摘要:

"On the truth which Science has revealed, and is revealing, we build the new humanism of our age."-Dr. BARNES, Bishop of Birmingham. R ETURNING in 1925 from a world tour, 1R Haber, concerned with the economic plight of Germany, her lack of raw materials, the inconsiderable increase of agricultural efficiency, delivered this message to the German people: " Man kann namlich den Reichtum nicht nur aus dem Boden holen, sondern auch aus dem menschlichen Verstande." He declared this 'invisible item' of the national balance sheet, the trained human intelligence, to be of vital importance for the resuscitation of his country. He claimed, and rightly, that the German system of higher education has proved more effective than that of any other country in producing men of creative achievement in technical science; they are the geese which lay the golden eggs. That it has not failed in pure science is amply evidenced by the list of Nobel prizemen. He disclaimed any intelligence for his own people higher than in other countries; he attributed the success to the method by which the intelligence has been trained and then utilised, France being inferior in the higher education, England lacking co-operation between university and industry, America being deficient in depth and patience though replete with cash and equipment. How, indeed, is it with us ? In the ten years preceding the War we had made rapid strides in secondary and university education, during the War we envisaged still greater progress, but we chose the policy of the 'knock-out blow' and must wait for the fabric of the vision. Just seven years have slipped away since the Peace Treaty was signed, and we do not yet know whether our ship is slowly sinking or will right herself. Our cousins, over yonder, say we are ' down and out.' They relish exaggeration; yet who can study the events of 1926 and remain blind to the threat that Britain's days as the workshop of the world are numbered? The coal and iron and engineering genius, which together with our coast-line placed us far in the van of industrial development, can keep us there no longer, but our industrial population remains. Trained intellect alone can enable us to hold our own until the transformation of our social organisation shall have been accomplished without catastrophe. Trained intellect-not only, nor even chiefly, trained in technical science. It is true that science furnishes the key to Nature's storehouse of power, that the trained intellect has made man a creator, but of even greater importance is the use lie makes of the power and the kind of life he creates. Science is determining the material conditions; the new humanism must rise to the occasion and teach us how to live. Creative thought is what the world is needing in all departments of life; it will express itself in literature and other arts, and it will issue in new hope and energy in all ranks of society. The destiny of Great Britain, and even its immediate future, hang upon the success we can achieve in leading the right men to devote their lives to science, in supplying the needs for their work, and in permeating the nation with a sense of responsibility that the gifts of science shall not be misused. Great Britain has indeed been exporting much of its 'invisible item ' for many years to India and other parts of the globe, carrying the white man's burden. There are obvious signs that this export, like others, will diminish in the near future-no other country has suffered such a drain-and with this leak stopped, the home level may be expected to rise.No one can doubt that the talent is there. Does any one claim that we make the most of it ? The practical problem is beset with difficulties, complexities, incompatibilities. There is no single simple solution possessing all the virtues and omitting none; and time is precious. Ought boys to leave school and approach their university studies fresher in mind ? Is too early specialisation in schools a cause of sterility later; and when is too early ? Is our conception of the university as a sort of examination mill wholly mistaken, if not immoral, and the German plan wholly right, with its freedom from mark-grubbing, and only a viva voce on subjects subsidiary to a thesis ? And if not absolutely ideal, is it not at any rate more effective in developing the right man and discouraging the rest ? The fact is that we are even now engaged on a new synthesis in education, one which bids fair to spare the wheat and straw the chaff. Our national genius is not logical but practicallogic thrives on narrow premises. We have succeeded in producing a multiplicity of types of schools and universities, and rightly used this multiplicity will ease the problem; it may go far to solve it. The time between educational seed time and harvest is long, but intensive culture in the last years at school and during the university period may bring forth fruit in a few years. Further, school and university interact rapidly; the effect is like that of the 'reaction' on a radio receiving set, and if judiciously applied the result is harmonious amplification,' for the man fresh from the university brings new life back to the schools. Unfortunately, at present the effect of the university on some of the most promising boys is as though the coils were wrongly connected; we get not amplification but damping. Many a teacher, not alone the science master, knowing the keenness and capacity of his most brilliant scholars, has felt sick at heart as he noted the effect upon these boys of the enforced repetition of work done years before at school.The universities do their best to deal with the heterogeneous crowd that presents itself, but the lecturers are frequently overworked and underpaid and are possibly not adequately aware of the thoroughness and high standard of the teaching in many schools. They wearily resist all suggestion of exemption from the first-year courses, or complain that the students are packed with much knowledge but little intelligence Ought the boys to leave school earlier ? Some universities think they ought, and prefer them. not to have taken the higher certificate; others regard it as equivalent to their intermediate examination and grant exemption accordingly; some accept it in lieu of the first M.B. if the appropriate subjects are taken, and the reason is a good one, for it is based on the long period of later medical courses. Obviously the problem of the best development of a person is a personal matter, and whenever possible a personal solution should be sought; but schools and universities are institutions, and organisation is paramount. For the purpose of this discussion boys may be divided into the precocious clever and the slow-maturing capable. If the leaving age is eighteen or nineteen, as is usual in the best schools, both types will benefit greatly in character by the sense of responsibility developed in the last year of school life; this would not be very seriously reduced if all boys left a year earlier, for the responsibility would be the same; but if two years were cut off, the boys would not be mature enough and would lose something of great value. Going up to a university at nineteen, the clever boy finds he need not work hard in order to get a good degree, and may seize the wider social and educative opportunities of university life-he may seize them too hard if thwarted in his keenest interest, his life's work; the slower boy, faced by an examination test unsuited to his type, makes inconspicuous progress. If both boys were to go up at seventeen, the slow boy would have to work harder for his degree and the clever boy would do well in his examination, but both of them would have two more years to spend at the university free from the warping strain of examinations, free to develop under guidance along lines of natural inclination and innate abilitv. The fact that the two boys are being compared after the degree examination means that the clever boy has as good a chance as ever of showing what is in him, and the slower maturing boy is being given his chance, at the latest possible academic period and under the most favourable conditions of concentration, to show his capacity. A third plan suggests itself. If nineteen years were adopted as the leaving age, a two-year degree course might be a possibility, ending with an examination, but followed by two more years of post-graduate training of some creative kind and a thesis. The age at which specialisation should be allowed in schools might also be regarded as dependent on the precocity or otherwise of the boy. On the other hand, it is a matter of experience that the obvious development of the less precocious boy dates from the moment when he was allowed to specialise on a subject of his own choice. The precocious boy is quite usually, though not always, blessed with wide intellectual interests which continue throughout life, and concentration does him no harm. But something more may be required of the university than satisfaction with courses all severely scientific. All science students should be expected to attend at least one course such as philosophy, English literature, and history or economics, preferably in the post-graduate period when their minds will be free to enjoy them, and not for an examination test but for an essay. Similar courses in the sciences might prove of inestimable value for students in arts, if the right men were chosen to create them.At present, if a student goes up to the university younger than his competitors, he risks getting a poorer degree and making a poorer impression on his teachers, and with it he reduces his chance of post-graduate opportunities. While this remains so, it is scarcely fair to leave the momentous decision to the individual; the handicap is too heavy. One further point arises. The schools like to keep boys until nineteen years of age. The British type of university does, at least, produce science teachers whose enthusiasm and ability is a great asset to the country. Compared with German universities, where there is almost no routine teaching for degrees by examination and everything is ordered for what we treat as post-graduate work, the science staff of our universities is lamentably small, and the salaries much lower than in the schools. If the universities continue to have to provide instruction, which in Germany is done in the schools, by men who have in addition to master the mass of literature and prosecute research, they will need a corresponding increase of staff or find the task an impossibility. If the schools send their boys at seventeen, then possibly some of the science masters might return to the university with riper teaching experience than the ordinary lecturer can ever hope to acquire; but unless the university authorities cease to override the recommendation of the Treasury Grants Committee, they would do so at heavy pecuniary loss.The introduction of the Ph.D. degree has created a new situation: the universities must make adequate arrangements for post-graduate work. The crux of the question is the relative value to a man leaving the university at twenty-two years of age, of two more years at school or two years' post-graduate work at the university. Under one system the absorptive sponge may prosper, readily yielding its secreted information under pressure of examinations, but for the development of creative thought the post-graduate years are incomparably more fertile.

ISSN:0028-0836    

DOI:10.1038/119109a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

ATTEMPTS to construct theories about the N physical conditions inside a star need, of course, no excuse. Such theories are on the same footing as other physical theories, inasmuch as many intermediate steps will be inaccessible to the test of observation. They have, therefore, the right to a fair and serious judgment on a par with ordinary physical theories, according to agreement with observation, inner consistency, or beauty and simplicity. In his recent book Eddington attempts to give a complete review of current theories concerning the state of things in the stellar interior. This field of theoretical investigations was, in fact, first opened up seriously by Eddington himself not more than ten years ago; and although quite a number of investigators have entered the field since that time, still his own work predominates, and 'Eddington's theory ' has become a popular abbreviation for prevailing, and sometimes conflicting, views on this subject.The growth and development of the theory of matter under stellar conditions has, as might have been expected, run closely parallel to the growth of knowledge about atomic structure. Apart from the point stressed in Eddington's first paper on this subject, namely, that inside a star energy is primarily transferred by radiation, most recent progress in this field is directly traceable to some recent progress in atomic physics. Thus the recognition that the mean molecular weight of matter inside a star may approach a limit in the vicinity of 2 was suggested (by Newall and Jeans) as a direct consequence of the fact known from X-ray experiments that even the most strongly bound electrons may be knocked out of the atoms by suitable stimuli. Eddington's theory of 'white dwarfs' is based directly on the small dimensions of atoms in Kor L-states predicted by Bohr's theory. The theory of the stellar absorption coefficient, imperfect as it is, was based on recent measurements of X-ray absorption coefficients. When astronomical theory is still groping in the outermost darkness concerning the source of stellar energy, or the origin of the penetrating radiation discovered by Hess and Kolhorster, is it not ultimately because essential facts concerning possible transformations of matter are still out of touch with the technique of the physicists ? Eddington's book gives, of course, full recognition to the dependence of astrophysics on physics, and may, just for this reason, cause grief and humiliation to the classical astronomical reader who is out of touch with the modern trend of science in this field. The general run of the book is as follows. After a short survey of the main features of the problem, both from the observational and from the theoretical side, two chapters are devoted to basic physical theories concerning radiation, atomic structure, and the statistical theory of gaseous assemblies. The fifth and sixth chapters give a thorough discussion of the theory of hydrostatic equilibrium of gaseous stars. In the seventh chapter the theoretical formula connecting the total luminosity of a star with its mass, dimensions, and mean opacity (suitably defined) is calibrated by comparison with observations. The result is that the mean opacity is about constant for stars with the same mass, while it does vary for stars with different masses. The relation in question is, therefore, essentially one between luminosity and mass, the dimensions of the star being of no particular concern. The theory thus amplified is, in Chap. viii., applied to different problems concerned with variable stars. The pulsation theory of Cepheid variability is given in full, its odds and ends are looked into; and a similar theory of long-period variability is tentatively suggested.So far, the constancy and numerical value of the opacity appearing in the mass-luminosity relation has been used as an observational fact. In Chap. x. this question is taken up from the physical point of view, and it is shown how ionisation theory, coupled with almost any reasonable radiation theory, accounts satisfactorily for the observed constancy of the opacity in stars with the same mass as well as for variation with mass. The numerical value of the opacity predicted by theory seems, however, to be decidedly smaller than the observed one, a riddle which is left unsolved by the author. In the tenth chapter several accessory problems are considered, such as the exact degree of ionisation of stellar material, the validity of perfect gas laws., distribution of different elements throughout a star, and the problem of rotation. The discussion of the delicate question of the source of stellar energy is reserved for the last chapter in the series. There is no doubt that this problem is one of the most urgent in modern astronomy. It seems, however, that we still are remote from an adequate solution, and the author has therefore concentrated his attention on a thorough and open-minded discussion of suggested possibilities, and has not endorsed any hypothesis in particular. This chapter closes the book, as defined by its title. Two chapters on allied subjects are, however, added, one, on the theory of stellar spectra, and the other on the state of matter in interstellar space.The book will doubtless be heartily received, not only by astronomers, but also by physicists as well, many of whom are deeply interested in astronomical problems. It is stimulating reading; not only where one agrees, but also where one does not agree with Eddington. I feel myself in opposition as regards quite a number of (minor) points. Take, for example, the chapter on quantum theory. Here the requirement of reversibility of physical processes in a state of thermal equilibrium, which was established long before the advent of quantum conceptions, is raised to the rank of Law I. of quantum theory. In the same chapter a hardy attempt is made, on the basis of this Law I., to construct a new statistical technique, which evidently is intended to supersede ordinary statistical mechanics. Without passing any judgment as regards the failure or not of this attempt, I should much have preferred the use of ordinary statistics in a book intended for the general reader. The statement in 193 that radiation pressure acts primarily on atoms, not free electrons, seems to me to need further elucidation, especially in view of the statement made in 147, that "there can be little doubt that the principal process of absorption in the stars is the photo-electric effect." There are other places, too, where I doubt if the statements are adequate to the facts. Further, I have the impression that the book might have been easier and more straightforward reading if less attention were given to theories which might better have been left to a merciful oblivion. It is no use, however, to dally long over such questions. The book is undoubtedly destined to exercise a great and healthy influence on the scientific activity in this field; and nobody who reads it can fail to feel a deep admiration for the extraordinary flexibility of mind of its author, for his power of going to the root of difficult questions of the most diversified kinds, and for his remarkable ability of expounding his results in intelligible language.

ISSN:0028-0836    

DOI:10.1038/119111a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

FATHER HOFMAYR has produced the first 1F monograph on a tribe of the Anglo-Egyptian Sudan, and is therefore to be congratulated. Yet, grateful as ethnologists must be for this volume, the author has distinctly lessened the value of his monograph by limiting the material he has used. So far as the Shilluk themselves are concerned, he seems to have depended for the bulk of his material on the unfinished notes in the journal of the late Father Banholzer; it is true that he has supplemented these by a number of his own observations made between the years 1906 and 1916, as well as those of two other missionaries, Fathers Kohnen and Stang, and added some useful comparative material collected by Father Crazzlara among the Acholi, but he has not availed himself of the material which has appeared during the last few years in Sudan Notes and Records; indeed, the reviewer has not noticed any reference to this most useful periodical. These remarks are made in no carping spirit, but are necessary, for in an important work such as this it is advisable that the reader should realise the extent to which omissions are probable. There is no index; only a table of contents. This said, there can be little but praise for the work. The book is divided into four main parts, the first of which deals with the early wanderings of the ruling stock, and ends with their settlement in their present land under Nyakang-the founder of the Shilluk nation and the first king. Here the most important fact that is brought out is the former existence of a Jur-Shilluk tribe, the people of Dimo, who remained as Jur in their present country, while the adherents of his father's halfbrother, Nyakang, followed the latter in his migration. The second part might be called the Book of Royalty, since it treats of the dynasty founded by Nyakang, gives a genealogy of the royal family, examines the reign and chief doings of each king, describes the life of a king from birth, through youth, adolescence, maturity, to death and burial, and ends with a short account of the court language, i.e. the vocabulary, not a very copious one, applied especially to the king and his doings. A number of tables of succession are given, three collected by Europeans and four derived from natives; that accepted differs from those previously collected by Banholzer, C. G. Seligman, and Westermann. Chat is given as son and immediate successor of Nyakang, while a queen, Abudok, daughter of Boc (Bwotch), is admitted to the list of reigning sovereigns. This queen was unpopular, her judgment and awards being doubted on account of her sex, and her manner of death is unknown. There are other minor differences, and, considering the authority of Father Hofmayr's native informants, it seems that the list he compiles (p. 42) should be regarded as authoritative and be accepted in future, while the I queens' of whom the writer heard vaguely in the south can be accounted for as the princesses referred to as chiefs (p. 71). History is considered to begin with the fifth king, Ochalo (Ocwolo), about 1600, but no evidence is adduced for this date, which gives an average of about thirteen years for each reign.The life and activity of the Shilluk king is dealt with at length, many fresh details being given, but nothing that substantially contradicts earlier accounts. Thus the suggestion put forward by Seligman that the folklore account of the king having at one time to fight for his life actually refers to a former condition is supported by the sham fight, theoretically the first indication of his election, between the king-elect and one of the four 'high chiefs ' of the Shilluk country. At Debalo, the first village that the king-elect enters ceremonially, three fires-kindled by friction-are made in front of a large hut which is specially built for the occasion and where the king-elect should spend a month. One of these fires becomes the life-token fire of the new king, and a brand therefrom is carried to the capital-Fashoda. The description of the royal entry into the capital differs but little from that of previous authors. Father Hofmayr, however, has recorded an interesting addition; the king treads on an old man laid bound on the ground for the purpose. According to an account given to the reviewer in 1921, this was substantially a human sacrifice, for the old man was covered with flour paste, and was so betrodden by the multitude that he was expected to die. The king passes three days in a special hut, and then on the fourth day is carried by the Ororo to Aturwic, his home on the built-up mound at Fashoda; here a further period is spent in retirement. After this the king is for the first time acknowledged throughout the nation. On his first leaving the mound the king is engaged in a sham fight, in which he vanquishes his opponent, and the ceremony is brought to an end with a sacrifice. The chiefs make oration on the rights and duties of the ruler, emphasising their points by brandishing their spears and thrusting them into the ground. The king promises to be a just ruler, to punish wrong, and to protect the weak, and then dismisses the people with an exhortation to remain true to Nyakang and the ancient customs.A new fact with regard to the king's part in the rain ceremony is that as a last resource, after repeated failure, a man or boy might be sacrificed, and this might also be done for success in war. The third part of the volume, dealing with religion, begins with a most stimulating discussion of the meaning of the word Jwok (Juok), not only in Shilluk but also in those of the related languages sufficiently well known to permit comparison. So far as the Shilluk are concerned, Jwok is certainly the high-god, the creator, now but little concerned with mankind, but it is noted that disease might be spoken of as jwok, though (alternately) each disease has its own name, while in Shilluk folklore men endowed with super-normal powers may also be called Jwok; moreover, the actual practice of sacrifice to benefit a sick man suggests a closer connexion (on this occasion almost a synonymy) of Jwok and ancestral spirits. It may be added that certain spirits of the river and bush of considerable importance among the Acholi (who speak a simplified Shilluk dialect) are recognised by the Shilluk, though among these they have little importance.The account of Jwok is followed by that of the ajwogo (adjuago), the 'man of Jwok,' or the 'good medicine-man,' as he has been called, whose actions are, generally speaking, social and beneficent even if they clash with European ideas; it is the jalyat who is the 'witch,' the evil medicine-man who by his magic kills people for his own ends, or, more generally, incited thereto as the result of private enmity. The observations on totemism constitute an important addition to our knowledge. It should, however, be noted that the belief is less obvious, and, apart from exogamy, has less social importance, and is certainly less loaded with effect, than among such frankly totemistic tribes as the Dinka. The fourth section of the work, entitled " Country and People," contains a deal of heterogeneous information, much of which is new, e.g. the political divisions of the country, the greater part of the life-history of the individual (pre-natal to burial), technology, forms of salutations, oaths, stories, riddles, and a most valuable corpus of more than 100 songs, providing much material for future analysis. The book concludes with a number of plates and useful technological diagrams.

ISSN:0028-0836    

DOI:10.1038/119113a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

P4R. DE BEER has written an excellent little Al1 book. It is the first attempt in English to survey the field of experimental embryology since the publication of the late J. W. Jenkinson's " Lectures " in 1917, and in the interval much new work has been done. The author does not attempt to include an account of all this work; on the other hand, he has purposely selected from an extensive literature descriptions of those experiments which have a common bearing in elucidating the more essential problems. The consideration of the development and determination of the sexual characters has been deliberately excluded on the ground that this subject has been dealt with recently in works by Goldschmidt and Crew. This is perhaps to be regretted, since some of the best examples of the successful application of the experimental method might have been drawn from recent investigations in this branch of study, and many of them without encroaching on the subject matter of either of the two books referred to. It was inevitable, however, in a work of this size, that the author should select his material, and as it is, he has succeeded in covering a wide field. At the end of the volume is a tabulated list of the experiments cited, with due references to the authors and to the literature. Mr. de Beer begins by pointing out the relation between descriptive and experimental embryology; in so doing he might have added that the relation is essentially the same as that between descriptive and experimental physiology. Embryology, like descriptive physiology, differs from morphology in the introduction of the time factor; that is to say, it deals with sequences of events. The study of the processes of salivary secretion or the cestrous cycle can be undertaken without recourse to experiments (unless the killing of the animal at a particular stage of activity be held to involve an experiment) in just the same kind of way as the tracing of the progress of development. But it is only by the use of the experimental method that we can study the mechanism of the secretion and the nature of the stimulus which produces it, or the interaction of the ovaries and the other organs concerned in accounting for the cestrous cycle. The subject of this book, therefore, is the experimental physiology of the developing animal.After a chapter on fertilisation, in which Lillie's theory is duly set forth, the author proceeds to the consideration of parthenogenesis and the factors which activate the egg. The evidence from experiments on larval hybridisation is then separately discussed, and it is shown that the activating effect of the sperm can be distinguished from its hereditary effect. Sections follow on the relation between the sizes of nucleus and cytoplasm and the value of the chromosomes. Unlike a recent reviewer in NATURE (June 5, 1926, p. 781), the author adopts the view (in our opinion with justification) that the chromosomes are the bearers of the hereditary characters, and he points out further that experimental embryology provides evidence that each chromosome of the sets brought in by the nuclei of the sperm and ovum has a particular and essential part to play. The next four chapters are on cleavage, and the internal and external factors in development are then discussed. There are admirable summaries of the important work of Child on ' axial gradients' in the rate of metabolism of the tissues, and that of Spemann and others on differentiation and the reverse process of reduction. The latter occurs normally in the resorption of the amphibian tail, or abnormally by starvation, as with the planarian. The self-regulating power of the organism is discussed under the head of 'regeneration,' as well as in a later chapter. The action of hormones as factors in development is illustrated by the part played by the thyroid in amphibian metamorphosis, and it is shown that the 'all-or-none' law, which Lipschfitz has sought to apply to the working of another hormone, does not hold here. In the next chapter the author deals with the relation of nerve to muscle in embryonic growth. Finally, there is a brief review of development, in which certain general principles are discussed.The author does well to remind us that " with regard to the term 'explanation' . . . ultimately nothing can be really explained." He might have elucidated the matter further by saying that the term is used in science to denote the process of co-ordination of facts whereby these can be brought under general schemes or laws which enable us to generalise and to predict. A distinguished physicist is reported to have said that a law of Nature is not a statement of fact but of policy. The test of the soundness of the policy or the validity of the law is that the events we expect are the events which come about. The author of the book under review is not certain whether the processes that go on in the living organism can be satisfactorily interpreted on a physico-chemical basis or whether they may " require non-physical categories to contain them." It is clear that the conceptions he employs as to the self-regulating capacity belong to teleological categories, like those relating to 'compensatory hypertrophy' in the physiological text-books. The only test of the validity of such conceptions is whether they enable us to advance our science by generalisation and prediction. If they do this, they reflect recognisable degrees of reality.

ISSN:0028-0836    

DOI:10.1038/119114a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IT is fifty years since the first volume of Buckton's 1 monograph on British aphides was published. Since that time, plant lice have been widely studied in Europe and America, and more recently in Japan and other countries. Mr. Theobald has studied the aphides of Britain for some thirty years, and has published numerous papers on them from time to time. Every one interested in insects, particularly economic entomologists, will welcome, therefore, the publication of this up-to-date monograph, based on the author's extensive studies. The classification adopted follows closely that of Baker (1920), which is certainly the most rational and logical one in existence. It is proposed to deal only with the family Aphididce, and this first volume is concerned with the sub-tribes Macrosiphina and Pentalonina. Fourteen genera and 133 species are recognised, and in addition four other species are noted in the appendix. Descriptions of the parthenogenetic females of the species together with keys are given, the salient external features being figured. In addition, notes on synonymy, food plants, localities and biology are added. The sexuales are unknown in many species of aphides, and it is surprising that in only nineteen of the above species are both sexual forms described in this volume. In five other species the male only is described, and in five further cases the sexual female only is described. It is not clear whether we are to conclude that the sexuales are unknown in all the other species, or whether they are omitted in some cases because they do not require special notice. For example, on p. 216 the apterous oviparous female of Rs. ligustri is stated to be abundant, but it is not described. Similarly, on p. 14 the sexual female of C. rosarum is referred to, but no description of it is given under that species.A useful introductory chapter gives an account of the general morphological and biological features of the Aphididxe. The statement on p. 6: " The rostrum was formerly looked upon as the labium, but it is really an extension of the body," requires further explanation; the available embryological evidence indicates that the rostrum in Rhynchota is labial in origin. The old nomenclature for the wing veins is used. One feels it might have been better to have adopted the nomenclature of the Comstock and Needham system, as Patch has worked out the homologies in aphides. Two misprints not included in the errata have been noted: the genus Aphidiella should read Aphidella; the specific name M. scrojpularice should read scrophularice.Entomologists owe a great debt of gratitude to the author for the laborious task he has so faithfully carried through, and will look forward to the early publication of further volumes.

ISSN:0028-0836    

DOI:10.1038/119115a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

DR. J. H. BRIDGES was the most philosophic and scientific mind among the leaders of the positivist movement at the end of the last century, and it is good to know that he will at last be recalled to mind, while many who knew him in person are still alive. For he was unique in many ways, a most attractive and lovable character, above all a thoroughly typical Englishman who had succeeded in putting himself in the right European and international position without forfeiting a jot of his national qualities and attachment. He became, by his training at Oxford and as a doctor and by his attachment to Comte, the most all-round man of his time, specially interesting to readers of NATURE and contemporary men of science generally. After taking the ordinary course of 'Literae Humaniores' at Wadham, Dr. Bridges qualified himself thoroughly as a physician, and throughout his life kept the balance true between scientific and literary and historical studies. Had he not been preoccupied with the organisation of the Poor Law infirmaries of London, there can be no doubt but that he would have contributed largely to historical writing of the type now so much needed, namely, synthetic history, in which the due place of scientific thinking in building up the social structure is duly recognised and maintained. As it was, he wrote a number of valuable short studies, of which Mrs. Liveing gives a useful list. Apart from its success as a personal portrait, her book is well worth getting for its inimitable picture of the life in the evangelical parsonage where Bridges spent his youth, and to which he always turned back with affectionate memories in spite of his later developments. One must read the literal account of all this in Mrs. Liveing's authentic narrative before one can believe it, and it would be a pity to spoil the enjoyment of this or of the delightful figure of his mother by quoting any fragments. The whole is the best recent biography which has appeared, sympathetic, well-balanced, sufficiently detailed, and not too long. It gains much in value by the extremely interesting study of positivism and science by Prof. Patrick Geddes.

ISSN:0028-0836    

DOI:10.1038/119116a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

IT is with regret that one learns of the sudden death of the author of this book almost immediately after its publication. But though the author has passed away, his book remains, and sentimental considerations must not prevent a reviewer from giving a plain statement of his impression of it. The book is meant primarily to assist the beginner and to instil into him some enthusiasm for that most fascinating of hobbies, the study of pond life. In his desire to popularise this subject, the author has certainly written a very attractive and interesting book. He had considerable experience of the subject, and has therefore been able to give much valuable information on the habitat and the best method of collecting fresh-water organisms. Both animals and plants are treated very fully. Most of the illustrations are admirable, and there are a great many remarkably fine photo-micrographs, the majority of which are taken with dark-ground illumination. There is a useful glossary at the beginning of the book, and a really valuable chapter has been written by Mr. Chas. D. Soar on Hydracarina. Unfortunately, the book contains much that is both incorrect and unscientifically written. A list of a few such blemishes has been sent to the publishers.

ISSN:0028-0836    

DOI:10.1038/119117b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

As has been shown by the work of E. P. Lewis and of Strutt and Fowler, the spectrum of active nitrogen consists of three systems of bands (α, β, and γ bands of Strutt and Fowler), of which only the α bands (part of the first positive nitrogen bands) appear if oxygen is carefully excluded. The investigations of Lewis, and later those of Strutt, indicated that the γ bands (third positive nitrogen bands) and β bands are both due to the presence of small amounts of oxygen as nitric oxide. Dr. H. Sponer has recently shown (Sponer, NATURE, 117, p. 81, Jan. 16, 1926, and Sponer and Hopfield,Phys. Rev., 27, 640, 1926) that this is certainly true, and that the β and γ systems have a common final state which is the normal state of NO. This is in agreement with the calculations of Birge and of Mulliken, which indicated that, with a certain assignment of quantum numbers, the vibrational constants for the final state are identical in the two systems. In a recent paper in thePhilosophical Magazine(Sept. 1926, p. 621), Dr. R. C. Johnson and Mr. H. G. Jenkins give equations for the frequencies of the β system heads in terms of the vibrational quantum numbers. The proper assignment of quantum numbers was self-evident after the common final state of the β and γ bands had been recognised.The / bands were first observed by Lewis in 1899 while studying the nitrogen afterglow. These bands were later measured and arranged in Deslandres' progressions by Fowler and Strutt, using photographs obtained with a quartz spectrograph. We have now photographed the bands in the second order of the 21-foot concave grating at Harvard University, using as a source active nitrogen to which enough air had been added to quench completely the a bands. Practically all of the ,3 bands hitherto reported appear on our plates, and we have undertaken a comprehensive analysis of the system. It has recently been shown (cf. R. T. Birge, NATURE, Feb. 27, 1926; R. S. Mulliken, Phys. Rev., Nov. 1925 and Sept. 1926) that the electronic states of many molecules show a close parallelism to those of certain corresponding atoms. In particular, these analogies indicate that the NO molecule should have a doublet P (2P) normal state like the aluminium atom. Assuming that the y bands correspond to a 2S 2P transitioi in NO (cf. Mulliken, l.c., and Phys. Rev., Dec. 1926), the observed doublet separation AP of 122 wavenumber units for these bands should represent the separation between the 2P, and 2P, sub-levels of the 2P normal state. Now the /3 bands also show a double electronic frequency for which, according to our analysis, Am = 91 -05. Assuming identity of the final states of the d3 and -y bands, we may reasonably conclude that this AP represents the difference between an electronic doublet separation AP = 31 for the initial state of the [ bands and the separation AP = 122 of the final state. The relations just discussed are illustrated in Fig. 1 (the energy levels are not drawn to scale).FIe. 1. Each of the two heads, in each [ band, corresponds to a series of lines which constitutes a P and an R branch of the ordinary type, except that in the highfrequency sub-band two lines are missing in the otherwise continuous series, and four in the lowfrequency sub-band. Quantum analvsis shows that each complete band involves four distinct setsof rotational levels, two initial and two final, i.e. one set for each of the four electronic states above assumed. The analysis shows further that the rotational quantum numbers are integral in all four cases if the rotational terms are of the form B (j2 a2) + . . . The missing lines then correspond to the rotational transitions 0-1 and 1->-0 in the highfrequency, and to 0-ed, 1--0, 1->-2, and 2->-1 in the low-frequency bands. They are completely accounted for by a= (for both initial and final states) in the high-frequency and a = l in the lowfrequency sub-bands, since j is necessarily limited to values equal to or greater than a. Here ais an electronic quantum number; ah/27r is the resultant electronic angular momentum of the molecule, which is here directed along the internuclear axis. The high-frequency bands then correspond to a transition 2Po 2P1 and the low-frequency bands to a 2p 2p transition. This interpretation is completely in harmony with the generalisations of one of the writers (Mulliken, l.c.) in regard to j and a values, etc., in odd and even molecules. The above description requires slight modification in that the lines of the higher frequency bands are very close doublets, the separation of which is apparently proportional to j. They begin to be resolved, on our plates, at about j = 16, where the separation is 0 24 wave-number units. This shows that the rotational levels in one, or both, of the 2P1 states are double.Intensity relations among the band lines give strong support to the above interpretation. For the intensity I of any line, one expects I = ie E'/kT, where E' is the energy of the initial state, T the absolute temperature, and i a probability coefficient. The observed intensities of the P and R branches rise to a maximum and then fall, the distribution being almost completely symmetrical in the two branches, as in the CuH and HCl bands. For high j values, however, the P branch is somewhat the stronger, as would be expected due to the factor e-E'/kT. At first sight the bands appeared to contain only P and R branches, but on careful inspection a very weak Q branch was found in each band, with the intensity decreasing steadily from the first line. The Q branch is much weaker for the higher frequency (2p,) than for the lower frequency (2P,) bands. In the former the first line is fainter than the first lines in the P and R branches, but in the latter it is somewhat stronger. All the above intensity relations are in exact accord with the intensity formulae (for the i values in the equation above) deduced with the aid of the summation rule by Htnl and London (Zs. fulr Physik, vol. 33, p. 803, 1925) for the case where the electron transition involves no change in a. Even the particular values 2 and 1' for a are definitely justified by the observed intensities in the Q branches (according to Hdnl and London's equations the intensities of the Q lines should be approximately proportional to ff2J). Preliminary values for the moment of inertia and internuclear distance in NO have been calculated. In the initial states the latter has the values 1 44 x 10-8 and 1-40 x 10-8 cm., in the final (normal) states the values 1-16 x 10-8 and 1 14 x 10-8 cm. We have also found a difference in the vibration frequency for the two components of each doublet, which is evident from gradual changes in the frequency separation of the double bands. In the normal state it is about one part in 5000, and in the excited state somewhat larger and apparently in the opposite sense.From the data now available it will be possible to calculate exactly the specific heat and magnetic susceptibility of gaseous nitric oxide. Referring again to Fig. 1, we see the possibility of two other transitions, 2P2 to 2P. and 2p2 to 2P2, which, however, are completely absent from our photographs. Their absence and the presence of the other two transitions are in agreement with the new theory of Hund (Zs. fur Physik, vol. 36, p. 657, 1926). A complete account of our results will appear later, probably in the Physi

ISSN:0028-0836    

DOI:10.1038/119118b0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

AN account was recently given of some new mutations inGammarus chevreuxiSexton (NATURE, Feb. 6, 1926). A certain ‘white-body’ mutation did not behave in a simple Mendelian manner. In this mutant the body is devoid of the normal green and brown pigments. The mutant is recessive to the normal ‘black-eyed’ form, and the homozygote mutant has black eyes and white body (white-body Black). With certain exceptions to be considered later, ‘Whitebody’ is recessive to another mutant, the ‘New Red’ (with red eyes and normally pigmented body). But if homozygous for ‘White-body,’ the ‘Red’ fails not only to develop body-colour but also the red eye colour; a ‘White’ individual in both eyes and body results.That these 'Whites' do carry 'Red' can be seen by crossing them with normals, Reds appearing in F2. From this it is evident that a cross between 'White' and 'New Red' should by simple Mendelian principles yield in F1 either all Red-eyed individuals or 50 per cent. Red-eyed, 50 per cent. 'Whites,' according as the 'Red' individual was homoor heterozygous for the body-colour factor. This does occur when a ' White ' male is crossed with a ' New Red' female. But the offspring of a 'White' female and a 'New Red' male are always white. This is no question of sex-linkage, since both males and females homozygous for the 'White' mutation can be found. The F1 Whites are by no means all simple ' Whites.' Many of them belong to the class of 'changelings'; these are 'White' at birth, but take on the appearance of 'Reds' as life proceeds. Broods consist either of all 'changeling' or 50 per cent. Changeling to 50 per cent. true 'White' according as the Red male is pure, or is heterozygous for 'White.' Changelings can be obtained not only from 'White' mothers, but also from certain matings of ' White-body Black' mothers, if carrying New Red. The following conclusions have been invariablysubstantiated in the history of the stocks: (1) Changeling whites occur only where 'Reds' would be expected.(2) They always have a mother with a white body. (3) They always behave genetically simply as Reds, but(4) They are always heterozygous for 'whitebody.' This last conclusion follows from their maternal derivation, since a 'white-body' individual is always homozygous for that mutation. These facts seem impossible to fit into an ordinary Mendelian scheme, but the following considerations appear to provide a working hypothesis. Normal individuals possess a gene for 'body colour' which corresponds to the 'white-body' mutant gene. Individuals homozygous for the 'white-body' factor (whether 'White' or 'white-body Black') cannot lay down body pigment or red eye pigment. So long as its normal counterpart the 'body-colour' factor is present, the presence of the 'Red' factor ensures the manufacture of these pigments. We may therefore suppose the normal 'body colour' gene is concerned with the manufacture of some precursor from which pigment can be formed. In the 'white-body' mutant, failure to form the precursor consequently gives the 'Red' factor no precursor on which to act; a 'White' individual results.'White-body' females ('White' or 'white-body Black') are unable to lay down any precursor in the egg-cytoplasm; its abundance in the normal egg is testified by intense pigment formation in the ovaries. When, therefore, a white-body female is crossed with a 'New Red' (possessing the normal 'body-colour' factor) the F, embryo is at a disadvantage. It possesses the necessary factors to change precursor into pigment, but at first the precursor itself is absent. (The amount brought in by the cytoplasm of the sperm may be neglected.) The embryo certainly possesses the 'body-colour' factor introduced by the sperm, but this must make a store of precursor ab initio, and probably this cannot be done until feeding commences. In any case it will be long before the deficit is made good, and it is thus easy to see why the embryos are 'white' on hatching. But as feeding and growth proceed the precursor deficit will be gradually made good; pigment can be laid down and the animal can assume its true 'genetic ' appearance of 'Red.' In the converse cross, White male by Red female, the eggs have the normal amount of precursor>so that the genetically 'Red' embryos are at no disadvantage and can form pigment immediately in the normal manner. Further results may be predicted from this hypothesis. A 'Red' female forms eggs containing the precursor. If she carries 'white-body' and is mated with a male containing 'white-body,' some embryos will not possess the 'body-colour' factor and cannot therefore form the precursor. But the initial presence of a limited supply might allow the embryo to form pigment for a short time, though later it would be unable to do so. Consequently we might expect retrograde 'changelings' genetically 'white,' but starting with a faint colour which does not develop or is lost as life proceeds. Cases of this have been observed.Again, except for the possession of the black eye, the 'white-body Black' resembles a true 'White,' and its relation to 'Normal Black' is the same as the relation of 'White ' to 'Red.' Therefore 'whitebody Black' changelings should occur, which later develop into 'Normal Blacks' and behave genetically as such. These cases have also been found. The phenomena described above are of interest because they seem to present a clear case of the relation of the cytoplasm to Mendelian factors. It should be understood that no question of cytoplasmic inheritance is involved. The hypothesis outlined is simply a physiologically legitimate extension of the Mendelian theory. It may be illustrated by the not improbable supposition that the basis of the actual pigment of the body and the red pigment of the eye is some substance never formed by the animal itself but is of vegetable origin. In the normal egg sufficient of this basal substance (or precursor) is contained in the yolk to provide what is necessary for the body-colour and red eye-colour of the newly born animal, later supplies coming directly from the food. When the yolk of the egg contains no basal substance, the red eye colour and the body-colour are absent in the just-hatched young, though some or all of these young are genetically 'Red.' As they feed they obtain the necessary basal substance from their vegetable food, and by converting this into special pigments become normal red-eyed animals with full body-colour. These are the ' Changeling whites.' It ought to be possible to test this

ISSN:0028-0836    

DOI:10.1038/119119a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature

摘要:

THE paper by Messrs. Carpenter and Tamura in the November number of theProceedings of the Royal Society, on “The Formation of Twin Metallic Crystals,” presents a picture of the twin boundary which seems to me to be incorrect. The authors have assumed that the two halves of a twinned crystal are derived from each other by reflection in a plane which does not pass through atom-centres, but passes, in the case of face-centred cubic crystals, exactly half-way between two consecutive planes, through atom-centres, of the form {111}. This is improbable, because it requires, as its proponents themselves point out, abnormally small interatomic distances across the twinning plane, and correspondingly high local stresses, for which there is no experimental evidence. It seems much more reasonable to suppose that the two halves of the twinned crystal are reflections of each other in a {111} plane whichdoespass through atom-centres. This picture of the boundary involves no abnormal distance between any atom and its immediate neighbours. Experimentally observable relations between twins are, of course, the same on either hypothesis.Messrs. Carpenter and Tamura have been led, on the basis of their hypothesis, to conclude that in the diamond-like structures of silicon and germanium, twinning must involve even greater local distortions than those they have accepted as necessary in copper or nickel. If the view here advocated is the correct one, however, it appears that twins in silicon and germanium may have the relation of mirror-images in a common plane, through atom-centres, of the form 100X. This requires no abnormality in the least interatomic distances, and the twins can only be made one continuous crystal by rotation of either half through 900 about a normal to their common plane at a common atom-centre, or by a geometrically equivalent process. (In the case of twins on a {111} plane the corresponding rotation is through either 600 or 18

ISSN:0028-0836    

DOI:10.1038/119120a0

出版商:Nature Publishing Group    

年代:1927

数据来源: Nature