bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations on the Meningococcus Carrier-Rate in relation to density of population in Sleeping Quarters
Authors: Glover J. A. 
Published: May 2009

1. A high meningococcus carrier-rate in a military unit denotes that dangerous overcrowding exists in this unit.2. Severe overcrowding (i.e. when beds are less than 1 foot apart) is usually accompanied by a carrier-rate (serological) of at least 20 per cent.(Twenty per cent. is the danger line indicated in the War Office Memorandum on Cerebro-spinal Fever, March 1917.)3. A carrier-rate of this height will usually imply that the mobilization standard of 40 square feet has been infringed, and also that beds are less than 1 foot apart.4. A carrier-rate of 20 per cent. (without awaiting the occurrence of any actual cases of the disease) should be regarded as a signal for prompt and effective action to abolish overcrowding, and to improve ventilation, and to increase the distance between the beds to at least 2½ feet.5. The distance between beds is of paramount importance.6. Carrier-rates of between 10 and 20 per cent. are unsatisfactory and imply a certain degree of overcrowding. They must be watched with suspicion, and the mobilization standard strictly enforced.7. Under the same conditions of overcrowding “non-contact” carrier-rates are the same as “contact” carrier-rates.8. Quite a moderate degree of “spacing out” of beds, combined with simple methods for improving ventilation are highly efficient agents in reducing high carrier-rates.9. When, however, a unit shows a high carrier-rate, insistence on the restoration of the mobilization standard is not sufficient.“Spacing out” must be carried further; and a distance of at least 2½ feet between beds insisted on.The “peace” standard of 3 feet between beds and 60 square feet of floor space with 600 cubic feet of air space would, of course, be still more effective.10. The mobilization standard, introduced for a grave emergency, is the lowest possible concession to military necessity, which can be allowed with safety.
Studies of Selective Bactericidal Action
Authors: Cooper E. Ashley , Mason John 
Published: May 2009

1. The three organisms B. pyocyaneus, B. fluorescens-liquefaciens and non-liquefaciens form a closely related group of organisms both biologically and also by reason of their behaviour towards disinfectants.2. Bacteriological observations support the view that germicides can naturally be divided into two classes, viz. “chemical” and “physico-chemical,” their actions on micro-organisms depending respectively on(1) Chemical reactivity with protoplasmic constituents.(2) Denaturation or precipitation of the cell proteins.3. B. fluorescens non-liquefaciens and related organisms are selectively attacked by “physico-chemical” germicides, e.g. phenol, whilst B. coli is less sensitive to their action, but is particularly susceptible to the “chemical” disinfectants, e.g. quinones.The B. fluor. non-liq. group is also more readily affected by hot water than B. coli.4. Substitution of various groups into the benzene nucleus in the case of aromatic disinfectants affects the germicidal power on B. coli and B. fluor. non-liq. unequally, with the result that the selective action and differentiation may be obscured or even reversed in the case of the substituted derivatives.5. B. fluor. non-liq. is more sensitive than B. coli to the action of reducing agents, and this factor also affects the degree and nature of selective action, sometimes resulting in the classification of “chemical” germicides in the “physico-chemical” group.6. Selective action is not affected by changes in experimental conditions, such as temperature and period of disinfection, nature of culture medium, number of bacteria present, or physical state of the disinfectant. The susceptibility of B. fluor. non-liq. to the action of hot water, and such germicides as phenol and alcohol, is thus probably associated in some way with its internal colloid state.7. The analogy between the action of hot water and that of the alcohols and phenols is borne out by preliminary experiments with the thermophile bacteria (heat resistant). These organisms are somewhat less sensitive to phenol that B. coli, and more susceptible to p-nitrosodimethylaniline.
A Statistical Analysis of Age Distribution of Asthmatics
Authors: Harvey W. F. , Kermack W. O. , Lyon D. M. , McKendrick A. G. 
Published: May 2009

A statistical analysis has been made of the figures collected during the last eight years in the Edinburgh area, relating to asthmatic patients who presented themselves for examination in certain departments of the Edinburgh Royal Infirmary. The figures for males and females are considered separately, and refer to the numbers of individuals who presented themselves at various, ages, and in whom the disease first manifested itself at various earlier ages. In all, complete records were obtained of 193 males and 167 females. For convenience the ages are grouped in five-year periods.It has been shown that the figures in the case of females agree well with the assumption that asthmatics, no matter at what age they are first affected, gradually cease to suffer from the disease, or at least fail to report for examination, at a rate which is constant and independent of age. In the case of males the agreement between theory and observation is not as good as in the case of the females, but much of the discrepancy results from two or three obviously aberrant figures. Of every 100 asthmatics at any age it would appear that approximately 7 females, or 8 males as the case may be, are transferred to a non-complaining category every year. The absence of complaint may be due to death from asthma, or recovery, or to some other cause, as for example, that by repeated experience the individual learns how to avoid conditions which precipitate an attack.On this assumption the relative rates of incidence (P) of the disease at various ages have been calculated for males and for females. Both curves fall during adolescence, rise to a maximum, and then gradually fall, but the male curve lags behind the female curve. From these figures the rates of attack amongst the potential asthmatics (p) have been calculated both for males and for females. The curves fall during adolescence, then rise, remaining practically constant until about 45 years of age, when a rise occurs towards unity. For the further analysis of these curves larger numbers of figures will be necessary, in order that confidence may be placed in the results.
The Spermicidal Powers of Chemical Contraceptives: II. Pure Substances
Authors: Baker John R. 
Published: May 2009

1. A technique for comparing the spermicidal powers of pure substances is described in detail. It is hoped that this may be accepted as the standard technique for the purpose.2. The killing concentration of each substance is determined by this technique. The killing concentration is defined as the lowest concentration, in the series 2, 1, ½, ¼ per cent., etc., which suffices to kill every guinea-pig sperm suspended in glucose-saline solution in half an hour at the temperature of the body in four consecutive experiments, the majority of the control sperms being moderately or very active.3. 36 substances have been graded by this technique.4. Mercuric chloride and formaldehyde were found to be the most spermicidal substances. The killing concentration of each per cent.5. Hexyl resorcin kills at per cent., soaps at per cent.6. Formaldehyde and hexyl resorcin, among other substances, seem likely to be useful as contraceptives.7. The significance of the high spermicidal power of soaps is discussed.8. Quinine bisulphate and chinosol, which are perhaps more commonly used as contraceptives than any other substances, only kill at ½ per cent.9. Certain very poisonous substances have very slight spermicidal powers. This applies to potassium cyanide, prussic acid and strychnine hydrochloride.10. Foaming mixtures, consisting of acids and sodium bicarbonate, could probably be used alone as contraceptives.11. The acrosome is the part of the sperm most vulnerable to spermicides. It tends to swell up and burst.12. Sperms are very susceptible to changes in osmotic pressure.13. It is the hydrogen ions and not the anions of acids that kill sperms.14. The suggestion that tribasic acids would be found to be more spermicidal than dibasic, and dibasic than monobasic, is not substantiated.15. Substances which reduce surface tension are often effective spermicides.16. The characters of the ideal chemical contraceptive are discussed.17. The need for co-operation in research in chemical contraception is stressed.
Milk epidemic of angina, originating from a Cow with mastitis and due to Streptococcus pyogenes (Lancefield group A)
Authors: Henningsen E. Juel , Ernst J. 
Published: May 2009

A report is given of a milk epidemic of septic sore throat, comprising about 100 cases.The epidemic originated from a cow with a slight degree of mastitis, produced by a Streptococcus pyogenes (Lancefield's group A).The same Streptococcus (which we did not succeed in typing) was isolated from 74% of the patients examined and from three persons who were handling the milk.It seems reasonable to assume that the cow was infected from the milkers. Owing to particular conditions in the distribution of the raw milk, it is possible that the milk delivered raw in the village involved on one day a massive contamination.The epidemic is characterized as moderately severe. No case terminated fatally.
Studies on the type division of the typhoid and paratyphoid B bacilli by fermentation
Authors: Kristensen Martin 
Published: May 2009

No case of transformation (in vivo) of the “xylose-positive” typhoid bacillus to the “xylose-negative”, or vice versa, has been observed in any of the material dealt with at the State Serum Institute, Copenhagen.On the other hand, the types of paratyphoid B bacilli that can be established on the basis of their relation to rhamnose and inositol did not prove to be absolutely constant; actual or apparent transformation of one type to the other having been observed in several cases.In this connexion the suggestion is made that Bitter's rhamnose reaction be omitted; the distinction between types R1 and R2 would thus disappear.Patients with symptoms of diseases of the liver and biliary system and also chronic carriers were represented in greater numbers for type R3I1 than for type R2I1, but it is doubtful whether this observation can be taken as a general one. Apart from this, the behaviour of these two types was very uniform as to the clinical course of the infections they produced. The cases of infection with the rarer types, also, did not seem to vary clinically from those with the more frequent types. On the other hand, the difference between the clinical course of paratyphoid B and the infection with Salmonella typhi murium was very marked.
The Eijkman test for faecal coli in the bacteriological examination of water supplies
Authors: Batty-Smith C. G. 
Published: May 2009

1. A historical survey is given of work upon the Eijkman method.2. A total of 104 water samples were examined by methods I and III. These yielded 602 cultures obtained from the 44 and 37° C. presumptive series, and of these 357 were 44° C.-positive. The only types capable of fermenting lactose at 44° C. wereBact. colitype I and Irregular type II, with the addition of three cultures of intermediate type I and two ofaerogenestype I.3. The relative efficiencies in the detection ofBact. coliof the 44° C. method by direct inoculation and of the 37° C. presumptive test with plating and differentiation were compared. Out of 104 samples, sixty-eight were shown to contain faecalBact. coli, and in 19% of these the 44° C. method detectedBact. coliwhen it was not recovered at 37° C. The converse was true in only 13% of samples.4. The results obtained by other workers in regard to the specificity of incubation at 44° C. and to the various methods hitherto proposed for employing it have been collected and discussed; technical advantages and disadvantages have also been considered.5. It is concluded: (1) That false positives at 44° C. are a negligible quantity for practical purposes. (2) That the best all-round method to use is Wilson's method IV. (3) That 48 hr. incubation should be given, but that 24 hr. is sufficient when rapidity is desired. (4) That the test should be officially recognized and standards laid down for use with it.6. Cellobiose was found to be inferior to citrate for the identification of the I.A.C. group.
The serological grouping ofStreptococcus lactis(group N) and its relationship toStreptococcus faecalis
Authors: Shattock P. M. F. , Mattick A. T. R. 
Published: May 2009

1. It has been shown on serological and biochemical grounds thatStr. faecalisfalls into Lancefield's group D.Str. liquefaciensis considered to be a variety ofStr. faecalis, andStr. glycerinaceus(Orla Jensen) has insufficient claim to a separate name.2.Str. lactishas, on biochemical and serological grounds, been clearly differentiated fromStr. faecalisand the other members of group D.3. Reasons are given for assigningStr. lactisto a new serological group ‘N’ into whichStr. cremorisalso falls.
The bacteriology of activated sludge
Authors: Allen L. A. 
Published: May 2009

Homogenization of activated sludge greatly increased the apparent bacterial count obtained by plating on a solid medium, and for this reason facilitated the isolation of the predominant flora by liberating the bacteria from the interior of the sludge flocs. The ordinary domestic cream-making machine was found to be quite effective for this purpose.The high counts obtained indicated that there are probably several hundred thousand million bacteria per gram of dry matter in activated sludge.Aeration of sewage was found to result in an increase in the total count of bacteria, and a high count was maintained for a considerable time. After aeration for several days fairly rapid and apparently fairly complete separation of the sludge occurred on allowing the liquid to stand, but the supernatant liquor contained large numbers of bacteria. When a fresh quantity of sewage was added to the small quantity of sludge which settled and a second period of aeration commenced, the bacteria were found to associate more quickly with the sludge than they had during the first aeration. Coliform bacteria and spore-forming aerobes formed only a small fraction of the total number of micro-organisms concerned in these changes, and moulds and yeasts never accounted for a large proportion. The predominant bacteria did not produce acid from glucose.Various media were tested in investigating the bacteriology of activated sludge. None showed any superiority to nutrient agar. Coliform bacteria and aerobic spore-formers were encountered in negligible numbers. The morphological and physiological characters of seventy-one strains of the predominant bacteria were determined. The majority were Gram-negative rods with no action on carbohydrates and were members of the generaAchromobacterium, Chromobacterium,andPseudomonas.Those isolated from activated sludge soon after its formation from aerated sewage were found to be non-proteolytic, but a proteolytic flora was established after the sludge had been built up for a period of 4 weeks. The characters of the predominant bacteria indicate that they are water types derived from the water supply or the drainage water which enters sewage. Intestinal bacteria appear to be unimportant.The experiments described in this paper were carried out as part of the programme of the Water Pollution Research Board of the Department of Scientific and Industrial Research, and the results are published by permission of the Department.
Mode of origin of sulphonamide-resistant strains inB. dysenteriaeFlexner
Authors: Stewart F. H. 
Published: May 2009

The change by which a strain ofB. dysenteriaeFlexner becomes resistant to sulphonamides is similar in character to the change inB. coli mutabilefrom white (non-lactose-fermenting) to red (lactosefermenting).The highest proportion of variants are found in papillae, while no variants are found in the growing margin of colonies.Reversion does not take place during growth on sulphonamide-free media.The variation is a direct and heritable response to a chemical stimulus and in adaptation to this part of the environment.The variation described by Reiner Müller ofB. typhosuson rhamnose and of certain coliform bacteria on arabinose may also be of the same nature.Strains ofB. dysenteriaeFlexner resistant to sulphanilamide or sulphaguanidine 1/10,000 are only partially resistant to sulphathiazole 1/100,000 and to sodium sulphapyridine 1/10,000.Technique. The size of (uncrowded) colonies on a plate containing 1/10,000 sulphanilamide or sodium sulphacetamide is a useful criterion of resistance or non-resistance, but a resistant strain must be able to grow on 1/5000 Sa and will not grow on 1/5000 Ssac.The best culture medium for these tests is Lab. Lemco bouillon with agar, but without peptone.In concluding I wish to express my thanks for their help to Prof. H. R. Dean, Prof. C. H. Browning, Drs E. T. C. Spooner, A. MacDonald, J. E. McCartney and R. D. Stuart. The sulphonamides I received through the kindness of the British Pharmacopoeial Commission and of Messrs May and Baker.
The bacteriology of dehydrated vegetables
Authors: Rishbeth J. 
Published: May 2009

Considerable errors arose when the plate count method was used to determine the number of bacteria on dehydrated vegetables. Bacteria probably occurred on the surface of the vegetables only.Plate counts tended to be greater when suspensions were prepared at higher temperatures over the range 10–40° C. Counts often increased by 20% and sometimes by 50% in the short period allowed in the standard procedure (25 min.), probably owing to multiplication of bacteria. Changes in the volume of suspensions, caused by rehydration of vegetables, led to small errors for which allowance could be made. Larger variations in count arose from sampling errors through differences in the number of bacteria on individual strips and, to a lesser extent, through imperfect distribution of bacteria in suspensions. The relation of plate counts to the actual number of bacteria on the vegetables was uncertain.However, the error in counting a single sample (— 65% to + 150%) was appreciably smaller than that in counting successive samples from the same factory (about fivefold) and this in turn was less than the variation between different factories (up to a thousandfold). The plate count could therefore be used with some confidence as a general guide to the state of factory hygiene.The author is grateful for assistance given by Dr M. Stephenson, F.R.S., of the Biochemical Laboratory, Cambridge, and by Dr M. Ingram, Dr H. G. Wager and others of the Low Temperature Research Station, Cambridge.
Studies in the dynamics of disinfection IX. The effect of lethal temperatures on standard cultures of Bact. Coli. I. The nature of the probit-log survival-time relationship at pH 7·0
Authors: Jordan R. C. , Jacobs S. E. , Davies H. E. F. 
Published: May 2009

1. A study has been made of the probit-log survival-time relationship in a number of experiments in which whole standard cultures of Bact. coli were subjected to heat at temperatures ranging from 47 to 55° C.2. It is concluded that the whole mortality up to 99·99 % could not be covered by a single straightline relationship since the graphs are curves concave upwards and to the left.3. Between 95 and 99·99 % mortality the relationship approximated closely to linearity.4. Several individual experiments showed ‘humps’ in their curves. These, although always occurring at the same stage in time in the disinfections, varied in their probit levels.5. By combining the data for all experiments, an idealized probit-log survival-time curve was obtained in which the changes of slope were less marked than in the curve representing the disinfection of similar cultures by phenol.The authors wish to express their gratitude to Messrs I.C.I. (Pharmaceuticals) Ltd. for their valuable financial assistance, which has enabled one of us (H. E. F. D.) to devote his full time to this work.
Post-partum breeding in the guinea-pig
Authors: Rowlands I. W. 
Published: May 2009

Information relating to post-partum mating has been described in guinea-pigs kept in six small colonies containing variable numbers of the sexes running together continuously in floor pens of standard size. Litters were born on the floor and rearing was communal (Method 1). Three other like colonies were similarly maintained, except that the females in late pregnancy were separated from the male to avoid post-partum mating (Method 2). The conditions of farrowing and rearing were similar to those of Method 1. The data given by thirty-four sows of a closely recorded (stock) colony bred in units of six females and one boar, but in which every litter was born and reared under ‘cage’ conditions (Method 3), were used for comparative purposes only.Post-partum mating was considered to have occurred only when the interval between the births of any two consecutive litters of the same sow did not exceed 70 days. Of litters born under Method 1, 80% were conceived at post-partum oestrus; the mean gestation period was 68 days. The average inter-parturition interval of all sows breeding under Methods 1 and 2 was 74 and 118 days respectively. The optimal ratio of the sexes in a colony breeding by both methods was judged to be twelve females to one male.Litter size varied between 3·98 (Method 1) and 3·69 (Method 3) and by all three breeding methods, the proportion of young already dead or that died at birth was about 5%. Deaths were more common in summer months when litter size was maximal.The post-natal death-rate during the first 28 days of life among young reared communally (Methods 1 and 2) was 10% and was fivefold that observed in litters reared separately by their mothers (Method 3). This death-rate was highest during the winter months due to the difficulty of providing adequate amounts of fresh green vegetables.The annual output of young guinea-pigs from colonies bred under Method 1 was 62% greater than that from other colonies bred by Method 2. The more rapid sequence of littering did not affect the quality (body weight) of the young at birth or at weaning.Attention has been drawn to a possible deleterious effect of intensive breeding to the health of the females and their lessened resistance to infection. It has been suggested that, for this reason, the breeding life of the sows should be limited to 1 year.