bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quaternary ammonium compounds. A new technique for the study of their bactericidal action and the results obtained with cetavlon (Cetyltrimethylammonium bromide)
Authors: Davies G. E. 
Published: May 2009

1. Some sources of error in the testing of quaternary ammonium compounds for bactericidal activity have been investigated. These resolve themselves into (a) errors caused by bacteriostasis, and (b) errors caused by the clumping of bacteria.2. A suitable technique, free from these errors, is described.3. Cetavlon in 0·1% solution is a powerful bactericide even in the presence of moderate amounts of organic matter.4. One per cent Cetavlon will not kill spores at room temperature even when contact is maintained for several days.5. Bacteria surviving the action of quaternary ammonium compounds retain their virulence.
Some observations on the reaction between horse serum and a pool of rabbit antihorse serum. II. An analysis of the antigens concerned in the production of multiple zones
Authors: Naylor G. R. E. 
Published: May 2009

1. The reaction horse serum and a pool of rabbit antihorse serum exhibiting four α procedure optima has been investigated with a view to analysing the antigens involved in the production of the multiple zones.2. The following conclusions have been reached regarding the antigenic constitution of horse serum, a horse serum-albumin preparation and a horse serum-globulin preparation: Horse serum consists of at least five antigens. The horse serum-albumin preparation contains three antigens, two of which are probably impurities, one of these being a globulin. The horse serum-globulin preparation consists of three antigens and evidence was obtained of a fourth. Electrophoretic analysis of these protein preparations gave concordant result.3. Multiple zones of rapid particulation in the precipitation reaction are due to the independent activity of multiple antigens and their homologous antibodies.4. The absorption of precipitin from a mixture of antibodies by a mixture of antigens at a single α procedure optimum is both a useful and a practicable procedures.5. Attention is drawn to the fact that the method of antigenic analysis used in the present series of experiments, involving the correlation of α; procedure optima occurring in the parallel titrations of a single antiserum against a mixed antigen and equivalent concentrations of physically or chemically prepared fractions of it supplemented by absorption of precipitins at individual and multiple α precedure optima and retitration of the absorbed sera, could be applied to the identification and nomenclature of proteins occurring in natural mixtures, and also to the quantitative and qualitative appraisal of the purity of proteins prepared by physical or chemical means. The method does not rely on the preparation of highly purified protein samples containing a single antigen.
The morphology of the genusLeptospiraas shown by the electron microscope
Authors: Babudieri B. 
Published: May 2009

Several species ofLeptospirahave been studied by means of the electron microscope. Their morphology is described. TheLeptospiraconsists in a long homogeneous cylinder of protoplasm, enveloped in a very thin anistic membrane and wrapped around a slender axistyle. Vibratile structures and granules generally are lacking.The appearance of Leptospiras differs according to different methods of fixation used and according todifferent physical or chemical treatmentsto which they are subjected.
The carcinogenic activity of some petroleum fractions and extracts. Comparative results in tests on mice repeated after an interval of eighteen months
Authors: Woodhouse D. L. , Irwin J. O. 
Published: May 2009

Woodhouse's experiments on the carcinogenicity of ten different fractions for the skin of mice have been analysed statistically. Two experiments separated by a considerable period of time were performed on each fraction.A number of different measures of carcinogenicity were used. All agree in showing that(1) The apparent carcinogenicity was greater in the 2nd series of experiments.(2) There were significant differences in carcinogenicity. The fractions can be divided into three groups within which the carcinogenicities were about the same, viz. F H I K, B D G L E, M.
The theory of amoebic surveys
Authors: Lancaster H. O. 
Published: May 2009

(i) The theory of amoebic surveys and of related types of pathological surveys is discussed.(ii) An inequality is derived,whereXis the total number of carriers andX1,X2are the new carriers found at the first and second examinations.(iii) Demonstrability is defined and several theoretical distributions of it are considered.(iv) Demonstrability is shown not to be a constant in the populations considered.(v) The danger of extrapolation is noted.(vi) Life-table methods are introduced to treat some well-known published series.(vii) A criterion for the adequacy of any estimate of the total carrier rate is given. The mean demonstrability of the outstanding carriers after successive examinations must form a decreasing series.(viii) This criterion usually shows that the method of estimating the carrier rate forEntamoeba histolyticaas three times the proportion of positives at a single examination, or as the total number of positives picked up in six examinations, both give too low a carrier rate.(ix) It is suggested that the investigation of the ‘carrier’ rate may in certain cases be merely a measure of ‘demonstrability’.(x) Possible future lines of investigation of the problem are noted.
Statistical control in haematology
Authors: Lancaster H. O. 
Published: May 2009

The value of ‘Statistical control’ in haematology has been demonstrated. After a short historical survey of the chief contributions to the theory of the technique of counting and of the application of the Poisson distribution in biology, the statistical theory of the distribution of cells in the haemocytometer is briefly described and examples are given of large sample methods of testing goodness of fit. Some of the author's counts are considered.In the red cell counts a ‘crowding’ effect is noted by which the variance between the counts on the individual squares on the haemocytometer is reduced. This effect is trivial in white cell counting owing to the small proportion of the area occupied, but is important in reducing the variance between the numbers of red cells on individual small haemocytometer squares. A quadratic function adequately describes the regression of the variance on the mean for fixed size of haemocytometer square, for the usual range of red cell density. This function, calculated on the basis of the author's own counts also describes Berkson's findings on crowding adequately and is not, considering the approximations involved, inconsistent with the theoretical discussion on crowding. Reasons are given for believing that the crowding effect is only trivial if blocks of 16 squares are compared in red cell counting.The methods of statistical control, suggested by R. A. Fisher's work, are introduced. It is shown that they give satisfactory results when applied to some of the author's own counts. The methods are used to discuss the consistency of the counts of certain medical graduates and technicians. The methods are suitable for a review of the literature with the object of examining the internal consistency of the counts made by various authors.
The standardization of staphylococcal α-antitoxin, with special reference to anomalous haemolysins including δ-lysin
Authors: Marks J. 
Published: May 2009

1. Evidence is submitted that an anomalous rabbit cell lysin reported by Minett (1936), α2-toxin and δ-haemolysin are identical. The last name is preferred.2. Precautions are necessary to avoid interference by δ-haemolysin in titrations of α-toxin and α-antitoxin.3. The existence of γ-haemolysin is confirmed; its wide distribution and possible confusion with α-toxin are noted. The name γ-toxin is thought more suitable than γ-hameolysin.4. Multiple standard antisera are desirable for the detection of anomalous toxins. At least one should be of refined globulin.5. Dilution and manipulation inactivate staphylococcal toxins and their effect needs consideiration in quantitative work. Infusion broth increases the stability of diluted α- and β-toxins.
Experiments on the food preferences of wild rats (Rattus norvegicusBerkenhout)
Authors: Barnett S. A. , Spencer Mary M. 
Published: May 2009

1. Colonies of wildRattus norvegicusBerkenhout were kept in closed rooms containing nesting sites. The conditions permitted breeding.2. Seventy-six experiments, each lasting 6–35 days, were done to test the rats' food preferences. In each experiment except two, a choice was given between two foods, both available in excess. In the two exceptional experiments a choice between three foods was given.3. Although marked preferences were shown, a food was rarely quite rejected in favour of an alternative.4. Among cereals, wholemeal was preferred to wheat grains, but wheat grains were preferred to white flour; little or no white flour was eaten if wholemeal was available. Wheat germ was eaten only in small quantities when an alternative cereal was available, but in larger quantities if the alternative was sugar or a sugar-cereal mixture.5. The addition of sugar or saccharin to cereals increased acceptability; sugar was preferred to saccharin.6. The addition of arachis oil to wholemeal or wheat increased acceptability.7. Cod-liver oil at 2·4 % acted as a deterrent.8. Total calorific intake remained steady over short periods, but over several weeks rose as the mass of the rat colony increased. The higher the mean weight of the rats in a colony, the lower the calorific intake per unit weight of rat.9. The amount of food eaten was partly determined by its calorigenic capacity: in particular, wet foods were eaten in much larger quantities than dry foods.10. The food preferences of wild rats differ in several respects from those of whiteRattus norvegicus.11. Apart from palatability or flavour, the main factors influencing food preference were (a) previous experience and probably (b) the nutritional value of the food. The effect of previous experience was often observed when rats, accustomed to one food, gradually changed from the accustomed food to another. The stages of a change to a new food, or the establishment of a particular preference, varied, and are discussed in detail.
Immunity of Guinea-pigs to Diphtheria Toxin and its Effect upon the Offspring
Authors: Südmersen H. J. , Glenny A. T. 
Published: May 2009

1. Diphtheria toxin-antitoxin mixtures induce a higher immunity in guinea-pigs than sub-lethal doses of toxin; one injection of the mixture being sufficient to produce an immunity lasting in some cases for a period of over two years, as shown by the passive immunity conferred on the offspring.2. The highest immunity is produced by toxin-antitoxin mixtures containing the most uncombined toxoid.3. The active immunity of the mother is transferred passively to the offspring.4. The passive immunity thus transferred usually disappears at the end of two months after birth, and only in rare instances has been recongnised after three months.5. Immunity is mainly transmitted in utero, and only to a slight extent during lactation.6. Young bred from does that have been used for a single routine antitoxin test may be able to tolerate 14 times the does of diphtheria toxin fatal for a normal guinea-pig.
Purification of Water by Infusoria
Authors: Stokvis C. S. , Swellengrebel N. H. 
Published: May 2009

Infusoria have the same bactericidal power as flagellates. Emulsions containing Bacillus typhosus, Vibrio cholerae, V. Dunbar, V. El Tor, B. megatherium and Spirillum volutans, to which Colpoda cucullus is added, are soon cleared. Before the clearage the Colpodae multiply actively.This bactericidal effect does not depend upon the production of toxic substances by the Infusoria. The fluid obtained from filtered cultures of the Infusoria exerts no bactericidal effect. Only living Colpodae are able to clear the emulsions.Direct sunlight does not prevent the clearing of the emulsions by the Infusoria, but temperatures below 10°C. and above 30°C. and absence of oxygen (anaerobic culture) are unfavourable to their exerting a bactericidal effect.The polluted water of the canals of Amsterdam slightly delayed the clearage of the emulsions; the sewage of starch factories and gas factories completely prevented this clearage.Consequently under natural conditions Infusoria will only play a part in purifying river water (1) if the temperature is above 10° and under 30°C., (2) if the aquatic vegetation is rich enough to supply the necessary quantity of oxygen, (3) if the water is not highly polluted by adjoining factories.
The Effects of Dosage in Typhoid Vaccination of Rabbits
Authors: Smith J. Henderson , Brooks Ralph St John 
Published: May 2009

Following the subcutaneous injection of typhoid vaccine into rabbits the average antibody response was estimated from day to day, and found to vary for agglutination, bactericidal action, phagocytosis (including tropins), “precipitation” and probably for complement-fixation according to the dose of vaccine.As estimated by the maximal value reached by the serum the response increases with increasing dose in nearly all cases. This increase becomes relatively less and less as the dose increases, and its progress suggests that with a sufficiently large dose a limiting-value might be reached, which if not actually a true limit would be practically one.The observed relationship between dose and effect is such as to suggest that the combination of antigen and reacting-cell takes place in accordance with the rules governing adsorption processes; but this does not hold for the response in bactericidal power.With increasing vaccine-dose the date at which the maximal value is reached gets later for the various antibodies, with again exception of the bactericidal power.The precipitation observed differs from the usual precipitation reaction and is perhaps really an agglutination-phenomenon.Phagocytosis was observed in three ways, and the bearing of the results on the mechanism of the action of the antibody concerned is considered; and the relationship between the bactericidal and other antibodies is also discussed.
Further Observations on the Occurrence of Iodine in Relation to Endemic Goitre in New Zealand and on Iodine Metabolism
Authors: Hercus C. E. , Aitken H. A. A. , Thomson H. M. S. , Cox G. H. 
Published: May 2009

1. Most artificial manures are found to have some effect in increasing the iodine content of crops, particularly superphosphate.2. Marked differences are found between the iodine contents of Samoan and New Zealand foodstuffs corresponding to the non-goitrous condition of Samoa and the partial endemicity of New Zealand.3. Investigation of the dietaries of fifteen residential institutions showed that improvement in provision of iodine was necessary in many cases by using fish at least twice a week, raising the daily ration of milk to 1 pint per head, and employing iodised salt for table and culinary purposes.4. Dietetic experiments indicate (i) that on a change of diet adjustment of iodine metabolism may take a considerable time, (ii) that iodised salt is most effective in promoting storage of iodine when associated with a meat diet.5. Iodine excretion is found to decrease much more rapidly under fasting than on a diet very low in iodine.6. Iodised salt has the effect of adjusting the excretion of goitrous adults to the normal non-goitrous value.7. The iodine content of the blood is found to be lower than normal in cases of simple colloid and simple nodular goitre, though it may range from low to abnormally high in cases of Graves' disease. In all types of goitre the thyroid gland is low in iodine.8. The ratio of thyroid iodine to total bodily iodine is about 12 per cent. in the case of the white rat under ordinary conditions, but the ratio is found to vary considerably with the iodine intake.9. Great differences in the ratio of the weight of the thyroid gland to that of the whole body are found among different species of animals, the ratio being higher for the dog than for the monkey.10. Variations in commercial samples of iodised salts are recorded and discussed.11. Data are given in regard to the iodine and chlorine content of rainwater in different localities.
Prophylactic Vaccination in Epidemic Meningococcal Meningitis
Authors: Riding D. , Corkill N. L. 
Published: May 2009

1. An epidemic of meningococcal meningitis, due to Type II meningococcus, occurring in a large native population is briefly described.2. A method of preparing prophylactic meningococcal vaccine on a large scale, and its experimental application in the epidemic is demonstrated.3. The results obtained in two similar groups of natives, one inoculated with meningococcal vaccine and the other with T.A.B. vaccine, as to the incidence of, and death rate from, meningococcal meningitis are detailed.
Combining Affinities in Bacterial Variation and Carcinogenesis
Authors: Eastwood Arthur 
Published: May 2009

Although knowledge of principles determining variation is imperfect, some progress has been made and further help may be obtained from some of the newer conceptions about combining affinities regulating normal growth. There are reasons to believe that growth depends on a rhythmic cycle of synthesis, peculiar to living protein, whereby at each successive stage one particular “building stone” is selected for synthesis, with rejection of all others. There is also some evidence that the surface of a growing bacterium passes through periodic phases. Additional light on the activities of the bacterial surface is thrown by the new conception of enzymes which regards them not as fixed chemical entities but as chemico-physical “centres of activity.”Some of the principles which are gradually coming to light in bacterial variation may ultimately be of assistance in the much more obscure problem of explaining the change from the normal mammalian cell to its malignant variant. I refer in particular to conceptions, which I have discussed in the preceding part of this article, about the mechanism of cellular growth and the nature of a cell's combining affinities.
Granular “O” Agglutination in Paratyphoid B and Typhoid Fevers
Authors: Gardner A. D. , Stubington Edith F. 
Published: May 2009

The granular “O” agglutination of human serums from eighty cases of typhoid and paratyphoid B fevers has been titrated with carefully selected killed typhoid “O” and paratyphoid B “O” suspensions of high sensitiveness.In spite of a wide overlapping, due to common factors, a considerable specificity is shown, and this can be utilised in differential diagnosis, especially if due attention is paid to the different levels of “normal” agglutination for the two species.
Cancer Susceptibility in Relation to Colour of Mice
Authors: Twort C. C. , Twort J. M. 
Published: May 2009

An examination of some 10,000 tumour-bearing mice appertaining to 240 experiments comprising 24,000 animals has been made to find whether there was any difference in sensitiveness of the skin to our carcinogenic agents, according to colour of coat and eyes. Methods involving only elementary arithmetic have been utilised as we have, unfortunately, no statistical mind on our staff, and thus we have, presumably, failed to derive full benefit from the data available. We have ventured, however, to draw the following tentative conclusions as regards the particular animals under discussion, they being obtained from varied sources:1. Self-coloured animals (excluding pure white) were more sensitive to petroleum oils (weak agents) than the corresponding piebald. (That is, a black was more sensitive than a black and white, etc.)2. When tars (strong agents) were utilised instead of petroleum oils an opposite state of affairs existed, the self-coloured animal being more resistant than its piebald companion. This reversal may be explained on the grounds of cell tolerance.3. Pink-eyed animals (excluding pure white) had a greater all-over sensitiveness of the skin to our agents than pigmented-eye animals.4. On the whole the most sensitive animal was the pink-eyed fawn.5. The frequency of hyaline degeneration of the spleen and marked thyroid enlargement was greater among pink-eyed animals, especially when fawn coloured, than among pigmented-eye animals.
The Bacterial Purification of Gasworks' Liquors. The Action of the Liquors on the Bacterial Flora of Sewage
Authors: Happold Frank Charles , Key Arthur 
Published: May 2009

A study has been made of the bacterial flora in the sewage supplied to, and the effluent from, the bacteria beds which deal with the liquors produced at the Coventry gasworks. A high count in the effluent from the beds of bacteria containing an oxidase system, or a relatively large increase in the viability of such organisms when compared with the original sewage, has been found to be concurrent with good purification in the beds, and vice versa.The bacterial flora undergoes considerable modification in the beds, and also when mixed with 4 per cent, of its volume of spent liquor in the laboratory. The total viable count of the treated sewage is reduced under these conditions, but the count of those bacteria which give the direct oxidase reaction and therefore catalyse the oxidation of catechol is relatively increased.A gram negative vibrio (strain 0 1) is the only bacterium isolated which has proved capable of breaking down monohydric phenols. It has been constantly isolated from the effluent liquors.Gasworks' ammonia liquor in the relatively high concentrations used exerts a markedly toxic action on all types of sewage bacteria, and the purification of this liquor by the beds is not so satisfactory. The toxicity is probably caused by the highly alkaline reaction of the liquor.This investigation was commenced by one of us (F. C. H.) in conjunction with Dr Allan C. Monkhouse, who was at the time Research Chemist to the Liquor Effluents Sub-Committee of the Institution of Gas Engineers. Dr Monkhouse accepted another appointment shortly after the commencement of the work, and was therefore unable to assist further, but we should like to express our indebtedness to him during the initial period. We are also indebted to Prof. J. W. McLeod and Prof. J. W. Cobb for their kindly interest and encouragement, and to Mr P. N. Langford, Engineer and Manager of the Coventry Gas Department, for the facilities he so generously placed at our disposal at Coventry.One of us (F. C. H.)is in receipt of grants from the Medical Research Council, and would again express his thanks to that body.One of us (A. K.) is indebted to the Liquor Effluents and Ammonia Sub-Committee of the Institution of Gas Engineers for permission to publish this work.