bluuebunny/crossref_metadata_2025_split huggingface dataset:
The spermicidal powers of chemical contraceptives VII. Approved tests
Authors: Baker John R. , Ranson R. M. , Tynen J. 
Published: May 2009

1. All tests of spermicidal power are done with human semen at 37° C.2. The total spermicidal power of pure substances and commercial products is measured by a test which is not intended to represent natural conditions very closely, but which gives consistently reliable results. The activity of the sperms is determined at 5 and at 30 min.3. A commercial product of high total spermicidal power may be useless on account of the slow rate of diffusion of the spermicide out of the vehicle. A special test measures the rate of diffusion. This test is designed to represent natural conditions as well as is possible in the laboratory. The test is made as stringent as possible by avoiding mechanical mixture of the product with the semen. The activity of the sperms is determined at 2, 5, 15, 30, 60, 120, and 180 min.4. The rate of disintegration and acidity or alkalinity of commercial products is measured.5. The pathological test consists in inserting one-half the prescribed dose of a commercial product into the vagina of a bitch daily (except Sundays) for a fortnight, and then sectioning the vagina and examining microscopically.6. A method is described whereby the pH of human semen may be determined colorimetrically rather accurately.7. The average ejaculate of the human semen we have studied, from 13 donors, measures 3·9 c.c, contains 461 million sperms, and requires 3·1 c.c. of N/100 HCl to neutralize it.
Notes on the Subject Matter of a Previous Paper
Authors: Buchanan-Wollaston H. J. 
Published: May 2009

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.
The Lipoid Antigens of C. Diphtheriae and C. Hofmannii
Authors: Hoyle L. 
Published: May 2009

1. Antisera prepared by immunizing rabbits with C. diphtheriae gravis, mitis, and intermedius and C. hofmannii contain antibodies which will give complement-fixation reactions with alcoholic extracts of the organisms.2. By means of cross-absorption experiments three different lipoid antigens can be demonstrated: (a) a specific antigen h present only in C. hofmannii; (b) a specific antigen d characteristic of C. diphtheriae mitis but probably present also in small amount in C. diphtheriae gravis and intermedius; and (c) a non-specific or group antigen G present in large amount in C. diphtheriae gravis and intermedius and C. hofmannii, and in small amount in C. diphtheriae mitis; this G antigen is probably made up of a number of components.3. Sera of human diphtheria convalescents may contain antibodies reacting with alcoholic extracts of C. diphtheriae. Sera from mitis cases usually react only with extracts of G. diphtheriae mitis, i.e. they contain only d antibody, while sera from gravis or intermedius cases usually contain only G antibody and react with extracts of C. diphtheriae gravis, intermedius and C. hofmannii, but not with extracts of G. diphtheriae mitis.
Bacteriological observations on the air of occupied premises: I. air disinfection with hypochlorites. a simple practical method of disinfecting the air of occupied premises
Authors: Challinor S. W. 
Published: May 2009

Substantial reduction in the bacterial content of the air of an empty room after infection with B. prodigiosus (or with Staphylococcus albus or a diphtheroid bacillus) has been effected by means of hypochlorites introduced into the air by atomization from a Dynalysor or by spraying from a flit gun.The ‘normal’ variation of the bacterial content of the air of an occupied (crowded) room has been described.Repeated spraying of a solution containing 1% of sodium hypochlorite or of a 1·3% suspension of water-sterilizing powder (bleaching powder) from a flit gun has been shown to reduce materially the bacterial content of the air of the occupied room.Similar sprayings of water have been shown to have no appreciable effect on the bacterial content of the air of the occupied room and the action of the hypochlorite was, therefore, not merely a mechanical removal of bacteria from the air.Methods have been devised for assessing the degree of disinfection per individual spraying of hypochlorite, and, although the methods are mainly of comparative value, it may be stated that the reduction in the total bacterial content of the air of the occupied room for a single spraying of hypochlorite Y (≡1% sodium hypochlorite) was of the order of 33%, or more. The percentage reduction of potentially pathogenic bacteria which may have been present was almost certainly greater than the reduction of the total bacterial content, which included resistant saprophytic bacteria. The average concentration of hypochlorite Y used in these experiments was 0·38 c.c. per million c.c. of air (i.e. less than 11·0 c.c. per 1000 cu. ft. of air) per spraying, i.e. was exceedingly small, and even smaller concentrations were equally effective when the hypochlorite was atomized into the air by means of the Dynalysor.Rather less consistent results were obtained with the chemically less active bleaching powder suspension than with hypochlorite Y in the flit-gun experiments.The relative humidity of the air has been shown to be a factor of great importance, and in the experiments described in this paper effective air disinfection was not obtained at low relative humidities at temperatures ranging from 54 to 74° F. The need for accurate determination of the critical lower limit of relative humidity is stressed.Tobacco smoke has been shown to reduce the efficiency of hypochlorite sprays but the experimental evidence was insufficient for any definite conclusion to be drawn.The advantages and disadvantages of hypochlorites as air disinfectants have been discussed and the conclusion reached that repeated (every 20 or 30 min.) spraying of the air of an occupied room with a 1% solution of hypochlorite (e.g. hypochlorite Y) constitutes a simple, practical, inexpensive and efficient method of air disinfection, and, provided simple precautions are observed, there are no serious objections to such a procedure.
The effect of temperature of incubation on the results of tests for differentiating species of coliform bacteria
Authors: Taylor C. B. 
Published: May 2009

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 ofBact. 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 ofBact. coli(indol negative, methyl-red positive, V.P. negative, citrate negative) and 15% ofBact. 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 ofBact. aerogenestype I. Similarly, many cultures originally classified as Intermediate type II should have been typed asBact. aerogenestype 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 ofBact. aerogenestype 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.
Further work on forecasting smallpox epidemics in India and British tropical countries based on previous climatic data
Authors: Rogers Leonard 
Published: May 2009

1. Earlier work on forecasting epidemics of smallpox in India, based on the study of the previous rainfall and humidity, has been confirmed and extended by the present study and a few instances which did not conform to the general rule have been explained as due to the spread of the disease from an adjacent province.2. An extension of the inquiry to other tropical countries of the British Empire indicates that in tropical countries in general with well-marked dry and wet seasons, the annual decline of smallpox incidence to a low minimum in relation to high absolute humidities during the rainy season is the rule; for it is absent in equatorial Uganda with rains throughout the year, and both the monsoon period and the monthly incidence of smallpox are reversed in such a Southern Hemisphere country as Nyassaland in accordance with the general rule.3. Where smallpox is endemic in such countries increased prevalence in any year may usually be foreseen by watching the meteorological records in time to control the expected increase to some extent by increased use of vaccination.4. Other air-borne diseases are worthy of study on similar lines in countries with suitable vital statistics and climatic conditions.
Nuclear reorganization in non-sporing bacteria
Authors: Bisset K. A. 
Published: May 2009

1. The process of nuclear fusion and reorganization as it occurs in members of the Bacteriaceae is described.2. The chromosomes behave as pairs at all times, the normal bacillus, of smooth morphology, contains two pairs.3. The fusion nucleus contains three pairs and is preceded by a corresponding trinucleate bacillus.4. One division of the chromosomes takes place in the fusion nucleus, and another during the process of redistribution of the chromosomes. The second division is followed by fragmentation, and return to the bacillary condition.
The counting of surface colonies of bacteria
Authors: Crone P. B. 
Published: May 2009

A colony count performed by spreading a known volume of suspension on the surface of a plate possesses certain advantages over other methods, of which the chief is ease of counting.The distribution of counts of several samples of the same suspension on medium of the same age and batch is as expected on statistical grounds.Different batches and ages of blood plates may give substantially the same count but this is not true for Leifson's and Wilson & Blair's media.A diluting fluid, which is satisfactory if blood agar is the plating medium, may not necessarily be so if special media are to be used.
The conglutination phenomenon IX. The production of immuno-conglutinin in rabbits
Authors: Coombs A. M. , Coombs R. R. A. 
Published: May 2009

1. An investigation has been carried out into the conditions necessary for the production of immuno-conglutinin in rabbits.2. The inoculation of complement adsorbed on sensitized cells stimulates the production of immuno-conglutinin. We have called this procedure hetero-stimulation.3. Immuno-conglutinin also results from the inoculation of untreated but killed bacteria. This procedure for its production we call auto-stimulation. Gram-negative bacteria appear to be more effective stimulants than Gram-positive bacteria. Soluble antigens did not appear to be as effective as bacterial suspensions.4. The necessity for clarifying the part played by immuno-conglutinin in in vivo immune processes has been stressed.The authors would like to thank the following for gifts of experimental materials: Mr H. I. Field, strains of S. pullorum; Dr J. Boissard, strain of C. hofmanni; Dr C. H. Lea and Dr R. S. Hannan, purified casein; Miss Dunkerley, Bence Jones protein. Cx polysaccharide for testing acute phase protein in rabbit serum was made available by the kindness of Dr McCarty of the Hospital of the Rockefeller Institute for Medical Research, New York; and much of the work on this aspect was done in consultation with Dr H. C. Anderson, to whom we are most grateful.
The use of influenza virus labelled with radio-sulpher in studies of the early stages of the interaction of virus with the host cell
Authors: Hoyle L. , Finter N. B. 
Published: May 2009

1. Influenza virus can be labelled with 35S by cultivation in fertile eggs into which radioactive methionine has been introduced.2. When virus labelled with 35S is fractionated by ether treatment the nucleoprotein soluble antigen fraction contains 15 % of the 35S, the haemagglutinin also contains 15%, while the denatured envelope protein contains 70% of the 35S.3. When sulphur-labelled virus is introduced as a primary inoculum in fertile eggs and extracts of the chorioallantoic membrane are made 1–20 % of 35S is recovered as amino-acid, while the remainder is present as non-infective material of particle size similar to that of the original virus.4. It is suggested that on entry into the cell the virus nucleoprotein is hydrolysed with the release of amino-acid and free nucleic acid, while the virus envelope protein and haemagglutinin remain on the cell surface.The authors are indebted to the Medical Research Council for a grant in aid of expenses, and to Messrs. Eli Lilly and Co. for the generous provision of the Spinco centrifuge used in this work. The radioactive methionine was obtained from the Radiochemical centre at Amersham.
The Use of Tests on Slaughterhouse Cattle for Estimating Relative Potencies of Tuberculins and for the Calculation of Discrimination Tests
Authors: Paterson A. B. , Stuart P. , Lesslie I. W. , Leech F. B. 
Published: May 2009

1. The potency of PPD tuberculin made from AN 5, a bovine strain, was high when WR medium was used and low when BAI medium was used. PPD tuberculin made from strains of the human type grown on BAI medium was intermediate in potency between the two bovine PPDs.2. The standard deviation of the difference between responses to duplicate injections of human type PPD at 2·0 mg./ml. concentration was 2·59 in the Islington and 1·84 in the Weybridge experiment on tuberculous animals, and 1·11 at Islington and 1·13 at Weybridge on tubercle-free animals. Differences greater than 1·5 mm. were relatively infrequent on tubercle-free animals.3. The Elliott ‘401’ electronic computer at Rothamsted was used to calculate discriminant functions and to estimate the discriminating power of different ‘tests’, each test involving an injection of a mammalian and an injection of avian tuberculin.4. There were some differences between the mammalian preparations in their power to discriminate between tuberculous and tubercle-free animals, but these differences were closely allied to differences in potency. It seems probable that if concentrations of equivalent potency were used, there would be little if any difference in their discriminating power.5. The contribution of avian tuberculin to the discrimination test was demonstrated; the greatest contribution came from a concentration of 0·25 mg./ml. used in the Islington experiment. The Weybridge results were quite consistent with the assumption that a maximum contribution is made by a concentration less than 0·5 mg./ml.6. Methods for deducing rules for the interpretation of comparative tuberculin tests, using a mammalian and an avian tuberculin are illustrated and results given for the type of population sampled in these experiments.7. The principle on which this rule might be modified where the population is believed to be free of infection, is outlined and discussed.We should like to acknowledge the advice and constructive criticisms during the planning of the experiments of Dr A. W. Stableforth and Dr H. H. Green of Weybridge, and also the care with which Miss C. N. Hebert carried out the preliminary arrangement of the large quantity of data. Thanks are also due to the staff of the Islington abattoir for their willing co-operation.
The sources of Hospital infection of wounds with Clostridium welchii
Authors: Lowbury E. J. L. , Lilly H. A. 
Published: May 2009

The air of operating theatres ventilated by powerful extractor fans was sampled during operations with special media for Cl. welchii and Staph. aureus, and also for total organisms. Counts made with the slit-sampler showed the presence of Cl. welchii in all samples in a range slightly higher than that of Staph. aureus (mostly between five and twenty-five colonies per 100 cu.ft.). There was no evidence of a build-up of either Cl. welchii or Staph. aureus during the course of operations, nor were there any consistent peaks of contamination during operations.Settle plates exposed on numerous days in the operating theatres showed similar counts of Cl. welchii and Staph. aureus—the latter slightly more abundant in this series. Settle-plate counts from many parts of the hospital and from the road outside provided evidence that airborne Cl. welchii comes into the hospital from outside, while Staph. aureus is contributed to the air inside the hospital. This view was supported by study with the slit-sampler and with settle plates in a dressing station ventilated with filtered air, where Cl. welchii was rarely found and Staph. aureus momentarily abundant during dressings; staphylococci but not Cl. welchii were dispersed by the operators in a mock operation. The numbers of airborne Cl. welchii inside and outside the hospital were higher in dry than in rainy weather.Of the patients in the Burns Unit 35% had at some stage Cl. welchii in their burns; contamination was commoner in the more extensive burns. In contrast to Staph. aureus, Cl. welchii was usually present in small numbers and for a short period.Cl. welchii was found in the burns of twenty out of thirty (66%) patients whose rectal swab taken on admission showed the presence of Cl. welchii; a significantly smaller proportion of patients whose rectal swabs were free from Cl. welchii picked up the organism while in hospital (eight out of thirty-two, 25%; x2 = 9.4, P < 0.01). This observation supports the view that burns and possibly other wounds acquire Cl. welchii by self-infection at least as often as from the environment. While it is obvious that plenum ventilation of operating theatres with filtered air is desirable, it is uncertain to what extent this will reduce the small hazard of post-operative gas gangrene.We wish to thank Miss G. Hogg and Mr L. Hurst, F.I.M.L.T. for technical assistance, the surgeons and nursing staff of the Birmingham Accident Hospital for their co-operation, Mr N. R. Gill for photography, and Professors A. A. Miles and C. L. Oakley for kindly sending us strains of Cl. welchii.
Tetanus antitoxin titration by haemagglutination at a low level of test
Authors: Fulthorpe A. J. 
Published: May 2009

An investigation has been made of methods of estimating the antitoxin content of small samples of human sera by haemagglutination procedures.The direct agglutination test appears to be satisfactory when dealing with groups of sera, but was unreliable for testing individual sera.The discrepancies observed in the direct agglutination test were greatly reduced by adopting an agglutination inhibition test at the LA/100 level of test.The difference in agglutinating capacity of both avid and non-avid sera perin vivounit of antitoxin did not appear to be related to avidity.
Rinderpest Immunity in Calves: I. The Acquisition and Persistence of Maternally Derived Antibody
Authors: Brown R. D. 
Published: May 2009

Rinderpest neutralizing antibody was found to be transferred from the immune dam to the calf via the colostrum. No antibodies were detected in the sera of calves before suckling. The colostrum of immune cows contained rinderpest antibodies to a higher titre than that of the serum; 30–48 hr. after the ingestion of such colostra, newborn calves possessed high antibody levels in their sera, levels greater than those of their dams' sera but less than those of the colostrum ingested.After the neonatal period the serum titres of calves declined linearly. The mean half-life of maternally derived rinderpest antibody in calves was 36.7 days and the extinction point 10.9 months.Two young calves, from susceptible dams, which each ingested daily for 5 weeks 1 gallon of milk containing rinderpest antibodies failed to show evidence of their absorption from the intestinal tract.
An electron microscope study of molluscum contagiosum
Authors: Charles Arwyn 
Published: May 2009

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.