of nature might be merged into the spacial relations. The five succeeding chapters discuss some of the consequences of the theory and their experimental investigation. The twelfth and final chapter gives some of the author's speculations upon the nature of things which seem to be summed up in the concluding paragraph which reads: "We have found a strange foot-print on the shores of the unknown. We have devised profound theories one after the other to account for its origin. At last we have succeeded in reconstructing the creature that made the foot-print. And Lo! it is our own.” The book will give the reader a good idea of the Einstein theory and how it has led to the prediction of three exceedingly minute quantities, namely, the secular motion of the perihelion of Mercury, the deviation of ray of light passing close to the sun, and the change in frequency of radiation in an intense gravitational field, for all of which evidence is now supposed to have been found. On the other hand the book seems, at least to one reader, too dogmatic in its presumption that the physical world is but the stuff of our consciousness and that physical phenomena are due to the oddities of space. The attitude of the physicist in general is a little more tolerant. He is content to specify such postulates or abstractions from the complex world of reality as are sufficient for the set of problems in hand and later if experiment shows that these are too limited he is frankly willing to extend them. For example, the ordinary problems of hydrodynamies are well enough discussed on the assumption of a continuum, but he does not feel that he must be held to this assumption when treating of the chemical properties of water or of the radiations from the hydrogen atom. Similarly if it should appear that time does not run on at a uniform rate, or that it is desirable to assume that it is discrete in structure; possessing something like the quantum in energy, doubtless the physicist will be ready to adopt the new hypothesis, only he will insist that it corresponds to something real in nature. While there is no doubt that the interlacing of space and time into a differential quadratic affords a valuable technique for the solution of problems in electrodynamics, the question whether a whole philosophy of nature based on an absolute velocity, as of light, will win universal acceptance, must still be considered an open one. The reader who may care for a more open-minded discussion of the subject will be interested to read the article on Gravitation and Light by Sir Joseph Larmor in the Proceedings of the Cambridge Philosophical Society. 19, 324, 1920. F. E. B. 9. The Principle of Relativity: by H. WILDON CARR. Pp. vii, 163. London, 1920 (Macmillan and Co.).-This little book on the philosophical aspects of relativity is the outcome of a course of lectures on "Historical Theories of Space, Time and Movement" delivered by the author at Kings College last year. The major portion of the book is taken up with a discussion of the speculations of the metaphysicians on the meaning of movement from the days of Zeno and Aristotle down to recent times. Although the author's treatment is historical in the main, he fails to give Lorentz and Larmor the great credit which they deserve for the theoretical development whose only logical outcome was Einstein's principle of relativity. The author has a chapter entitled "In what Sense is the Universe Infinite," but he does not mention Einstein's and De Sitter's interesting speculations on a re-entrant universe. The book is of more interest to professional philosophers than to physicists or mathematicians. II. GEOLOGY. L. P. 1. Zur Älteren Geschichte des Diskontinuitätsproblems in der Biogeographie; by NILS von HOFSTEN. Zoolog. Annalen, 7, 197353, 1916.-This essay on the theories of the variable distribution of plants and animals is limited to the living world, and does not consider the life of the past ages. The presentation is clearly and interestingly written by a biologist along historical lines. It begins with the theories of the Greeks as set forth by Hippocrates and Aristotle, who thought the distribution to be due to differences in the local climates, and follows the more essential ideas down to the present time. For a while the church stimulated this research because of the riddle of the wide distribution and variability of man, but in the end it fought the conclusions of the naturalists. Modern views began with the discovery of America, with its plants and animals which are different from those of Europe. Some continued to explain this difference by special local creations, and in fact Louis Agassiz (1850-1859) held to the creation theory to the end of his life. Buffon (1749-1756) is sometimes regarded as the originator of modern views in regard to biogeography. The way was further indicated by Cuvier (1815), Lyell (1830-1833), Heer (1845), and Forbes (1846), and modernized by Hooker, De Candolle, Darwin, and Wallace. Now we know that the organisms are where they are because of local genetic developments out of antecedent stocks, conditioned by their variable dispersion and evolution along varying routes of travel and climate, and that this variation was brought about in the main by the geologic changes in the configuration of the land surfaces and their oceanic boundaries. C. S. 2. Recent Molluscs of the Gulf of Mexico and Pleistocene and Pliocene Species from the Gulf States. Part I: Pelecypoda; by CARLOTTA J. MAURY. Bull. Amer. Paleontology, vol. 8, No. 34, 113 pp., 1 pl., 1920.-This is an annotated bibliography, with synonyms, of 345 forms of pelecypods, as limited by the title, along with their distribution and occurrence in the Gulf coast area. Only one new species is described. C. S. 3. Brachiopoda Triadica; by C. DIENER. Fossilium Catalogus, 1: Animalia, Pars 10, pp. 109, Berlin (W. Junk), 1920.This catalogue cites the bibliography of all the known Triassic brachiopods, which are divided as follows: Inarticulata, 3 genera, 26 species; Strophomenacea, 2 genera, 10 species; Spiriferacea, 12 genera, 260 species; Rhynchonellacea, 5 genera, 184 species; Terebratulacea, 8 genera, 146 species; total, 30 genera, 626 species. Five-sixths of the forms are restricted to the alpinemediterranean province; 19 occur in Germany, 77 in the Himalayan area, 14 are boreal, and only 4 andine. C. S. 4. Cephalopoda Dibranchiata; by E. v. BÜLOW-TRUMMER. Fossilium Catalogus, 1: Animalia, Pars 11, pp. 313, Berlin (W. Junk), 1920.-In this work is brought together all the literature treating of the fossil dibranchiate cephalopods. It has taken the author more than two years to prepare the manuscript, and all paleontologists should be thankful that the work has been done once for always. Thirteen genera are restricted to the Cenozoic, and fifty-eight to the Mesozoic. C. S. 5. Coal in Great Britain; by WALCOTT GIBSON. Pp. viii, 311, 8 pls., 50 text figs. London (Edward Arnold), 1920.-The author, after thirty years' experience in the coal fields, presents here a condensed but readable account of the geology of the coal of the late Paleozoic formations, mainly for mining engineers, mine owners, and mining students of Great Britain. The book should be interesting, however, to mining geologists in other countries. The first eight chapters are introductory to the geology of coal, and describe the nature, formation, origin, distribution, and something of the included fossils as zonal indices, together with chapters on prospecting and boring and on the stratigraphy of the exposed and concealed coal fields. The remaining fifteen chapters treat of the widely distributed coal fields of England, Wales, Scotland, and Ireland. "The distribution of coal according to quantity has been estimated for each continent, and is as follows in millions of tons: Europe, 789,090; Asia, 1,279,586; Oceania, 170,408; Africa, 57,839; America, 5,111,528. According to the class of coal, the world's estimated supply of anthracite coal is 496,846; of bituminous coal, 3,902,944; of sub-bituminous and brown coal, 7,397,553 millions of tons. In these estimates no allowance has been made for coal not mineable or for loss in mining" (p. 32). C. S. 6. A Monograph of the British Ordovician and Silurian Bellerophontacea, Part I; by F. R. COWPER REED. Palæontographical Soc., pp. 1-48, pls. 1-8, 1920.-In this interesting but uncompleted study of British Bellerophon-like gastropods are described and illustrated the species of the following genera: Sinuites (syn. Protowarthia), 15 forms (9 new); Sinuitopsis, 1 n. sp.; Oxydiscus, 5(2); Cyrtolites, 5(4); Isospira, 1 n. sp.; Bucaniella, 2(1); Bucania, 4(3); Kokenospira, 10(7); Tetranota, 4(3); Conradella, 4(3); Temnodiscus, 2 n. spp. The author arranges the genera in three groups: (1) Integridorsata (without median slit, band, or row of perforations; (2) Fissidorsata (with fissure); and (3) Terebridorsata (with median perforations). C. S. 7. West Virginia Geological Survey; I. C. WHITE, State Geologist. Another of the valuable detailed County reports of the West Virginia Geological Survey has appeared. This is devoted to Webster County and the author is DAVID B. REGER. It embraces xiv, 671 pages with 35 plates and 24 text figures. There is also a series of topographic and geologic maps in a separate case. Webster County contains the northwest extension of the famous New River Coal Group, as also the Kanawha Group and the lower members of the Allegheny Series in its northern portion. The price, including case of maps, delivery charges paid by the Survey, is $3.00; in combination with other volumes of the Survey, a special rate is made. Extra copies of topographic map cost 75 cents; of the geologic map, $1.00. The Survey may be addressed at Morgantown, W. Va. (P. O. Box 848.) III. ZOOLOGY AND BOTANY. 1. Sanitary Entomology: The Entomology of Disease, Hygiene, and Sanitation; edited by WILLIAM DWIGHT PIERCE. Pp. xxvi, 518, with 28 plates and 88 text-figures. Boston, 1921 (Richard G. Badger; price $10).-Just at this time, when there is such fear that the insect-borne diseases now raging in central and eastern Europe may become established in America, this untechnical treatise on the relations of insects and disease in all parts of the world is most opportune. The book is the outcome of a series of studies prepared by ten specialists for the training of a large number of people for any service which might be required in combating disease-carrying insects during the war. This information is of no less importance, however, in the prevention of disease now that peace between so many of the nations has been officially declared, for the louse and other insects continue their daily additions to the millions of deaths for which they have been responsible during the past few years. The treatment of the subject is entirely untechnical, so that any intelligent person, without previous knowledge of biology, can learn the essential facts about the various ways in which insects transmit the germs of diseases both to man and domesticated animals and the practical methods by which these diseases can be prevented or eradicated. The control of all kinds of insect pests in dwellings, farm-yards, packing houses and communities is also given in detail, with recipes for remedial treatment. The book includes not only the insects but also the mites and ticks, for the latter rival the insects in the transmission of diseases of domesticated animals, as well as by causing injuries by AM. JOUR. SCI.-FIFTH SERIES, VOL. I, No 5.-MAY, 1921. their parasitic habits. Simple directions are given for distinguishing the injurious from the harmless species of the various groups, for the protection of man and each of his domesticated animals from the former, and for the treatment of persons or animals suffering from these parasites. The book will not only serve as a guide to the study of insects in relation to disease, but it is the most useful handbook available for the sanitary officer, health inspector, nurse, and physician in their professional duties. W. R. C. 2. Embryology of the Chick; by BRADLEY M. PATTEN. Pp. ix, 167, with 182 figures.-Philadelphia, 1920 (P. Blakiston's Son and Co.). This little book consists of an untechnical description of the development of the chick during the first four days of incubation, during which period the principal organ-systems of the body are established. As it is designed particularly for the beginner in the study of embryology, all unessential details have been omitted and the discussion limited to the fundamental processes involved. The well-executed and fully labelled diagrams make as easy as possible the student's path through one of the most difficult, although one of the most fascinating, fields of biology. W. R. C. 3. University of Iowa Studies in Natural History: The Barbados-Antigua Erpedition; by C. C. NUTTING. Pp. 274, with 50 plates. Iowa City, 1919 (published by the University).-This is a delightful narrative of a collecting trip to the West Indies by a party of teachers and advanced students from the zoological department of the University of Iowa. The work of the party from day to day and the discoveries of strange forms of marine life which were made, as well as descriptions of the islands themselves, their natural resources, and the life of their human inhabitants, are recorded in a vivid style which bears witness not only to the enthusiasm and skill of the author but also to the charms of these wonderful tropical islands. In addition to the delightful story of the expedition, the book is a real contribution to science, for there are several chapters of zoological notes, recording obser vations on the habits of the terrestrial and marine animals of the region. W. R. C. 4. The Origin and Development of the Nervous System from a Physiological Viewpoint; by CHARLES MANNING CHILD. Pp. xvii, 296, with 70 text-figures. Chicago, 1921 (The University of Chicago Press).-The author here applies to the development of the nervous system his theory of axial gradients of susceptibility. He shows that both the protoplasm and the organism exhibit an "organismic pattern" of physiological gradients, the evolutionary development of which leads in the higher animals to the complex excitation-transmission relations of the nervous system; that is, "from the simple physiological gradient to the ego." With the support of extensive experimental evidence and a consideration of all groups of organisms |