1. The total reproductive performance of two groups each of twenty-four mice over a period of one year under two different systems of mating has been recorded.

2. In the first system (monogamous pairs) the male was kept continuously with the female; in 78% of cases the females became pregnant again at post-partum oestrus and were thus subjected for the most part to unbroken intensive breeding.

3. In the second system (polygynous groups) several females were kept with one male and were removed to individual cages for the birth and rearing of the litters and were returned to the male again only after the litter had been weaned.

4. Under the first system 1149 young were successfully reared to weaning in one year by the twenty-four females; under the second system 559 young were weaned during the same period.

5. Mortality of breeding females, litter size, weight of young at weaning, the effect of parity, loss of litters and of young between birth and weaning and the sex-ratio of the young weaned were alike for both methods of mating.

6. The interaction of concurrent gestation and lactation upon the length of the gestation period is discussed, and regression lines showing the relation between the number of young suckled, the number of young in the uterus and the length of the gestation period are given.

My best thanks are due to Dr A. S. Parkes, F.R.S., for advice during the course of the work and for help in the preparation of the manuscript. I should also like to thank Dr C. W. Emmens for the statistical analyses and the calculation of the regression lines.

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

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

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

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

I wish to record my grateful thanks to Dr E. S. Horgan, Assistant Director Research, Sudan Medical Service, for the help and advice given in the carrying out of these experiments and preparation of this paper and also to Col. H. T. Findlay for his helpful criticism and permission to quote the conclusions of his preliminary experiments.

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.

1. The types of resistance acquired by certain related strains of Str. cremoris as a result of phage action were investigated.

2. Some partially resistant forms of Str. cremoris were able to ‘carry’ phage in symbiotic association when subcultured daily in milk for long periods of time.

3. The phage ‘carrying’ power of the cultures was of a non-inherent nature. ‘Purification’ of the phage-carrying cultures by plating resulted in the production of phage-free colonies.

4. Under certain circumstances, the presence of symbiotic phage in a culture gave a measure of protection against attack by other phage races.

Due to earlier reports of the relative resistance of S. typhi and other members of the salmonella group to penicillin, and to the prevalent preoccupation of most workers with those organisms against which treatment with penicillin was more obviously applicable, little attention was payed to the chemotherapy of enteric fever until Bigger (1946) published his findings on the synergic action of a more reliable guide to the occurrence of synergism than sterilization, might be demonstrated. In conformity with the previous results, however, treated broth was also used to demonstrate synergic killing effect. Results are given in Table 12.

T455, when tested under similar conditions, was inhibited by 6·25 u./ml. penicillin and showed a twofold inhibitory synergism in the presence of sulphathiazole. It will be seen that all the strains tested showed some degree of inhibitory synergism but that, in the majority, the concentration required to inhibit growth was considerably higher than in the case of S. typhi. With the majority of strains the concentration of penicillin required to destroy the inoculum in 24 hr. at 37° C. was greater than 25 u./ml., even in the presence of sulphathiazole, while in one case no bactericidal synergism at all penicillin and sulphathiazole against S. typhi. Although, therefore, much work has been published concerning the synergic action of the sulphonamide group on penicillin activity in general, little information is available on the in vitro behaviour of the salmonellas in this respect despite the present wide, though tentative, application of the principle in the treatment of enteric fever. The experiments presented above were undertaken with the object of confirming those findings hitherto reported and of studying in detail the effects of sulphathiazole and penicillin, and of combinations of the two, on the salmonella group, with special reference to S. typhi.

For purposes of discussion it is convenient to summarize our results under the principal headings used in the text.

A study was made of factors leading to loss of working time in a local group of 144 women voluntary factory workers. The majority were single women whose interests centred in their families. One-third of these 144 women, owing to disability of some near relative, had home duties which they realized were sufficiently heavy to interfere at times with their factory work; a contributory cause of absenteeism was ill-health, ascribed by many workers to cold and draughty working environment. Examination of the factory records showed more than twice the rate of absenteeism due to certified sickness among women with home ties and responsibilities.

This study was made possible by the willing cooperation of the Factory Management and their Welfare Department and of the women workers concerned.

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

The titres of the complement-fixation test and the agglutination test run parallel in rabbit sera, but not in human sera. These facts are explained in connexion with the specificity of complement.

One object of the investigation was to determine the ideal contributions to warmth comfort in small ‘domestic’ rooms of air heating and radiation. It was soon found that in rooms heated by fires, subjects usually complained of cold backs when the equivalent temperature was in the region of 60–65° F., the accepted standard for buildings heated by convection, and preferred equivalent temperatures above 70° F.

Since large-scale trials, using many observers, were clearly necessary, the reliability of 5 min. test periods was studied; these short periods were proved reliable so long as the subject had previously been in a comfortable room for an hour or so.

It was found necessary, in rooms heated by fires, to treat separately the side of the subject facing the fire and remote from it. The cooler side must be exposed to an equivalent temperature not much less than 65° F., while radiation falling on the warm side is to be regarded as a very desirable, but nonessential, bonus. These conclusions were confirmed by field work in the subjects' own homes.

The eupatheoscope and globe thermometer were modified to enable conditions acting on the two sides of the body to be assessed separately.

The extent to which radiation acting on the front of the body could compensate for a cold back to produce what was called ‘minimum comfort’ was also studied. It was shown that down to back equivalent temperatures of about 56° F. an increase of 2° in front equivalent temperature will compensate for a fall of 1° in back equivalent temperature, but below 56° F. compensation fails.

The physical basis of sensations of stuffiness and freshness were also investigated. Throughout these experiments care was taken to ensure that the subjects were neither too hot nor too cold. In these conditions, only two factors appear to be important. First, the air temperature should be as low as possible. To obtain warmth comfort with a low air temperature some high temperature source of radiation is generally necessary. The peak wave-length of the radiation emitted by the fire is also of great importance, a striking change in the personal sensations occurring, for example, as the wave-length increases from 2 to 3μ. In general, those wavelengths which are absorbed in the outer layers of the skin cause sensations of stuffiness, and those which are not give rise to feelings of freshness. Peaks at 3, 4·1 and 4·7 μ should therefore be avoided in the design of gas and electric fires.

A Cope-Chat card has been designed and used for the recording and analysis of breeding performance in guinea-pigs.

Modifications required to adapt the card for use with other species are described.

Some general principles of colony management are discussed.

1. Treatment with enzymic hydrolysate of protein after blood depletion has a significant action in restoring serum protein content.

2. Blood depletion of hyperimmunized horses alters the serum globulin fraction much more markedly than the serum albumin fraction.

Our thanks are due to Dr R. N. Roy and Mr Diptish Chakraborty for useful help.

1. We have investigated bacteriologically the conditions in a central meals kitchen from which about 3000 meals were issued daily to some 65 departments.

2. Plate counts showed that the containers in which the meals were sent out contained large numbers of organisms, from several thousand to several hundred thousand per container.

3. Counts of this order were obtained both before and after the routine method of washing.

4. These counts were reduced to the order of a few hundred or less per container by steam sterilization.

5. Exposure for 2–3 min. to steam from a simple jet sterilizer was effective for all except large insulated lids which required at least 5 min.

6. Treatment for 5 min. in a chamber filled with steam from a boiler was effective with all types of containers and lids tested.

7. If containers are to be sterilized at all they must be sterilized each time they are to be used.

8. A great improvement in the bacteriological counts can be achieved by attention to the hygiene of washing, e.g. by the use of plenty of hot water with soap and soda or perhaps preferably with detergents, with a second sink of very hot water for rinsing, and by using fresh sterilized dish-cloths each time the washing water is changed.

9. Counts almost as good as those given by steam sterilization were obtained by washing with soap and water at 48–50° C., wiping with a sterilized dish-cloth and then rinsing in a second sink of water at 75–80° C.

10. The arguments for and against steam sterilization are discussed.

This investigation was greatly helped by the co-operation of the Leicester Education Department.

1. A cow given by the mouth very large doses of virulent typhoid bacilli (275 and 125 thousand millions) on two occasions at an interval of 29 days failed to show signs of infection or to pass the bacilli in faeces or milk.

2. Of two-month-old calves, dosed with about 100 ml. ascites broth culture of typhoid mixed with milk, one became infected and typhoid bacilli were grown from the intestine and ileocaecal gland. Both, however, passed typhoid bacilli in the faeces on the first or second day after dosing.

3. When large numbers of typhoid bacilli (say, 1–3 thousand millions) were instilled into the udder through the teat canal, excretion of the bacilli in the milk usually ceased within 10 days (fourteen quarters of four cows). In two quarters of one of these cows excretion continued for 25 and 27 days, and in two quarters of another cow for at least 85 days. The procedure usually caused an acute mastitis lasting for a few days, and the ‘H’ and ‘O’ agglutinin titre of the blood rose.

4. When large numbers of typhoid bacilli were applied to the teat orifice, even when this had been grossly injured beforehand by slitting the sphincter, there was as a rule only a very transient infection. In eleven cases out of twelve, either the organism could not be found in the milk or was found for 1 day only; in the remaining case there was intermittent excretion for 7 days.

5. The strain of typhoid used for most of the above experiments was of high Vi content and was isolated from the carrier involved in the Bournemouth-Poole epidemic of 1936.

6. These experiments do not support the view that milk-borne typhoid outbreaks are brought about by an active infection of the cow and suggest that the main object of the epidemiologist must still be the location of the human carrier.

7. The chances of typhoid bacilli growing in the milk after its withdrawal from the cow are stressed.

This work was rendered possible by financial assistance from the Ministry of Health and from United Dairies Limited. Thanks are due to Dr A. Felix for providing a Vi-rich culture of typhoid, and to Dr V. D. Allison for valuable help in checking the draft paper and making suggestions.

An analysis of the medical condition of 223 entrants to the nursing profession is attempted, with particular reference to 161 such nurses examined in accord with the recommendations of the King Edward's Hospital Fund for London (1943). This is followed by a short-term medical follow-up on these nurses by clinical examination, weight records, and ancillary tests. Of the total number of entrants eight (3·6 %) were rejected on medical grounds, and four (2·5 %) of the 161 were rejected on the findings of the initial examination.

An analysis of the sixty-five (29 %) nurses lost to the profession in their first year of service shows that 70 % had attempted an uncongenial vocation. It is suggested that vocation selection tests should be tried in attempting to lessen this costly drain of recruits. This figure of 29 % is no higher than the peacetime figure found by the Lancet Commission (Athlone Report, 1938).

An analysis of the illnesses of the nursing staff at Westminster Hospital during 3 years from 1 July 1943 to 30 June 1946 is presented, nearly 60 % of the illnesses being accounted for by respiratory tract infection and cutaneous sepsis. It has been shown that illness of more than 50 days in duration accounts for only 5 % of attacks of illness, but practically 30 % of the time lost through illness. It is suggested that such illness should be differentiated in analyses, from illnesses of shorter duration. A comparison of illnesses in staff nurses and student nurses follows; the figures suggest a lower morbidity rate in staff nurses, but the number of staff nurses is so small that the author cannot state that this has been demonstrated.

A comparison table between previous illness surveys and the present figures is presented which demonstrates a decreasing number of attacks of illness per nurse over the last 20 years in this country, probably due to better basic conditions of life.

A similar but international comparison applied to respiratory tract infection and cutaneous sepsis demonstrates that the former accounts for about 40 % of all the attacks of illness in this country and internationally. The previous figures for Great Britain, however, are exceptional in showing a much higher incidence of sepsis than elsewhere; this has not been substantiated by the present survey.

Figures for the amount of time lost per year through sepsis, tonsillitis and catarrhal disease are compared with those of Branson (1933) of 20 years ago, and perhaps illustrate the beneficial effect of surgery in cutaneous sepsis, and of sulphonamides in tonsillitis, as against the negligible therapeutic advances in catarrhal disease. The amount of tonsillitis sustained by nurses in the children's ward is shown as being out of proportion to the number of nurses employed.

Finally suggestions are made for promoting the health of nurses, which include: (i) the provision of a ‘welfare officer’ in the nurses' home; (ii) illness allowance proposals; (iii) remarks on the technique of ‘reporting sick’; (iv) staffing children's ward with senior nurses only.

1. Two men and four women carried out digestibility experiments on English and Canadian wheats at 90 and 80% extractions. The flour was the only source of protein and contributed 77−93% of the total dietary calories.

2. At 90% extraction the digestibility of the diets in terms of calories was unaffected by the source of the flour and amounted to 93·3%. At 80% extraction the digestibility of the diet containing English wheat amounted to 95·6% and of those containing Manitoba wheat to 96·7%. The difference is attributed to mild intestinal upsets on the English flour.

3. The apparent digestibility of the protein depended upon the amount of N in the wheat and fell as the extraction rose. A quantitative analysis of the results indicates that the protein in wheat flour of 90 and 80% extraction is completely digested and absorbed, and that the N found in the faeces is entirely derived from the secretions of the gut.

The Medical Research Council paid for the expenses of this investigation. We are very much indebted to Drs T. Moran, C. R. Jones and other members of the Cereals Research Station, St Albans, without whose help this study would hardly have been possible. We have also very much appreciated the help we have received from the subjects, Miss M. Costain, Miss C. M. Walsham, Miss E. Wilkinson and Mr R. Tayler, and also from Flt.-Sergeant Childs, who kindly made the bomb calorimeter determinations.

1. The 99·99 % mortality time (t) has been used as a measure of the rate of disinfection of standard cultures of Bact. coli by heat under carefully controlled conditions, and the relationship between this rate and temperature (T) over the range 47–55° C. has been examined.

2. From the form of the relationship a minimum temperature of about 44° C. for the reaction was indicated, but the formula t (T — α)b = a, which has been used for the calculation of biological temperature coefficients in the past, was quite inadequate to express the relationship when an acceptable value for the maximum temperature (α) was employed.

3. The formula t × θT = A more usually employed in bacteriological work, fitted the data reasonably well except at the highest temperature. The very high value of 897 for Q10 was obtained.

4. On theoretical grounds, the above formula could not apply at temperatures near the minimum, and also it appeared likely to break down when high temperatures were used.

5. It was shown that the full graph of log (t — 10) against temperature should be sigmoid and asymptotic to two temperatures, a minimum and a maximum, the latter being defined as the temperature at which 99·99 % mortality would be produced in 10 min.

6. The graph of the Pearl-Verhulst logistic equation is of this type and, with 44 and 56° C. as the minimum and maximum temperatures, it provided an excellent fit to the data, especially at the highest temperature used.

Studies in the Dynamics of Disinfection VIII. The effect of lethal temperatures on standard cultures of Bact. Coli. I. A Detailed Analysis of the Variations of Death-Rate with Time

BY R. C. Jordan, Ph.D., S. E. Jacobs, Ph.D. and H. E. F. Davies, B.Sc.

Table 3 (p. 142).

The heading of col. 2 should read

and the heading of col. 3 should read

Standard error of

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

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

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

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

I should like to thank Dr A. S. Parkes, F.R.S., for his help in the preparation of the manuscript.

The findings of clinical nutrition surveys of 3351 children aged 8–15 years and of 3326 adults, of both sexes, were analysed statistically to ascertain the relationship existing between nutritional grade (good, fair and poor) and the incidence of a variety of clinical signs (pityriasis, folliculosis, gingivitis, etc.) observed at the time of the medical examination but not taken into account in grading the subjects according to their state of nutrition.

The analysis showed negligible correlations between the clinical signs singly and collectively and the clinician's nutritional grade. Further, when we compared the incidence of each clinical sign and the nutritional state as a combination of all the clinical signs (i.e. the general nutritional factor), there was negligible agreement as shown by the low general factor saturation coefficients, thus suggesting that the presence of these signs is not a dependable expression of the general state of nutrition.

A special clinical survey of 1067 children was carried out to provide data which would throw light on the relationship between the criteria (posture, muscular development, etc.) which the clinician consciously takes into account but does not as a rule record in deciding the nutritional grade, and the nutritional grade itself. The grading criteria in the survey were separately assessed and recorded and so also were the usual clinical signs (pityriasis, gingivitis, etc.).

For the grading criteria there was a high degree of correlation between each one and the nutritional grade and also between each one and the combined pool of all the criteria. The clinical signs showed only negligible correlations with each other, with the nutritional grade or with any of the grading criteria.

It would seem, therefore, that nutritional assessment as at present understood is determined mainly by the value placed on the grading criteria (posture, muscular development, etc.), and to a negligible extent or not at all by the presence or absence of clinical signs (pityriasis, folliculosis, gingivitis, etc.).

Although the composition of blood is assumed to be constant within narrow limits, fluctuations in concentration of its constituents have been found by many observers over the period of a day or longer. Shaw (1927), Jores (1934) and others describe daily fluctuations in the white corpuscles, and Sabin et al. (1925) found similar changes in the blood platelets.