(1) The graphic method is more easy of application and requires less mathematical knowledge than the extended analytical method.

(2) In our experience it produces smooth curves of px and Ex.

(3) The analytical in the selection of the best process of interpolation appeals to the graphic method.

(4) While either the analytical or graphic process may in unskilful or careless hands give erroneous results, owing to errors in working out, the analytical process, unlike the graphic, presents a wide choice of methods, which although accurately worked out, give incomparable results.

(5) The facts given in the table on page 321 and in Fig. 1 A and B and table on page 317 show that almost identical results are obtained by the graphic method and by the improved extended analytical method. We regard this as important testimony to the accuracy of each of these methods, and at the same time as indicating the inaccuracy of the analytical methods giving different results.

(6) As the results obtained by the modified short analytical method and by the combined analytical and graphic method approximate so closely to those obtained by the detailed graphic method, either of them may safely be adopted by those who cannot spare time for working out a detailed Life Table by the graphic method.

(7) Every published Life Table should give exact details of the method of its construction, in order that the comparability of data and results may be tested. Much confusion has arisen, and important errors in comparison between different Life Tables have been produced, by the use of different methods of construction and the non-publication of details of methods.

In the Berkefeld filtration of a fresh guinea-pig serum, adsorption on the filter surface takes place, and the serum passes unaltered, if the saturation of the adsorbing surface has become complete.

This adsorption involves most probably first the albumins, which process then secondly influences the filtrability of the globulins. It is also shown that the physical conditions of the serum as regards salt concentration and dilution as well as H.-concentration modify the effect of filtration to a large extent.

Two outbreaks of salmonella food poisoning are described. In one, involving 55 persons, the infecting organism was Salmonella reading, and in the other, involving 39 persons, S. tennessee. In both, epidemiological and bacteriological evidence pointed to imported cans of cooked meat as the source. The role of contaminated shop equipment in furthering the spread of infection is particularly emphasized.

Attention is drawn to the severity of the symptoms and prolonged excretion of the organism in a number of the patients infected with S. reading.

In analysing some samples of air which had been sent for examination, the writer was struck by the presence of an altogether abnormal quantity of carbon dioxide associated with a very much diminished oxygen content. In view of this excess, the space from which these samples had been obtained was then thoroughly ventilated and after remaining closed for only four days the air was found to contain already 2·27 p.c. of carbon dioxide instead of the normal 0·03 p.c. No immediate explanation of the phenomenon was available and this paper contains a short account of the research made to discover the cause.

In this paper the term B. coli is used in its most restricted sense, and as implying organisms having all the characters of the typical B. coli communis. It is a well-ascertained fact that B. coli, even when the term is so restricted, exhibit very varying virulence.

The aim of this study was to evaluate potential sampling strategies for detection of infected flocks that could be applied during an outbreak of low pathogenicity notifiable avian influenza (LPNAI) initiated in duck holdings, following initial detection. A simulation model of avian influenza virus transmission and spread within and between holdings, respectively, was used to predict the impact on the size and duration of an outbreak of (i) changing the tracing window within which premises that might be the source of infection or that may have been infected by the index premises were sampled and (ii) changing the number of birds sampled in the flock being tested. It has shown that there is potential benefit in increasing the tracing window in terms of reducing the likelihood of a large outbreak. It has also shown that there is comparatively little benefit from increasing the number of birds sampled per flock.

The experience of the last few years in the Westphalian coal-field has shewn that the presence of Ankylostoma in a mine may become a matter of considerable industrial importance. Since it has been shewn that several of the metalliferous mines in Cornwall are throughly infected, the question of how far it may be present in, or spread to, other British mines has arisen in a practical form. When any large number of individuals have to undergo a medical examination for any such purpose it is of importance that such examination should be convenient at once for the examiner and for the examinee, that it should occupy as short a time as possible, and should, at the same time, be reliable. The diagnosis of the presence of Ankylostoma is commonly made by searching for the characteristic eggs in the faeces; and indeed a final diagnosis must rest in nearly every case on the results of this procedure. Which is therefore not easily replaced by any other method when separate individuals are in question. But as applied to a large body of active working men this process has many disadvantages, and at the request of the Home Secretary an inquiry has been made into the practicability of other methods of examination1.

The immediate dispersal of a fluid delivered to anaesthetized mice by the intranasal and intra-oral techniques has been studied by means of a radio-active tracer method. The results clearly show that the intra-orally inoculated animal accepts a larger proportion of the total volume inoculated and that a significantly higher fraction of this reaches the lungs than in mice inoculated by the intra-nasal technique.

The authors would like to thank Dr I. Friedmann and Dr H. A. B. Simons for having made this work possible; also, Mr D. Arnott for a generous gift of labelled di-iodofluorescein, and Dr D. A. Osborn and Dr K. Weinbren for helpful suggestions.

A total of 375 separate sampling experiments were performed on groupings of 100 samples each from distinct binomial populations in order to obtain estimates of the frequency of rejection of the hypotheses of homogeneity against alternatives of a trend by means of the usual χ2 or binomial index of dispersion test. These artificial realizations are presented in Figs. 1–5, and compared graphically with corresponding non-central χ2 distributions.

The authors would like to acknowledge the technical assistance of the Research Computer Laboratory of this University in programming and supervising the computational phases of this investigation, which was partially supported by the State of Washington Initiative 171 Funds for Research in Biology and Medicine and the Boeing Employees' Good Neighbor Fund.

The sex ratios and the emergence patterns of the European rabbit flea bred under animal house conditions were examined. An overall preponderance of female fleas was found. This was due to the greater preponderance of female fleas in the primary emergence, whereas the sex ratios in the secondary emergence were about 1:1.

From these two series of experiments we can conclude that a cowdung floor, grossly contaminated with a virulent culture of B. pestis, can retain its infectivity for 48 hours but not longer, and that a chunam floor, treated in the same way, does not remain infective even for 24 hours.

Since disinfectants containing hypochlorites have been used for the sterilisation of dairy utensils, and it has been claimed that such disinfectants are more efficient than steam sterilisation, it seemed advisable to study the question in the interests of the Milk Industry. The efficiency of three proprietary disinfectants (A, B and C) has, therefore, been investigated.

Formic aldehyde, the simplest possible aldehyde, is a substance possessed of considerable biological and chemical interest. Its biological interest consists in the fact that it has long been regarded as forming the first product of plant assimilation, and has recently been actually demonstrated as such in plants. The ease with which this substance undergoes polymerisation resulting in the formation of sugars, under the influence of simple reagents, justifies the assumption that formic aldehyde is an essential link in the building-up of complex carbohydrates by plants. In addition to this it has recently been requisitioned as the only possible source of proteid anabolism. Its interest to the physiological chemist is that it combines energetically with proteids, and to a less extent with carbohydrates, effecting considerable alteration of their physical and physiological properties. This behaviour seems to be directly antagonistic to the biological rôle ascribed to the substance above. This apparent anomaly of the same substance being both a poison and an essential physiological constituent of living cells is discussed by Loew. It seems to depend upon the fact that what may be termed the biological formic aldehyde is present in small quantities (dilute solutions) and is quickly used up, owing to the ease with which it polymerises or forms innocuous compounds. This last property has an immediate bearing upon the subject of this inquiry in so far as it may serve to explain the results obtained by the administration of small quantities of formic aldehyde to man in his food. It is in this connection that formic aldehyde is of interest to us, and the importance of this subject is in our opinion sufficient to justify us in reviewing somewhat exhaustively the results of other observers with regard to the chemical and physiological properties of this substance.

1. Extracts containing non-infective soluble antigens have been prepared from the tissues of mice infected with a pantropic or any of three neurotropic strains of Rift Valley fever virus. The antigens were detectable by complement-fixation and gel-precipitin tests using antisera prepared in mice.

2. The extracts appeared to contain at least two antigens separable by electrophoresis and distinguishable by Ouchterlony tests. The faster migrating minor antigen occurs sparsely and was not further examined.

3. No distinction, physical or immunological, was observed between the major antigen derived from the four strains.

4. In gel diffusion-filtration experiments with granulated 7 % agarose, the major antigen appeared to be polydisperse containing particles with diffusion rates ranging from at least as low as that of Burnupena cincta haemocyanin to almost as high as that of haemoglobin.

5. Centrifugal analysis indicated the presence of particles having sedimentation constants of about 8, 29 and greater than 100 Svedberg units. These particles have a density of about 1·27 g./ml. If all the particles of the major antigen are spherical, with a density of 1·27 g./ml., the three size groups have diameters of about 7–8, 14 and < 26 mμ.

6. The diffusion coefficient of the smallest particle was estimated to be 6·06x 10−7 cm.2/sec. corresponding to a sphere 7 mμ in diameter, or 4·78 x 10−7 cm.2/ corresponding to a sphere 9 mμ in diameter depending on which of two values for the diffusion coefficient of mouse γ-globulin is used in the calculation.

7. In density gradient zone electrophoresis at pH 8·6, the principal antigen migrated at about the same rate as haemoglobin and appreciably slower than the virus. The authors are indebted to Prof. A. Kipps for his continued interest in this work, and to Dr T. H. Mead for valuable criticism of this paper. This investigation was supported in part by a Public Health Service research grant Al 04044–02 from the National Institute of Health, Bethesda, U.S.A.

Anti-pneumococcal polysaccharide antibody (anti-PPS) levels were measured in 153 serum samples collected from children aged between 2 and 47 months living in the highlands of Papua New Guinea (PNG). Fifty-seven of the samples were collected during acute episodes of lower respiratory tract infection (ALRI). Total IgA and IgG increased steadily with age; however, no association was found between the levels of these antibodies and the health status of the child. Total IgM levels showed little relationship to the age of the child but under 12 months of age levels were somewhat higher on average in children with pneumonia. For most of eight pneumococcal serotypes tested, specific IgG levels were found to decline rapidly in the first 6–8 months, reaching a minimum at approximately 12 months of age. Serotype 3 was exceptional in having very low titres in the youngest children. A separate analysis of 24 cord sera suggested that antibodies to this serotype do not usually cross the placenta in PNG. Children with pneumonia tended to have lower levels of specific IgG than healthy controls of the same age. Specific anti-PPS IgA levels were found to increase steadily with age, but were not associated with health status.

The appearance of specific hypersensitivity to virus antigens was examined in mice infected intravenously with vaccinia virus. Both immediate hypersensitivity, transferable by serum, and delayed-type hypersensitivity, transferable only by cells, were apparent 8 days after infection and demonstrable for at least a further 130 days. Production of macrophage migration inhibitory factor by lymphocytes from infected mice was measured directly in terms of inhibition of migration by antigen or indirectly by determining the effect of soluble factors elaborated by the stimulated lymphocytes. The irregular results may have been the resultants of antigen-mediated macrophage stimulation, toxicity and induction of migration inhibitory factor. Transformation of spleen cells – presumably lymphocytes – from infected mice could be induced in vitro by virus antigens for at least 139 days after infection. Virus/lymphocyte interaction appears to be a particularly fruitful area for further study.

Hepatitis A infection results in a spectrum of illness from asymptomatic disease to severe fulminant hepatitis. Since 2000, <50 cases have been reported annually in Ireland. We report on an outbreak of hepatitis A associated with a childcare facility(CCF) in 2015 in Ireland. Between January and July 2015, 12 outbreak-associated symptomatic hepatitis A cases were identified, including one delayed, retrospective diagnosis. Seven (58%) cases were adults, eight (67%) were male, six of the adults required hospitalisation. All 12 cases were confirmed on serology and the four cases that were genotyped were identical on phylogenetic analysis. Potential environmental exposures and hygiene practices at the CCF were investigated. Outbreak control measures included the provision of: hepatitis A information, infection prevention advice, hepatitis A vaccination to 554 CCF contacts, and voluntary closure of the CCF for deep-cleaning and staff education. From a healthcare perspective1, outbreak control costs were in excess of €45 000. This outbreak illustrates the considerable adult morbidity that can occur in hepatitis A outbreaks, highlights the challenges in controlling a large CCF-associated outbreak and the importance of early recognition by clinicians of hepatitis A.

One hundred and twenty-nine samples of fresh cream collected in Worcestershire were examined bacteriologically. Sixty (46·5 %) creams had counts of over 100,000 bacteria/ml. The bacteria present were of many varieties, the commonest being Bacillus spp. (aerobic spore formers), Gram-negative bacilli, staphylococci and micrococci. Since most of the creams had been either pasteurized as cream or manufactured from pasteurized milk it was thought that the many bacteria were present because of contamination after pasteurization due to three main causes; unsatisfactory or unhygienic premises, unsuitable equipment, manual handling during the filling and capping process.

The methylene blue test results related well with bacterial counts but there were seven (5·4 %) anomalous results. Although the methylene blue reduction test therefore could serve as a simple and reasonable guide to the hygienic quality of fresh cream, 5·4 % of anomalous results would perhaps make it unsuitable as a statutory test.

We thank Mr R. Colenso, M.A.P.H.E., M.A.P.H.I., Chief Public Health Inspector, and Mr H. Beckett, Milk Sampling Officer of the Worcestershire County Council, for arranging the supply of samples.

There could be no more suitable preface to emphasise the need for Diphtheria prevention than the following quotation from so high an authority as the metropolitan Asylums Board's Report of 1924–25: “Notwithstanding the great improvement in diagnosis, standard of living, education in matters of hygiene and other public health measures, the fact remains that, for reason not altogether clear, diphtheria appears to be stregthening its forces and gathering power unchecked by science.”