shoobridge and Mr S. Taylor for technical assistance, and to Vokes Ltd. for supplying materials. [ABSTRACT FROM PUBLISHER]

No information from official or non-official sources is available on the prevalence of enteric fevers in Palestine in pre-war days. Since the establishment of the British Administration (1919) the Annual Reports of the Government Department of Health invariably emphasise the high incidence of enteric fevers. Several papers dealing with the epidemiology of the disease appeared in the Hebrew periodicals Briuth Haam and Harefuah and in 1926 an elaborate Report was submitted to the Department of Health by a Committee of Enquiry appointed by the Department to consider and advise on the situation as regards enteric fever in the country. The data thus accumulated, although very valuable for the local health authorities, did not reveal any peculiar features of more than local interest. Their publication abroad seemed, therefore, superfluous. [ABSTRACT FROM PUBLISHER]

Circumstances in connection with the recent census have again directed my attention to the laws which govern human life. I have long been of the opinion that the old ideas that birth rates and death rates had no biological relationship beyond the obvious ones, that many infants mean more deaths, etc., usually found stated in public health text books, were based on a very imperfect induction. On one aspect of this I published a paper a number of years ago in the Transactions of the Royal Philosophical Society of Glasgow (1), and last summer Sir Shirley Murphy(2) read a paper on another aspect of the same subject before the Sanitary Congress held at York. But I have hitherto refrained from publishing theories because I believe that until quantitative measures are applied no scientific results worthy of discussion can be obtained. Now that such seem to be possible, I propose to discuss in a series of papers the different relationships which I have investigated. No mathematics will be introduced in the earlier papers, but the results of all will be summarised and dealt with in their mathematical and physico-chemical relationships in a concluding communication. The first paper relates to the connection between the “corrected” death rates and the “true” death rates as found by constructing a life table. [ABSTRACT FROM PUBLISHER]

There is no official scheme for testing disinfectants and detergent/disinfectants for use in the retail food trade and few recommended procedures have been given for the cleaning of equipment with these agents. Therefore, field trials were carried out in a large self-service store. Comparisons were made of the various cleaning efficiencies, as determined by bacterial plate counts, of detergent and disinfectant solutions and machine cleaning oils applied with either clean cloths or disposable paper towels to items of equipment. The most satisfactory results were always obtained when anionic detergent (0·75 % w/v) and hypochlorite (200 p.p.m. available chlorine) solutions were applied in a ‘two-step’ procedure.Tests were made to compare the calcium alginate swab-rinse and the agar sausage (Agaroid) techniques for the enumeration of bacteria on stainless steel, plastic, formica and wooden surfaces before and after a cleaning process. Although recovery rates were always greater by the swab-rinse technique, the agar sausage technique was considered to be a useful routine control method for surface sampling. [ABSTRACT FROM PUBLISHER]

The development of the molluscum body and of the molluscum contagiosum virus is described. All cells of the molluscum lesion do not form molluscum bodies, but those which do probably show cytoplasmic abnormality prior to the appearance of virus particles within the cytoplasm. Such abnormal cells may reflect the activity of some infective precursor of the morphologically observable virus particle; they may alternatively represent cells which have successfully resisted invasion by the infective precursor.Cells which have failed to resist invasion gradually become filled with virus particles and the nucleus becomes eccentric. The molluscum body thus formed is virtually a bag of virus particles, the wall of the bag being the peripheral cytoplasm, which seems to resist invasion and in which the nucleus remnant can readily be detected.There appear to be two kinds of viruses. Development of the commoner virus is compared and contrasted with studies by Morgan and his colleagues of vaccinia and fowl pox. It is akin to fowl pox in its origin from foci of finely dispersed cytoplasm, here called cytoplasmic clouds; it is akin to vaccinia in that no evidence can be found of a denser, finely granular, pre-nucleoid material; it is like both in that the virus does not observably develop within the nucleus; and it is unlike both in that a nuclear change—the appearance of rather unspecific dense bodies—is seen. The structural changes seen in the virus particles during development are similar to those described by Morgan et al., but a slightly different interpretation is given of the behaviour of the transient ‘nucleoid’: they believe that it expands to form a central viroplasm, whereas in this paper it is believed to disperse through an already present central viroplasm.The second type of virus is of uncertain origin. It may develop from, or at least it seems to be related to, a double-membrane structure seen in abnormal lesion cells. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM PUBLISHER]

The manuscript notes from which the following Account of the Journal of Hygiene has been prepared for the press were left unfinished by Dr Graham-Smith at the time of his death on 30 August 1950. He intended that the Account should be published to mark the fiftieth year of the Journal's existence. [ABSTRACT FROM PUBLISHER]

The quantitative theory for the interaction between antigen and antibody presented in the previous paper has been compared with some experimental precipitin reactions published in the literature. These reactions include Type VIII pneumococcus polysaccharide-homologous (horse) antibody, egg albumin-(rabbit) anti-egg albumin and diphtheria toxin-(horse) antitoxin.1. The general course of the experimental precipitation curves (total amount of precipitate, amounts of precipitated antigen and antibody) corresponded well to the theoretical type curves. Hence it may be concluded that the precipitates may be composed of mixtures of compounds of the types AG, A2G, A3G, …, ANG in accordance with the law of mass action. In the cases with ‘inhibition zones’, however, AG, or ANG, or both (and perhaps several more compounds) retain the same solubility as the free antigen (G) and free antibody (A).2. With regard to the location of the ‘equivalence zones’, experiment and theory also showed a satisfactory agreement.3. A hypothesis on the velocity of flocculation in the precipitin reaction is presented and compared with some recent results. The relation between the immunological concepts ‘equivalence (neutral) point’, ‘optimum point’ and ‘maximum precipitation point’ is also discussed. [ABSTRACT FROM PUBLISHER]

In a recently published paper (Kermack & McKendrick, 1937) the observational data relating to epidemics of ectromelia in populations of mice maintained under experimental conditions (Greenwood et al. 1936) has been analysed in the light of a mathematical theory of epidemics developed by us during recent years (Kermack & McKendrick, 1927, 1932, 1933, 1936). It was shown that the life table giving the chance of mice surviving for various lengths of time in infected communities is very closely represented by a formula calculated on the assumption that the various rates—infection rate, recovery rate, death rate, etc.—are constants. It is, of course, realized that this simplifying assumption can only be regarded as approximately true. It renders the application of the general theory practicable, and the result of the investigation justifies its use, in so far as the theory so simplified does actually conform to the experimental results. [ABSTRACT FROM PUBLISHER]

For some years one of my principal interests has been to study, in collaboration with my colleagues, E. M. Newbold, W. W. C. Topley and J. Wilson, the epidemiological phenomena observable in communities of mice exposed to risk of infection. In this work we have often found it convenient to summarise part of our results under the form of what we call a Life Table. We treat the entrants to our communities as live-births and determine the rate of mortality prevalent in the community over a certain epoch for each day of life, in the familiar life-table form. The result has a formal resemblance to a life table, but, from the nature of the case, it can have little or no bearing upon the course of events in a normal community. Naturally, however, one desired to set up some normal standard of mortality for the animal species used and, having obtained some scanty data, one was led to speculate further upon the biology of the so-called “laws” which have been from time to time proposed to describe the course of mortality in man. In this paper, I have brought together the imperfect results of such study as I have been able to make. Their practical value, from the point of view of the description of human mortality, is, it need hardly be said, negligible, while as a contribution to the history of “laws” of mortality what is omitted is perhaps as important as what is discussed. I have, however, felt justified in printing this essay in the hope that it might be accepted as a tribute in piam memoriam of my friend and colleague John Brownlee. The title of one of Brownlee's papers—“The Biology of a Life Table”—was the inspiration of much of his life-work. He approached the problem with an erudition, both biological and mathematical, to which I have no pretensions and, had his power of exposition been equal to his natural sagacity and learning, there would have been small need of any other writer. [ABSTRACT FROM PUBLISHER]

In a recent series of papers, Flexner (1922), Lynch (1922), Amoss (1922a and b) and Webster (1922a and b) record the results obtained at the Rockefeller Institute in an experimental investigation of epidemics among laboratory animals. These experiments bear a close similarity to those which have been recorded in previous papers of the present series (Topley, 1919, 1921 a and b, 1922 a and b, and Topley, Weir and Wilson, 1921). Their publication affords an opportunity of comparing the results obtained in two independent enquiries, which have been carried out along slightly different lines, and of describing in more detail certain points in the general technique of our own experiments, which have an important bearing on the significance of the results obtained. [ABSTRACT FROM PUBLISHER]

In the present paper we describe the results of further investigations on the life-history of Piroplasma canis in the blood of the dog. In our last paper (x. 1906) we described and figured the movements of the parasite and the mode of multiplication in the dog's blood, and since that time we have confirmed most of our previous observations, and added further facts. The technique of these examinations was fully explained in that paper (p. 604), and it is only necessary to state here that all our later observations on living blood have been made at a temperature of 35°—40°C. The drops of blood were mounted on clean glass slides and cover-glasses kept at this temperature, and were placed as rapidly as possible on the stage of a microscope kept at a similar temperature in a Nuttall's thermostat and examined under a oil immersion lens. In fact we have endeavoured to make our observations in such a manner that the blood should be altered as little as possible. [ABSTRACT FROM PUBLISHER]

On reading the excellent paper on the parasites of the Culicidae recently published by Dr Léon Dyé, I was struck by the fact that several of the organisms mentioned by him had been seen and described by me long ago in the course of my original studies on malaria and mosquitoes carried out in India during 1895–1899. My observations were, however, recorded for the most part in Indian medical publications, which are little accessible to European readers, and have been so far forgotten that some of the parasites of mosquitoes seen by me have been recently rediscovered by various observers. It may therefore be of interest—perhaps not alone from the historical point of view—to resuscitate these old records and compare them with more recent and exact work. I may add that attempts were made by me to infect men with two of the organisms which I observed. My writings on the subject were contained in the following publications, which are here numbered for reference:— [ABSTRACT FROM PUBLISHER]

The following is an addendum to a paper which appeared in the last number of this Journal.The primary object of the paper was to give working formulae for the construction of a shortened Life-Table, set forth with sufficient clearness to enable them to be practically used by anyone who understands ordinary arithmetic and the use of logarithms, without any necessary comprehension of the principles of the differential or of the integral calculus, by means of which the formulae have been deduced. [ABSTRACT FROM PUBLISHER]

1. The ordinary method of calculating the birth-rate does not distinguish between the influence of fertility and of variations in conditions of the population as to age and marriage.2. In ascertaining the true meaning of the great reduction of the birth-rate which has occured in the last 25 years it is necessary to have means for distinguishing between the accidental and the intrinsic causes of change.3. A step in the right direction is made when the legitimate births are stated in terms of the married women at child-bearing ages, and the illegitimate births in terms of the unmarried women of the same ages.4. This method fails to correct for the differences of fertility of the various ages comprised in the age-period 15–45.5. By calculating standard fertility-rates for given populations McLean overcame the above difficulty, and was thus able to compare experiences of a given community at different times with the standard.6. In this paper it is shown that by continuing the above process and obtaining corrected fertility-rates, the fertility-rates of different communities can be made directly comparable.7. The inconveniences of this new and unfamiliar method, and the necessity involved in it of calculating the crude as well as the corrected fertility-rate in every instance, indicate the desirability of obtaining a factor for each community which throughout an entire intercensal period can be applied to the crude birth-rate of that community.8. The desirability of such a factor is increased by the fact that the method of corrected fertility-rates does not take into account the proportion of married women in each population.9. In this paper a method is described of obtaining factors, which, when applied to the readily available crude birth-rates, correct completely both for the varying proportion of married women in compared populations and for the varying fertility at different periods of married life.10. The practical bearings of these corrected birth-rates will be discussed in a later paper. [ABSTRACT FROM PUBLISHER]

The following notes are to serve as a postscript to the paper which appeared under the above title in the preceding number of the Journal of Hygiene (pages 1—42). [ABSTRACT FROM PUBLISHER]

Ninety-nine young Gambian children were studied for 61 weeks. About half of them had trachoma at the outset, and 80 % of the remainder acquired the disease while under observation. IgG trachoma antibody in the serum and IgG and IgA antibodies in the conjunctival secretions (CS) were titrated by an indirect immunofluorescence method. In serum samples obtained in capillary tubes the mean titre was slightly higher than in samples collected on filter paper. Sorum antibody at titres ↛ 1/10 was invariably associated with a clinical diagnosis of trachoma; it increased both in frequency and titre as the disease progressed, and was present in about half of those with Tr II. In CS, IgG antibody was present less often and at lower titres than in serum, and IgA antibody was detected even less frequently. There was some evidence of correlation between the titres of IgG and IgA antibodies in CS, but none for a relationship between the titres of the antibodies in serum and those in CS. Antibodies were almost never present in the absence of conjunctival follicles, but their titres were unrelated to the degree of follicular hyperplasia; there was no obvious relationship between the serological findings and corneal lesions. In children diagnosed clinically as trachoma, serum antibody was present in almost all those with conjunctival inclusions, and in a proportion of inclusion-negative subjects; the mean titre was much higher in the inclusion-positive group.These findings do not settle whether CS antibodies are made locally, or are derived partly or wholly from the blood. They suggest that the indirect immunofluorescence test may be a useful diagnostic aid in trachoma, particularly in view of the rarity of false positive reactions; but there is at present little to choose between it and complement-fixation tests in terms of sensitivity. [ABSTRACT FROM PUBLISHER]

This paper describes a search for Gram-negative bacteria in an operating theatre and the steps taken to reduce the level of environmental contamination.A high rate of infection in clean wounds prompted a bacteriological survey. Potential sources of infection found, and the measures employed are described in the hope that others may be encouraged to examine familiar equipment critically and to improve hygiene even in old premises.The choice, design, use and care of cleaning and sterilizing equipment were open to criticism. In particular, a currently popular floor-scrubbing machine provided a breeding ground for Pseudomonas aeruginosa and was distributing it in the theatre environment. [ABSTRACT FROM PUBLISHER]

Reasons for the accumulation of mercury-resistant strains of Staphylococcus aureus in hospital have been studied. A collection of paired strains, that is staphylococci similar in every respect except sensitivity to mercury salts, was made. Tests were made in an attempt to demonstrate a link between mercury resistance and some other factor which might aid survival, viz. resistance to drying and heat, production of bound coagulase, growth in the presence of sublethal amounts of tetracycline, survival in human blood at 37°C. and uptake by polymorphs at 30°0. and 37°C., development of resistance to antibiotics and competition in mixed cultures. It was not possible to demonstrate any consistent link between mercury resistance and any of these properties. Paper strips impregnated with the mercurial diuretic, Mersalyl, were shown to differentiate between mercury-resistant and -sensitive strains in vitro. Furthermore, development of resistance to mercury by passage in mercuric chloride-broth was demonstrated.It is proposed that mercury resistance has developed as a result of exposure to the mercury ion. Mercurial diuretics have been frequently used in medical and geriatric patients and it is among these that the higher carrier rates of mercury-resistant strains are found even when the local endemic strain is disregarded. In obstetric patients, where mercurials are seldom used, mercury-resistant strains are rare.Nasal carriage of factory workers exposed to mercury products showed that this group is likely to carry resistant or partially resistant strains. [ABSTRACT FROM PUBLISHER]

In view of recent food-borne outbreaks of salmonella infection in which cooked-meat slicing machines have been implicated in the spread of organisms from contaminated meat products to other meats, experiments have been made to provide laboratory evidence that a contaminated slicing machine will easily cross-contaminate other products passing through it. Chopped pork inoculated with coagulase-positive staphylococci was cut on a slicing machine; staphylococci were isolated up to the 41st slice of various cooked meats cut on the same machine. The experiments were repeated with Salmonella oranienburg; this serotype was isolated up to the 31st slice of various cooked meats cut on the same machine, and from pieces of damp cloth wiped over the gravity feed, knife centre disk and cutting blade.The importance of efficient and regular cleaning of slicing machines with hot water containing detergent/disinfectant, or detergent followed by disinfectant, applied with clean cloths or preferably disposable paper, is stressed.I thank Dr Betty C. Hobbs, Director of the Food Hygiene Laboratory, and Dr J. C. Kelsey, Administrative Director of the Central Public Health Laboratory, for their help throughout the work and the compilation of the paper. [ABSTRACT FROM PUBLISHER]

Plaque neutralization on HEp 2 cells was used to determine the relationship between vaccinia, rabbitpox, cowpox and ectromelia using both 7 S and 19 S antibody. It was shown that for the strains of virus used vaccinia and rabbitpox were very similar but cowpox and particularly ectromelia were clearly distinguishable. The cross-titration relationships were the same for 7 S and 19 S antibody.The titration slopes and kinetics of cross-neutralizations were interpreted on the basis of a hypothesis of antibody competition put forward in the preceding paper. It was tentatively concluded that these four viruses share a common critical antigen for neutralization and that differences in the structure or presentation of neighbouring antigens could give rise to some of the observed effects. [ABSTRACT FROM PUBLISHER]

1. Irradiation in a whole body dose of 200 rads or more increased the sensitivity of mice to intraperitoneal infection with Langat virus so that the LD 50 was increased to about the intracerebral LD 50.2. In mice given 500 rads before infection: (a) viraemia was prolonged by about 5 days; (b) the IgM response was depressed; (c) the IgG response was delayed by about 3 days and depressed in titre; (d) virus concentration in the brain rose continuously until death on about the tenth day while in the controls it reached a peak on the fifth day then subsided; (e) histological changes in the CNS were delayed and minimal even at death; (f) irradiated mice died with little evidence of paralysis while the controls died with severe paralysis.3. In irradiated mice, protection was observed when antibody was administered on the third day following infection. Antibody given on the 3 days after infection to control mice aggravated the disease.4. The results in this and the preceding paper are discussed in relation to the pathogenesis of encephalitis. It is concluded that neuronal damage is caused both by virus multiplication in neurones and by damage superimposed by inflammatory changes with associated oedema and hypoxia. The inflammatory changes appear to be due to an allergic reaction to virus-antibody complexes formed in the circulation and in the central nervous system.We are grateful to Miss S. J. Illavia, B.Sc., and Miss G. E. Fairbairn for their skilled technical assistance; to the Department of Radiotherapy at St Thomas's Hospital for providing time and staff to help with the irradiation experiments; and to Mr S. Peto of the Microbiological Research Establishment for statistical advice.This work was made possible by a generous grant from the Wellcome Trust and the Endowment Funds of St Thomas's Hospital. [ABSTRACT FROM PUBLISHER]

This paper elaborates a concept of enrichment dynamics introduced in an earlier paper in which the author set out to find a labour saving technique for isolating salmonellac from sources other than faeces. Extensions to the concept are summarised in the Introduction. Explanations are given why a multiplicity of isolation procedures used in combination should normally yield more isolations than any one procedure alone.Since a limit must always be set on the number of different media and procedures which can be used during routine examinations, a corresponding limit has also to be set on the combined efficiency of the procedures used. Not even a very laborious combination of methods can be expected to yield quite 100% of the isolations that are technically possible. When this rather unpalatable conclusion is accepted, a way is opened up for compromises between endeavour and reward, in terms of salmonella isolations. Judicious application of principles and methods discussed in these papers might be expected sometimes to lead to modifications in techniques which increase their efficiency, and in other cases to modifications which reduce labour without diminishing efficiency. [ABSTRACT FROM PUBLISHER]

A simple device by which the characters of an unknown organism can be com pared with those of named genera and species is described. The comparison is made by using ‘diagnostic tables’ of characters found to have differential value.Separate tables for Gram-positive and Gram-negative bacteria were made; the first stage indicated the probable genus into which the unknown fell and a second (and occasionally a third) stage was needed to identify the species or subspecies.We wish to thank Dr Ruth E. Gordon for much unpublished data which were invaluable in constructing Table 1 gg, Miss Helen E. Ross for helping with Table 1f, Dr Oleg Lysenko for letting us use data from a paper about to be published, and Mr W. Clifford for the photographs and figures. [ABSTRACT FROM PUBLISHER]

Part I1. The following disinfectants were investigated for use in bar-soaps: Hexachlorophene (G11) (2:2′-dihydroxy-3:5:6:3′5′:6:′-hexachlorodiphenylmethane); Actamer (2:2′-thiobis, 4-6-dichlorophenol); DCMX (dichloro-m-xylenol); TMTD (3:4:5-tetramethyl thiuram disulphide); TCC (3:4:4′-trichlorcarbanilide); TBS (3:4′:5-tribromsalicylanilide) and TCS (3:3′:4′:5-tetrachlorsalicylanilide).2. The concentration required for bacteriostasis of Staph. aureus was 2·5 p.p.m. for DCMX and 0·1 p.p.m. for TCS, the other disinfectants falling between these values. None were effective against E. coli, 12·5–50 p.p.m. being required for bacteriostasis (Tabel 1).3. In the presence of serum the concentration required for bacteriostasis was increased (Table 4).4. The soap inactivation coefficient (S.I.C.) is a value derived from zone diffusion tests. Zone diameters of the same disinfectant are compared in soap and soap-free solution so that the S.I.C. measures the effect of soap on disinfectant activity.5. DCMX is inactivated by soap (S.I.C. = ∞). The activity of G 11 is much reduced by soap (S.I.C. = 200). Actamer and TMTD are active in soap, whereas TCC, TBS and particularly TCS is more active in soap than soap-free solution (S.I.C. = 0·32) (Table 3).6. Another test based on zone diffusion is described which measures the effect of soap-soluble skin substances on disinfectant activity. Zone diameters of the same disinfectant are compared in fresh soap and used soap solutions.7. Of the disinfectants tested only TMTD lost some of its activity in the presence of soap-soluble skin substances (Table 5).Part II8. Conventional bacteriological plate-counting technique was used to enumerate bacteria in wash-water. The bacteria were removed from hands by using a standardized washing procedure with bar-soap but without scrubbing.9. Bacteria were not removed uniformly when washing was carried out twelve times in succession, significantly more bacteria being removed at the beginning of of the washing procedure.10. When the same individuals were tested at weekly intervals the rate at which bacteria were removed in successive washes was found to vary significantly.11. Using a single standardized wash the variation in the count of twenty individuals was followed for a period of 16 months. The count from one individual could vary by a factor of 10.12. A design for a handwashing test, to take account of these variables is described. The bacterial counts of the wash-water when subjects used control soap for 1 week was compared with counts obtained from subjects using disinfectant soap. Subjects and soaps were randomized according to multiple Latin squares.13. This handwashing technique was used to test the disinfectants described in Part I of this paper. All these disinfectants were effective but tetrachlorsalycilanilide (TCS) was the best. Soap containing 0·5% TCS caused an 84% reduction (Table 9).The authors wish to thank Dr H. Wilkinson for the ideas he contributed and the interest he has shown in this work, and the Directors of Unilever Limited for permission to publish this paper. [ABSTRACT FROM PUBLISHER]

Field observations on myxomatosis in wild rabbit populations of the Riverine Plain of south-eastern Australia, extending between August 1951 and March 1953, were reported. General observations on vector abundance and disease incidence were made over a large area. Detailed analysis of the population counts, age structure and immune status of the rabbit population, and the occurrence of insect vectors, were made at one site, Lake Urana.The case-mortality rate in the first epizootic was in the neighbourhood of 99·8%, whereas in the second epizootic it was about 90 %, and many more chronically sick rabbits were observed in the later outbreaks. The virulence of eight strains of virus recovered from mosquitoes at Lake Urana in December 1952 and four strains recovered at Corowa at the same time was found to be somewhat reduced when they were compared with the original standard laboratory strain of virus. It is thought that this attenuation is the major reason for the observed change in the case-mortality rates.The mosquitoes, Anopheles annulipes and Culex annulirostris were by far the most important insect vectors of myxomatosis in this region.Thanks are due to Messrs F. N. Ratcliffe, B. V. Fennessy, and H. J. Frith of the Wildlife Survey Section of C.S.I.R.O. for helpful discussion and assistance during the field work and in the preparation of the paper. The technical assistance in the field of Messrs C. S. Hale and K. L. S. Harley is gratefully acknowledged, as is the generous help afforded by the landholders of Lake Urana, especially Mr J. Muldoon, and by Mr W. Quirk, rabbit inspector. [ABSTRACT FROM PUBLISHER]

Factors affecting the formation and destruction of sulphide in the Thames Estuary have been discussed. Measurements of oxidation-reduction potentials show that the effect of oxygen in the water on conditions in deposits of mud is limited to the surface layer. The rate of formation of sulphide increases with temperature, doubling approximately for each 10° C. rise. Reduction of sulphate to sulphide will occur at temperatures as low as 5° C., but even at 25° C. is inhibited by traces of dissolved oxygen. Mud in suspension in the estuary can produce as much sulphide as compact layers of similar mud which might be more anaerobic.Oxidation of sulphide in the Thames Estuary is shown to be of a purely chemical nature; the rate of oxidation, when oxygen is present, is increased by the presence of suspended matter and iron. In the Thames Estuary, however, the rate is limited by the rate at which oxygen enters the water.Much of the experimental work described in this paper was carried out by Miss A. Laird, Mr A. E. Sutton and Mr R. B. Peel of this Laboratory. The paper is published by permission of the Department of Scientific and Industrial Research. [ABSTRACT FROM PUBLISHER]

The complement-fixation technique described in this paper was designed as a simple and rapid micro-method. It is derived from the method published by Fulton & Dumbell (1949), but a number of modifications have rendered it less laborious to perform and more flexible in application. Using rabbit, human and guinea-pig antisera, this technique has been successfully applied to the serological examination of the viruses of influenza, vaccinia and Newcastle disease, and experience with other materials, such as gonococcal antigen and extracts of chorio-allantoic membrane and mouse lung, suggests that it is of general application. [ABSTRACT FROM PUBLISHER]

1. Four different Bacteriaceae possessing the same Vi antigen showed, after exposure to heat, striking differences in the physico-chemical behaviour of the Vi antigen. The most noticeable differences observed were those in the changes in Vi-agglutinability and O-inagglutinability of the bacteria; lesser differences were noted in the agglutinogenic activity of the Vi antigen, and none in its agglutinin-binding capacity.2. Treatment with alcohol altered the TVi antigen of one of the species (Bact. coli 5396/38) in a way different from that seen in the other three species.3. On the other hand, dilute acid or alkali produced the same chemical changes in the TVi antigen of all four Bacteriaceae.4. The TVi antigen present in the four Bacteriaceae appears to be one and the same substance; it cannot be differentiated by the customary serological methods. Its different physico-chemical state after exposure to heat or alcohol is, therefore, conditioned by other constituents of the bacterial cell, which may, or may not, be antigenic.5. The simultaneous O- and Vi-inagglutinability resulting from heating at 75° C. is particularly impressive since it does not appear to be specially related to any one of the known antigenic components.6. These findings invalidate the basis on which the L, A and B antigens of Bact. coli have been differentiated.7. There is also no valid reason for designating the labile somatic antigens of Salmonella and other Bacteriaceae as K antigens. These antigens have the general characters of the Vi antigen of Salm. typhi, are demonstrated by methods developed in the study of the typhoid Vi antigen, and are not associated with typical capsules.8. The M (mucoid) antigens of Salmonella and of Bact. coli are in many respects different from the Vi antigens and should be classified separately.I gratefully acknowledge the valuable technical assistance received from Mr F. J. Flynn throughout the work reported in this and the preceding papers of this series. [ABSTRACT FROM PUBLISHER]

The Cambridge University Health Service started work in October 1948. So far it has been restricted to preventive measures and has been confined to new entrants to the University on an entirely voluntary basis. The Service provides a clinical examination and a chest X-ray. A general survey of the scope of the Service and the results obtained have been given in the annual reports of the Senior Health Service Officer, Sir Alan Rook (1950, 1951). In addition to the original clinical records a Hollerith punched-card record system has been used since the inception of the Service to facilitate detailed investigations. In Appendix I to the first annual report mentioned above (Rook, 1950) I gave a few preliminary results on various physical measurements for the first 900 men examined. It has now been possible to complete a much more extensive investigation, the results of which are given in the present paper. In some cases this has been based on the completed records for the year 1948–9, while in others the records for the two years 1948–50 have been utilized. I have already given a brief summary of the contents of this paper in Appendix I to the second annual report (Rook, 1951). [ABSTRACT FROM PUBLISHER]

When individual responses in a biological assay show considerable variation associated with the values of a concomitant variate, covariance analysis may be used in order to adjust the mean responses and to improve the precision of the assay. Usually this is preferable to the choice of an adjustment which involves an arbitrary assumption about the effect of variations in the concomitant variate on the measured response. Published accounts of the process are open to certain theoretical objections, though they may be sufficiently exact for most practical purposes.The present paper describes a method of calculating the relative potency, and its precision, which may be a little more laborious, but which is in full accord with standard statistical practice. The computations are illustrated on data from a prolactin assay by the pigeon crop-gland technique, in which the final crop-gland weight showed a positive correlation with the body weight at the start of the assay. The results are compared with those obtained either from the unadjusted crop-gland weights or from these weights expressed as proportions of body weights. The covariance method leads to a more precise estimate of the potency of the test preparation than do either of the others; there is evidence, however, that the increase in precision will not necessarily be large unless the correlation between the response and the concomitant variate is very close.In a final section, the full statistical tests of assay validity in the covariance analysis are described; these are lengthy, and fortunately are required only when the validity is in considerable doubt.The methods of adjustment have been described in this paper with respect to an assay depending upon parallel regression lines of responses on the logarithms of doses. They may be adapted for use with ‘slope-ratio’ assays (Bliss, 1946; Finney, 1945; 1948; Wood & Finney, 1946), in which the regression of response on dose itself is linear. So far the need for adjusting for concomitant variation in these assays seems not to have arisen, and discussion of computational details may be postponed until the need is felt. [ABSTRACT FROM PUBLISHER]

Growth of bacteria in an infusion of flax under quiescent conditions resulted in the formation of an acidic liquor with an appreciable content of volatile acids. When a similar infusion was aerated by a continuous current of air, the liquid tended to become alkaline and the content of volatile acids was much smaller and in some cases negligible. Aeration reduced the polluting strength of the liquor, as measured by oxygen absorbed from permanganate and by the biochemical oxygen demand, by much larger amounts than did growth under quiescent conditions.Experiments with infusion in which the natural flora was allowed to grow, and with sterile infusion inoculated with pure strains of different types of bacteria, showed that the general effect of aeration was to alter the metabolism of the bacteria in the direction of more complete oxidation of the substrate. Balance sheets for carbon showed that the organic carbon lost from the culture was accounted for by the CO2 evolved. Thus carbohydrates, which under anaerobic conditions were fermented to organic acids, neutral volatile compounds, and gases, were oxidized, when the conditions were sufficiently aerobic; to CO2 and water.The magnitude of the effects observed depended largely on the nature of the organisms present, and partly on the strength of the infusion in which they grew. With pure cultures of Bact. coli, Bact. aerogenes and Bacillus subtilis, and with the natural mixed flora of the flax, aeration at moderate rates in bottles for 3–5 days reduced the value for oxygen absorbed from permanganate by 43–52 %, and the biochemical oxygen demand by 26–92 %, indifferent experiments. The organic carbon content of the infusion was reduced by 30–31 % by Bact. aerogenes, by Bacillus subtilis and by the mixed flora. With streptococci and with a strain of Achromobacterium the effects observed were very small. Aeration at higher rates with diffused air in small open tanks reduced the organic carbon content of a flax infusion by 50 % in about 80 hr., and of a beetroot infusion by 50 % in about 60 hr. Sugar was destroyed during the aeration and disappeared rapidly from the flax infusion in the early stages.The work described in this paper was carried out in connexion with an investigation of retting of flax and disposal of waste waters, made, as an extramural research, for the Ministry of Supply as part of the programme of the Water Pollution Research Board of the Department of Scientific and Industrial Research. The paper is published by permission of the Chief Scientific Officer, Ministry of Supply, and of the Department. [ABSTRACT FROM PUBLISHER]

This paper embodies the findings in all proven cases of diphtheria admitted to the Hull City Hospital during the years 1938–43 inclusive. All cases during those 6 years were typed and the clinical and bacteriological findings correlated. Since 1932 all severe cases had been typed and in the winter of 1932–3 a consecutive series of 313 cases was investigated and the results published (Leete, McLeod & Morrison, 1933). The 1933 paper showed a high gravis incidence of 59% and an associated high case fatality rate. Not until the end of 1937 was it again possible to type every case admitted but since then we have done so, and the series now presented embodies observations on 2039 infections, the great majority of which were clinical cases. [ABSTRACT FROM PUBLISHER]

1. In the course of this investigation we have dealt with many cases of refection, but during a period of several years we never obtained the condition except when raw potato starch was the carbohydrate in the synthetic diet. Recently, in the exceptional circumstances described in the text, we have had a few cases with rice starch.2. Like other authors, we have always found that in refected rats the caeca are always enlarged and their contents the seat of specially great bacterial activity. The nature of the dominant organisms present has varied from case to case, and in one it was apparently a yeast. Nevertheless, there is a suggestion that certain organisms are more potent in promoting refection than others. In rice starch refection, such organisms seem to be present.3. We have found that the administration of roughage in the manner described can, to a large extent, prevent the establishment of refection. The number of organisms in the caeca is then greatly reduced and the contents indeed may become nearly sterile.4. Using potato starch as the carbohydrate of the diet, we have had no difficulty in reproducing the results of the early experiments published by one of us (Hopkins, 1912), but we found that to obtain a growth induced by administering very small quantities of milk to vitamin-free diets, the presence of this starch is necessary. Indeed, the growth so promoted calls for the same particularity in the carbohydrate supply as does the establishment of refection.5. Nevertheless, we have obtained what seems to be conclusive evidence showing that the growth with milk is wholly independent of refection.6. We have obtained some evidence that potato starch contains growth factors in association with protein which only becomes soluble when liberated by treatment with pepsin HCl. As our experimental results bearing on this, for some reason at present unexplained, have lacked constancy, we can only claim, that they are suggestive. [ABSTRACT FROM PUBLISHER]

1. A study has been made of different types of coliform bacteria with particular reference to (a) their ability to ferment lactose in MacConkey broth at different temperatures, and (b) the effect of using different temperatures of incubation for the indol, methyl-red, V.P., and citrate tests.2. It was found that 97% of the cultures of Bact. coli (indol positive, methyl-red positive, V.P. negative, citrate negative) examined could ferment lactose with production of acid and gas between 40 and 44° C. The number was not appreciably reduced at 45° C. but was markedly reduced at 46° C. 28% of the cultures of Bact. coli (indol negative, methyl-red positive, V.P. negative, citrate negative) and 15% of Bact. aerogenes (indol negative, methyl-red negative, V.P. positive, citrate positive) were found to be positive at 44° C.3. The adoption of a temperature of incubation of 30°C. for the V.P. test as advocated by Levine (1941) and the use of O'Meara's test showed that many cultures previously regarded as unable to produce acetylmethylcarbinol were in fact able to do so. Employing a temperature of 30°C. for 5, or in some cases 7, days for the methyl-red test, it was found that with nearly all the cultures tested there was an inverse correlation between the results of the methyl-red test and those of the V.P. test. With these modifications in technique some cultures originally designated as Intermediate type I were found to have reactions corresponding with those of Bact. aerogenes type I. Similarly, many cultures originally classified as Intermediate type II should have been typed as Bact. aerogenes type II.4. It was found that all cultures of Intermediate type I classified as such by the new technique were incapable of using the nitrogen of uric acid for growth, but that the majority produced hydrogen sulphide. Cultures of Bact. aerogenes type II, on the other hand, grew well in uric acid medium, but produced no hydrogen sulphide.The investigation described in this paper was carried out by the Freshwater Biological Association, as part of the programme of the Water Pollution Research Board of the Department of Scientific and Industrial Research. The paper is published by permission of the Department. [ABSTRACT FROM PUBLISHER]

It has long been recognized that there is a relationship between environment and health and examples of this association are easy to cite—overcrowding tends to spread infection. But our knowledge of the exact part played by occupational as distinct from economic and social environment is as yet imperfect.' The liability of the worker to ill-health, apart from any inborn constitutional weakness, is determined broadly by two factors. The first is the influence of the type of work directly upon the worker, an influence inherent in the actual occupation and the conditions under which the work is done. This might be regarded as the direct occupational risk. The second is the economic and social environment conditioned by the occupation followed: this might be termed the indirect occupational risk. This distinction was recognized by the Eegistrar-General who stated that both factors are essentially components of the total occupational risk since ' If a man is obliged by his place of work and his rate of pay to live in an insanitary area, the extra risk of death involved is, in a wider but very real sense, part of the occupational risk'. The purpose of the present paper is to try to disentangle the parts played by each in determining the occupational mortality from a specific disease like tuberculosis. The difficulty which previously presented itself was the absence of a standard which could be regarded as a measurement of the indirect occupational risks. The Registrar-General, in his last Occupational Mortality Supple-ment, has provided an approximate index, by publishing data on the mortality of males following particular occupations and also that of their wives. His viewpoint was.'. for no trade could longer be regarded as directly prejudicial to health if it were found to entail as much excess risk for the wife as for the husband. In such a case excess mortality would evidently be in the main attributable to the social conditions implied.' Greenwood likewise stated that ‘the wives share the social and geographical advantages of their husbands’ occupation but, with relatively ummportant exceptions, are not exposed to their specific occupational risks’. The purpose of the present paper is to try to disentangle the parts played by each in determining the occupational mortality from a specific disease like tuberculosis. The difficulty which previously presented itself was the absence of a standard which could be regarded as a measurement of the indirect occupational risks. The Registrar-General, in his last Occupational Mortality Supplement, has provided an approximate index, by publishing data on the mortality of males following particular occupations and also that of their wives. His viewpoint was. ‘..for no trade could longer be regarded as directly prejudicial to health if it were found to entail as much excess risk for the wife as for the husband. In such a case excess mortality would evidently be in the main attributable to the social conditions implied.’ Greenwood likewise stated that ‘the wives share the social and geographical advantages of their husbands’ occupation but, with relatively ummportant exceptions, are not exposed to their specific occupational risks'. [ABSTRACT FROM PUBLISHER]