Showing papers in "Nature in 1948"

A new microscopic principle.

Abstract: IT is known that the spherical aberration of electron lenses sets a limit to the resolving power of electron microscopes at about 5 A. Suggestions for the correction of objectives have been made ; but these are difficult in themselves, and the prospects of improvement are further aggravated by the fact that the resolution limit is proportional to the fourth root of the spherical aberration. Tnus an improvement of the resolution by one decimal wotild require a correction of the objective to four decimals, a practically hopeless task.

Theory of the Stability of Lyophobic Colloids

Abstract: MANY of the classical investigations of colloidal chemistry were concerned with the stability of colloidal solutions of insoluble substances, such as gold, arsenic sulphide, silver halides, etc. The well-known phenomenon of coagulation of these sols by comparatively small concentrations of electrolytes suggested that their stability was connected with their electric charges. A considerable amount of research has been made in the past to discover the magnitude and origin of the electric charge on the particles and the nature of the electrical double layer which exists around them in salt solutions. Although qualitative and semi-quantitative explanations have been given of the phenomenon of coagulation and of the rule of Hardy and Schulze, according to which the ionic concentration required for precipitation diminishes rapidly with the charge of the effective ion, yet a complete and satisfactory theory was still lacking. Theory of the Stability of Lyophobic Colloids The Interaction of Sol Particles having an Electric Double Layer. By E. J. W. Verwey and J. Th. G. Overbeek., with the collaboration of K. van Nes. Pp. xi + 205. (New York and Amsterdam : Elsevier Publishing Co., Inc. ; London : Cleaver-Hume Press, Ltd., 1948.) 22s. 6d. net.

A Text-Book of Practical Organic Chemistry

Abstract: DR VOGEL‘S books on analysis are widely used in teaching practical inorganic chemistry His new volume is intended as a comprehensive laboratory manual for students of organic chemistry It gives a full and valuable description of organic chemical technique, details of preparation of more than six hundred compounds, and a scheme of qualitative organic analysis There are appropriate notes on the preparative reactions described and on the properties of the various classes of organic compounds A curious omission is the almost complete absence of reference to quantitative organic analysis It seems to the reviewer that some practice at least in quantitative elementary analysis is of value in the student‘s training, even in these days when the fully fledged organic chemist hands his analysis specimens to the microanalyst for determinations which he is usually quite unable to carry out himself A Text-Book of Practical Organic Chemistry Including Qualitative Organic Analysis By Dr Arthur I Vogel Pp xxiii + 1012 (London, New York and Toronto : Longmans, Green and Co, Ltd, 1948) 42s net

Order of Stability of Metal Complexes

Abstract: MELLOR and Maley1,2 have recently pointed out that the stability of complexes of bivalent metal ions follows the order

Origin of cosmic rays.

Abstract: IT is important to decide whether or not the main sources of the cosmic ray particles are external to our galaxy. An external source seems, at first sight, to be established by the observed isotropy of the cosmic rays incident on the earth. But it has been claimed by a number of authors that this isotropy is simply a consequence of a magnetic field assumed to exist in interstellar space. The basis for this claim is that a single particle of energy n and charge e is deflected through an appreciable angle after travelling a distance d across a magnetic field of intensity H, provided For n equal to 1010 eV., e equal to the electronic charge (4·77 × 10-10 E.S.U.), and d equal to the radius of the galaxy (∽3 × 1022 cm.), the necessary value of H is about 10-15 gauss. This value may be compared with the average interstellar field of about 10-20 gauss that would result if (i) every star possessed a magnetic moment equal to the commonly quoted magnetic moment for the sun (∽ 1·5 × 1034 C.G.S.) ; (ii) the stellar magnetic dipoles were all aligned parallel to each other.

Pathology of Tumours

Abstract: IN all branches of biology where the experimental method, and the co-operation of the chemist and the physicist, are extending our knowledge of living things, it is still essential for the results of morphological inquiry not only to be preserved but also to be reviewed, summarized and restated in the light of contemporary opinions. The descriptive morphologist acquires his knowledge and judgment by long experience, which no interloper, however gifted with modern techniques, can hope to achieve in a short space of time as a subsidiary interest. This is particularly the case with microscopical work, where sound interpretation of the visual image usually requires long experience and training. Pathology of Tumours By Prof. R. A. Willis. Pp. xxiii + 992 + 52. (London: Butterworth and Co. (Publishers), Ltd., 1948.) 63s. net.

Smoothing Periodograms from Time-Series with Continuous Spectra

Abstract: IN his review1 of M. G. Kendall‘s brochure2 on oscillatory time-series, David G. Kendall made the pertinent observation that the smoothing of periodograms obtained from autoregressive or other time-series with continuous spectra is equivalent to considering the first few sample autocorrelations. I had arrived at a similar conclusion, though possibly by an alternative route, having noticed that the averaging of periodograms obtained from contiguous lengths of series is approximately equivalent to a truncation of the correlogram at a point represented by the length of the subseries. From preliminary computation already made on M. G. Kendall‘s artificial series to test out this smoothing device, it appears promising.

Interpretation of experiments on metabolic processes, using isotopic tracer elements.

Abstract: IN two instances, the distribution of isotopic carbon in the product of a metabolic process has been used to infer that a symmetrical intermediate compound is not involved. Wood et al.1 showed that isotopic carbon, introduced as carbon dioxide together with pyruvate, led to the formation of ketoglutarate which contained isotopic carbon only in the carboxy group next to the keto group; on these grounds, they excluded citrate as an intermediate. Sbemin2 found that when glycine is formed from serine, containing isotopic nitrogen and isotopic carbon in its carboxy group, the relative abundance of nitrogen-15 and carbon-13 in the glycine was the same as in the serine; he argued that amino-malonic acid is therefore not an intermediate in this process.

Evolution of the Universe

Abstract: IN checking the results presented by Gamow in his recent article on "The Evolution of the Universe" [Nature of October 30, p. 680], we found that his expression for matter-density suffers from the following errors : (1) an error of not tailing into account the magnetic moments in Eq. (7) for the capture cross-section, (2) an error in estimating the value of α by integrating the equations for deuteron formation (the use of an electronic analogue computer leads to α = 1), and (3) an arithmetical error in evaluating ρ0 from Eq. (9). In addition, the coefficient in Eq. (3) is 1·52 rather than 2·14. Correcting for these errors, we find The condensation-mass obtained from this corrected density comes out not much different from Gamow‘s original estimate. However, the intersection point ρmat. = ρrad. occurs at t = 8·6 × 1017 sec. ≌ 3 × 1010 years (that is, about ten times the present age of the universe). This indicates that, in finding the intersection, one should not neglect the curvature term in the general equation of the expanding universe. In other words, the formation of condensations must have taken place when the expansion was becoming linear with time.

Order of Stability of Metal Complexes

Abstract: IN a recent communication1 it was pointed out that the order of stability of a series of internal metal complexes is substantially the same whether the metals are combined with bidentate chelate molecules like salicylaldehyde, glycine or 8-hydroxyquinoline. There is evidence from the results of other workers2,3 that the same order is to be found with complex cations and with internal complexes formed with quadridentate chelate molecules. Cations containing ethylenediamine have been studied by Bjerrum2,4 and Carlson, MeReynolds and Verhoek3. From the accompanying table, which shows the overall stability constants for salicylaldehyde and ethylenediamine complexes, the similarity of order in the two cases is evident.

Crystal Structure of Polyvinyl Alcohol

Abstract: IT has often been said (by me1 as well as by others) that the molecular repeat distance (from X-ray diffraction photographs) of polyvinyl alcohol—2·52 A.2—indicates not only that the chain has a simple plane zigzag configuration, but also that all the hydroxyl groups (in the section of a molecule in one crystallite) lie on the same side of the zigzag plane. This is not necessarily true ; so far as X-ray diffraction is concerned, the observed repeat distance is equally compatible with a molecular structure in which hydroxyl groups are randomly placed in left-and right-hand positions. This possibility was not considered until recently ; it was assumed that the high degree of crystallinity of polyvinyl alcohol implied regularity of molecular structure. Recently, however, it has been found3 that interpolymers of ethylene and vinyl alcohol are crystalline ; thus hydroxyl groups may replace hydrogen atoms at random on a carbon chain without destroying crystallinity ; the high crystallinity of polyvinyl alcohol cannot, therefore, be regarded as evidence against the idea of stereochemical irregularity in this molecule.

Physical Chemistry Of Process Metallurgy

Abstract: THE discussion on "The Physical Chemistry of Process Metallurgy", which the Faraday Society held at Ashorne Hill, Warwickshire, during September 23-25, showed plainly that process metallurgy is now as much the province of the physical chemist as the metallurgist. Attention at this meeting was devoted almost entirely to the high-temperature processes involved in the winning and refining of metals, and here in particular it seems that advances will come mainly from the application of physical chemistry. Indeed, speaking as a steelmaker, Sir Andrew McCance (Colvilles, Ltd.) confirmed, in his introductory remarks, that the advances in the open-hearth process over the past twenty years have come almost entirely from the physico-chemical approach to open-hearth reactions. In this article it is intended to touch only upon the main topics of physico-chemical interest. In so short a space it is impossible to consider all the problems discussed, and reference will not be made to those papers concerned with industrial applications.

Our Inner Conflicts

Abstract: MANY attempts have been made to modify the original Freudian technique and theories regarding the origin and treatment of neurosis. This book describes the variations which Dr. Horney has developed and gives an outline of her views on psychology, which are interesting and coherent. The first thing which strikes the reader is that the analyses she records are not transference analyses in the Freudian sense at all and, in fact, the word ‘transference' does not appear in the index. She does not believe, with Freud, that neuroses are caused by some distortion of the instinct but that they are the product of abnormal personality. She thinks that anxiety is produced by isolation, for example, and not by castration fears or birth trauma ; that obsessions are due to disturbed personal relationships and not to repressed sadistic impulses, and so on. Her views on personality are individual also. She believes that there are three types : (1) compliant, (2) aggressive, (3) detached. They are really devices to deal with the patient‘s basic anxiety. This anxiety is also avoided by idealization of the ego, so that the patient is able to see himself as more perfect than he really is. The neurotic conflicts, she thinks, often lead to diversion of energy from useful channels, so that there is an impoverishment and inertia, the final stages of which are an all-pervading feeling of hopelessness. Our Inner Conflicts A Constructive Theory of Neurosis. By Dr. Karen Horney. Pp. 250. (London : Kegan Paul and Co., Ltd., 1946.) 10s. 6d. net.

The Geography of the Flowering Plants

Abstract: THIS book, as the author himself states, "is devoted to plant geography in the narrower sense", plant ecology being outside its scope. As a consequence, the treatment is essentially factual in character rather than causal, and static rather than dynamic. The difficulties of any attempt at such restriction are at once apparent, despite the inclusion of chapters on geological history and plant distribution and a section devoted to the factors of distribution. However, within these limits the author has collected together many of the facts concerning the distribution of taxonomic aggregates over the earth‘s surface which will be a welcome addition to the botanist‘s library, the more so that much of the literature of the subject is widely scattered. More than a third of the text is devoted to salient facts of the distribution of families, genera and species, where many of the striking features of extended range, discontinuity and endemism are assembled and illustrated with more than forty maps portraying various types of occurrence, from the extended tropical range of the Palmae and the cosmopolitan genus Drosero, to the discontinuity of the Magnoliacese or that of Saxifraga geum and Dabœcia polifolium. The Geography of the Flowering Plants By Prof. Ronald Good. Pp. 403 + 25 plates. (London, New York and Toronto: Longmans, Green and Co., Ltd., 1947.) 30s. net.

Phthalocyanines as Semiconductors

Abstract: IN recent years Szent-Gyorgyi has directed attention to the possible importance of the electrical properties of organic molecules in biochemical catalysis1 and has given evidence for photoconductivity in gelatin2. An approach to the theory in trans-conjugated polyenes has been indicated by N. S. Bayliss3. Hoping to obtain a system suitable for quantitative investigation, I have examined the electrical conductivity of two phthalocyanines. These substances, described by Linstead and co-workers4, form a group of conjugated structures closely related to the biologically important porphyrins. They are particularly suitable for a research of this kind, because of their high degree of involatility and thermal stability. Their crystal structures are known from the work of J. M. Robertson5.

The evolution of the universe.

Abstract: THE discovery of the red shift in the spectra of distant stellar galaxies revealed the important fact that our universe is in the state of uniform expansion, and raised an interesting question as to whether the present features of the universe could be understood as the result of its evolutionary development, which must have started a few thousand million years ago from a homogeneous state of extremely high density and temperature. We conclude first of all that the relative abundances of various atomic species (which were found to be essentially the same all over the observed region of the universe) must represent the most ancient archaeological document pertaining to the history of the universe. These abundances must have been established during the earliest stages of expansion when the temperature of the primordial matter was still sufficiently high to permit nuclear transformations to run through the entire range of chemical elements. It is also interesting to notice that the observed relative amounts of natural radioactive elements suggest that their nuclei must have been formed (presumably along with all other stable nuclei) rather soon after the beginning of the universal expansion. In fact, we notice that natural radioactive isotopes with the decay periods of many thousand million years (such as uranium-238, thorium-232 and samarium-148) are comparatively abundant, whereas those with decay periods measuring only several hundred million years are extremely rare (as uranium-235 and potassium-40). If, using the known decay periods and natural abundances of these isotopes, we try to calculate the date when they have been about as abundant as the corresponding isotopes of longer life, we find that it must have been a few thousand million years ago, in general agreement with the astronomically determined age of the universe.

Particle-size Measurement

Abstract: I HAVE recently had occasion to devise a scheme for measuring the mean diameters of the particles of a powder. The method finally evolved has not been discovered during an examination of the available literature, and in view of its simplicity seems to merit description.

Physiology of Man in the Desert

Abstract: THE possibility that American troops might be required to fight in the desert caused a team of physiologists to go to the Colorado Desert in California during the summers of 1942 and 1943. Their efforts were mainly concentrated first on the effects of the environment and level of physical activity on the rate of sweating and on the water requirements of man, and secondly, on the physiological effects of water depletion. Physiology of Man in the Desert By E. F. Adolph and Associates. (Monographs in the Physiological Sciences.) Pp. xiii + 357. New York and London: Interscience Publishers, Inc., 1947.) 39s.

Purification of anti-pernicious anaemia factors from liver.

Abstract: WE have now prepared from ox liver two red pigments both highly active in pernicious anaemia. The crude extract was purified by the methods employed by Emery, and Parker1 and then by repeated chromatography. Full details of these techniques will be offered for publication later. Recently we have used as starting material a proteolysed liver extract made on a manufacturing scale ; this has given better yields of a product differing slightly in chromatographic behaviour, and of higher activity. Some preparations of both types have been separated by partition chromatography into two red fractions ; the proportions suggest that one arises from the other by proteolysis.

Feret‘s Statistical Diameter as a Measure of Particle Size

Abstract: VARIOUS measures of the size of irregularly shaped particles as seen in profile under the microscope have been used, chosen according to their theoretical significance or practical ease of measurement. These include, using Heywood‘s notation1,2 : (i) the diameter of the circle of equal area, d ; (ii) the diameter of the circle of equal perimeter, D ; (iii) the length of line bisecting the profile area (Martin‘s statistical diameter3), M ; and (iv) the perpendicular distance between parallel tangents touching opposite sides of the profile (Feret‘s statistical diameter4), F. M and F are determined for randomly oriented particles, thus giving an average value over all possible orientations. d is usually regarded as the ideal measure of particles seen in profile, but is somewhat difficult to determine experimentally with precision. It is, however, common practice when sizing very small particles to estimate d visually by comparing them with standard reference circles on a Patterson and Cawood or similar type of eyepiece graticule5,6. M and F are convenient to measure in practice with aid of an eyepiece scale or filar micrometer, and have been extensively used by various Workers. D, or rather the ratio D/d, termed by Heywood1 the ‘contour ratio', and its reciprocal called the ‘degree of circularity' by Wadell7, have been used in discussing the shape and hydrodynamical properties of particles. For these purposes D has usually been determined by direct perimeter measurement of the projected images of particles. It does not appear to have been adopted intentionally in any work known to me as a direct single measure of particle size.

The Chrysanthemum and the Sword

Abstract: IN her recent book, "The Chrysanthemum and the Sword", Dr Benedict deals with the Japanese along lines similar to, if not as clearly defined as, those in her earlier "Patterns of Culture" To quote Prof Franz Boas, she "is concerned rather with the discovery of fundamental attitudes than with the functional relations of every cultural item" These fundamental attitudes, she believes, colour and condition the whole of Japanese outlook and behaviour The Chrysanthemum and the Sword Patterns of Japanese Culture By Ruth Benedict Pp vii + 324 (London : Seeker and Warburg, Ltd, 1947) 12s 6d net

Quantitative paper chromatography.

Abstract: WE have recently developed a simple method for quantitative assay of amino-acids on the paper partition chromatogram. The method is in all probability applicable to any class of substance which can be readily located by means of a sensitive colourreaction on paper. Several technical points of general interest have arisen in the course of the work.

The Cultural Background of Personality

Abstract: THE late C. P. Scott and H. W. Nevinson were once exchanging stories which had never been printed ; Nevinson complained ruefully that when he was sent to report the ‘Black and Tans' in Ireland, he was shot at by both sides. Prof. Linton takes a greater risk ; in his brave attempt to cross-fertilize several different studies, he may be attacked from three sides. Obviously he cannot be ignored. The Cultural Background of Personality By Prof. Ralph Linton. (International Library of Sociology and Social Reconstruction.) Pp. xii + 102. (London: Kegan Paul and Co., Ltd., 1947.) 10s. 6d. net.

Principle of a counter-streaming centrifuge for the separation of particles of different sizes.

Abstract: WHEN a liquid containing suspended particles of uniform density streams through a conical tube, the velocity of the particles is greatest at the apex of the cone and decreases in the direction of the base. If the tube is placed in a centrifuge with the apex pointed away from the centre of rotation, in the direction of which the liquid is made to flow, the particles acquire, in addition to the velocity due to the liquid stream, a velocity in the opposite direction owing to the centrifugal effect. If Z is the distance between the apex and the centre of rotation, R the radius of the cone at the distance L from the apex, V the volume of liquid passing across any section of the tube in unit time, and x the distance from the centre of rotation, then the streaming velocity ƒ over any cross-section of the tube is The velocity of the particles in the direction away from the centre of rotation, however, increases linearly with the distance from the latter. In a certain cross-section (e) the two velocities are equal for a given particle size. Particles of this size situated centripetally from e are transported in the centrifugal direction and vice versa. Thus, when dynamic equilibrium has been attained, they have been accumulated in a very short section of the tube. Other particles are similarly accumulated in sections characteristic of their sizes ; the smaller their radii (r), the nearer the centre of rotation are their planes of equilibrium. The distribution of these planes along the radius of rotation is derived from Stokes' law and the above expression for the streaming velocity : where n is number of revolutions per min., η is viscosity of liquid, S is density of particles, S' is density of suspension medium. For x = Z/3, r has a minimum value :

Staphylokinase; an activator of plasma protease.

Abstract: SEVERAL workers1 have reported the lysis of fibrin clots by staphylococci, and this has been assumed to be due to a fibrinolysin produced by the bacteria.

The Study of Plant Communities

Abstract: SINCE plant ecology first started, as a distinct division of study within the major science of botany, with the publication of Warming's "Plantes-amfund" in 1895 (first German edition in 1896 and an English edition, "Oeeology of Plants", Oxford, 1909), it has owed much of its rapid growth to American workers. In particular, the concept of succession was clarified and systematized, if not conceived, in the United States, and its development has been stimulated and largely directed by the researches, terminology and theories of American ecologists. It is therefore to be expected that textbooks of ecology intended primarily for American students should record progress periodically. Such works naturally have both peculiar value and particular limitations for students in other countries. They direct attention to points of view and literature which might otherwise be overlooked and to examples which might remain unknown. On the other hand, it is not always easy to evaluate the conclusions reached because of unfamiliarity with both the flora involved and the field conditions. The Study of Plant Communities An Introduction to Plant Ecology. By Prof. Henry J. Oosting. Pp. 389. (San Francisco : W. H. Freeman and Co., 1948.) 4.50 dollars.

The Genus Crepis

Abstract: THE appearance of Babcock‘s monograph after four years delay in the press, due doubtless to the War, is an event of considerable importance, not only to botany but also to the biological sciences in the widest sense. Familiar as are parts of it to specialists, through the publication of numerous papers during a period of over twenty-five years, the collation of all this work in monographic form should bring it into the hands of a far wider circle of readers. The Genus Crepis By Ernest Brown Babcock. (University of California Publications in Botany, Vols. 21 and 22.) Part 1: The Taxonomy, Phylogeny, Distribution and Evolution of Crepis. Pp. xii + 198. 3.50 dollars. Part 2: Systematic Treatment. Pp. x +199–1030 (36 plates). 10 dollars. (Berkeley and Los Angeles: University of California Press; London: Cambridge University Press, 1947.)

International Union of Crystallography

Abstract: THE, first meeting of the International Union of Crystallography, which was held at Harvard University during July 28-August 3, provided an opportunity for the presentation of papers on many research projects that are being carried out in different parts of the world. More than seventy such papers were read, and there were many detailed discussions.

Correlation between Lewis Blood Group and Secretor Character in Man

Abstract: A NEW blood group character, designated as 'Lewis', was first described by Mourant1, who found that the blood of 25 per cent of English people contained the Lewis factor, and that this group character is independent serologically of the ABO, MN, Rh, P, Lutheran and Kell systems. Somewhat later, Andresen2 described 'anti-L sera' which are now known to be anti-Lewis sera. These sera agglutinated the red cells of 21 per cent of adult Danes and the cells of about 70 per cent of Danish children less than seven months old. Andresen put forward the view that the Lewis blood group was inherited by means of two allelomorphic genes L and 1, the three possible genotypes being LL, LI and II. The data observed indicated that anti-Lewis serum agglutinates the red cells of adults if they are of genotype LL only, whereas in young children the genotype LI is also detectable.