The Zoologist/4th series, vol 1 (1897)/Issue 674/Notices of New Books
NOTICES OF NEW BOOKS.
This is a very interesting volume on a question of transcendent interest to ornithologists, to whom the problem of the migration of birds is as difficult of solution as is that of mimicry by entomologists. Avine migration as treated by Mr. Dixon derives a freshness by the perfectly original—almost revolutionary—method by which it is sought to be explained. The old teachings as to the part played by the important factors of change of climate and scarcity of food, and the theory of Polar dispersal, are quite discarded, and the author's main contention is that "the grand centre of Life's dispersal across the globe is an equatorial one, and that, from those regions where the greatest stability of climate and the most favourable conditions for the development of animal and vegetable forms are to be found, Life in two grand streams has flowed towards the poles." Glacial epochs are considered as exterminating influences and not as dispersing agencies, and on their cessation the areas over which they have exercised their icy and lifeless sway are again colonized from Nature's headquarters in the equatorial regions. Then again the old theory of avine hibernation, so generally considered as belonging to the limbo of forgotten suggestions, is not only revived, but its scanty evidence also amply discussed, and the conclusion stated that—"Strange, nay almost incredible as avine hibernation is, however, it must always be remembered that the evidence against it is purely negative; and that, although it has not yet been sufficiently established to satisfy the sceptical science of to-day, it has never been refuted."
With all the painstaking investigation now being pursued on the subject of migration by enthusiastic ornithologists, the industrious tabulation of their facts, and the critical collocation to which these facts are subjected, we still feel that much remains unrecorded owing to the difficulties of observation. Mr. Dixon forcibly expresses the opinion that migration is largely "a nocturnal drama of the air," and that "a captive balloon floated above some spot where migration is notoriously prevalent, as for instance at Spurn Point on the Yorkshire coast, in the Wash, on the Sussex downs, or, better still, over Heligoland, fitted with a powerful electric search light and various meteorological instruments, would result in priceless information concerning the annual movements of birds is absolutely certain."
Mr. Dixon's hypothesis is that both the northern and southern regions receive their migrants from the equatorial belts, but that "no migratory bird normally crosses the tropics to breed or to winter, in either hemisphere"; and as subsequently expressed, "one set of individuals passing to the Arctic tundras, the other set to Antarctic breeding grounds—from an equatorial winter centre." To make the author's proposition clear, and to accentuate his argument, we must give another quotation:—"We may conclude that the migration of birds in autumn is neither due to a fall of temperature nor a failure of food, although to the casual observer this invariably appears to be the case; but is initiated by a nostalgic impulse to return to certain centres which are in the majority, if not in all, cases associated with that gregarious instinct which in most species is only subservient to reproduction, and in not a few others is equally as strongly developed, as is proved by so many migratory birds breeding in societies and displaying social tendencies right through the summer."
It will be thus seen that the volume is surcharged with new matter, that we fain hope will meet with the candid consideration of naturalists, though perhaps with small chance of general acceptance among ornithologists. In fact, our author almost anticipates "being 'handled without gloves' by some mud-and-torpor-despising bruiser critic for my heresy." This is surely unlikely, for the book is full of facts as well as suggestions, again proves how the new method of enquiry has invaded ornithology, and is written throughout with a felicity of language and sustained advocacy which affords every weapon for the theory except convincement, though this is all that can be expected in a general way when new views are first promulgated.
This third volume of the Cambridge Natural History—vols, iii. and v. having previously appeared—fully maintains the interest and character of the series. No fewer than seven contributors have assisted in the publication, which renders the task of an adequate notice somewhat difficult in our limited space.
"Flatworms and Mesozoa" have been entrusted to the pen of Mr. F.W. Gamble. Besides a fully biological treatment and a system of classification, the general zoological reader will find many of those natural history narratives to which the pages of this Journal are always open. We may instance as an example a reference to the Liver-fluke of the sheep, Distomum (Fasciola) hepaticum, which produces the disastrous disease liver-rot. This "has a distribution as wide as that of a small water-snail, Limnæa trancatula, the connection between the two being, as Thomas and Leuckart discovered, that this Snail is the intermediate host in which the earlier larval, sporocyst, and redia stages are passed through, and a vast number of immature flukes (Cercariæ) are developed. These leave the Snail and encyst upon grass, where they are eaten by the sheep. Over the whole of Europe, Northern Asia, Abyssinia, and North Africa, the Canaries, and the Faroes, the Fluke and the Snail are known to occur, and recently the former has been found in Australia and the Sandwich Islands, where a Snail, apparently a variety of Limnæa truncatula, is also found."
The Nemertines are treated by Miss L. Sheldon. These worms are common on the British coasts, and about forty species have been recorded from this area. They "are often very diversely and brilliantly coloured, the hues most commonly found being white, yellow, green, deep purple, and various shades of red and pink." There are also land and freshwater forms, in the last of which there are certainly many new genera and species to be discovered. Altogether a zoologist in want of a speciality might well take up the Nemertine worms, and he will find Miss Sheldon an excellent "coach."
Mr. A.E. Shipley, one of the editors of the Series, writes on "Threadworms and Sagitta." If these little animals are not the most interesting objects of study to the general zoologist, they are at least not unimportant to man and his surroundings. Minute Nematodes abound in moist soil around the roots of plants, &c. In animal parasites we have the round worm, Ascaris lumbricoides, which inhabits the alimentary canal of man; A. mystax, found in the cat and dog, and A. megalocephala in the horse and ox. Parasitic in plants, they cause the formation of galls and other pathological growths; while the "Vinegar Eel," Anguillula aceti, "which occurs so often in weak vinegar, is another familiar example of this group." No fewer than "twenty-two species have been described as parasitic in man," and hence the cui bono which has often irritated so many amiable naturalists can scarcely be applied with effect to the specialist who investigates the life-histories of these unbidden guests.
Rotifers are under the charge of Mr. Marcus Hartog. These microscopic animals always recall to the mind of the writer that, in conjunction with Hudson, his old correspondent, P.H. Gosse, so aptly designated by Charles Kingsley as "that most pious and most learned naturalist," passed the last years of a long zoological vigil in their Monograph. Gosse was undoubtedly a true zoologist, but there is a danger lest he be principally remembered as the author of that bizarre publication 'Omphalos.' Mr. Hartog bears witness to the value of the 'Monograph,' and may be said to supplement it by giving the true biological details of the group. It is surprising how many interesting details may be studied in the life-histories of Rotifers. "Almost any organic infusions freely exposed to the open air will yield Ploima shortly after the active putrefaction is completed. The finer water weeds yield most of the beautiful tubicolous forms. A whole group of species and genera are quasi-pelagic in fresh and salt water, constituting a large proportion of the 'plankton' or floating life near the surface; and some of them are found in deep water, or in the depths of the lakes." Others again are parasitic.
Mr. W. Blaxland Benham has contributed a very useful treatise on the Polychaet worms. Most marine anglers are acquainted with that well-known and common bait the Lug-worm, Arenicola marina, amongst other Polychaet lures, which form part of the group of "marine worms, whose bodies are usually elongated and cylindrical; they either lead a free life swimming in the open sea or crawling along the bottom, or they pass their life in burrows or definite tubes of various kinds." Amongst other peculiarities, some species are polymorphic. "Claparède was the first to show that Nereis dumerilii may occur in at least five different mature forms; these differ from one another in size, colour, mode of life, character of the eggs, &c." Fission and gemmation and the regeneration of lost parts are not the least uninteresting details of these in general beautifully-coloured worms, which vie in hue with butterflies, but whose tints are far more difficult to preserve.
Earthworms and Leeches have become so associated with the name of Mr. Beddard, and his 'Monograph of Oligochæta' is so widely known and generally consulted, that we might perhaps confine our remarks by saying that this portion of the volume is from his pen, and those of our readers who have recently read the "Earthworm Studies" which are appearing in our pages, will do well to consult this memoir also. The classification of Leeches is evidently attended with some difficulty. As no fewer than sixty-four colour varieties of the common Hirudo medicinalis are said to exist, "it is not wonderful that the labours of some systematists have been severe, and have provoked much criticism and alteration on the part of others." We are not therefore surprised at the remark of Sir J. Dalyell, which is quoted in a footnote: "It does not appear that the history of the Leech has advanced in proportion to the number of literati who have rendered it the subject of discussion."
Mr. Shipley has also written the account of "Gephyrea and Phoronis." The Gephyrea are exclusively marine, and have been the subject of considerable taxonomic discussion. They were formerly associated with the Echinodermata; Lamarck placed them near the Holothurians; and Cuvier "also assigned them a position amongst the Echinoderms." Quatrefages regarded these animals "as bridging the gulf between the Worms and the Echinoderms." The Sipunculids have a diet which seems to consist almost entirely of sand, and, as Mr. Shipley observes, "The enormous amount of sand and mud which passes through the bodies of the Sipunculids shows that they must take a considerable part in modifying the mineral substances which form the bottom of the sea. Just as Earthworms, as shown by Darwin, play a considerable rôle in the formation of soil, so must these animals, in conjunction with Echinids and Holothurians, effect considerable modifications in the sand and mud which pass through their bodies."
The concluding section is devoted to the Polyzoa, and is from the pen of Mr. S.F. Harmer. The Polyzoa may be said to have existed without a history till the beginning of the present century. "Originally passed over as seaweeds, their real nature was established in connection with the discovery of the animal nature of corals." Even now the echoes of the controversy which raged as to whether Thompson's name of Polyzoa or Ehrenberg's term Bryozoa should be used are sometimes faintly perceptible. The first is employed by the majority of English writers, while the second is almost universally used by all continental authors. Many of the marine forms have a very wide distribution, Mr. Hincks having described several species as occurring from Norway to New Zealand. We are glad to see that Mr. Harmer still describes Mr. Hincks's 'History of the British Marine Polyzoa' as "invaluable," and his excellent contribution will, we feel sure, if studied, lead many more zoologists to study these somewhat neglected creatures, who are undoubtedly as interesting as "birds, beasts, or fishes."
In conclusion, we can only generally praise a most welcome addition to zoological literature, a volume we do not value because it only contains what is new, or is without any views that may be controverted, but because it affords the life-histories of animals whose study and observation are little in vogue, while the information is imparted by specialists who have pursued the modern biological method.
This is a worthy supplement to our own 'Zoological Record,' and all naturalists who seek to study the mysteries of the life, as well as the form, habits, and distribution of species will place the volumes of this series by the side of those we have mentioned, and which we so well thumb. 'L'Année Biologique' is under the general direction of Prof. Yves Delage, assisted by a strong staff, amongst the names of whom we notice enrolled our own countrymen, G. Mann of Oxford, J.A. Thomson of Edinburgh, and B. Windle of Birmingham. Each reference is in the form of a lengthy abstract and signed by its compiler, and the whole subject is distributed under sections which bear the names of the familiar studies which are now reconstituting the aims of Zoology. As we glance through these resumes of thought and work going on as it were beneath the surface of our own arena, the question arises whether we do not now only constitute the remnant of the "Old Guard," and that the Zoology of the future will be an edifice of which our hardly wrought bricks will form but the foundation. We welcome the appearance of the first volume of this excellent contribution to a knowledge of current Biology, and trust the work may annually increase its usefulness.
Zoology, once a playmate for the curious, a reference for the collector, and the strength of a popular museum, is fast becoming one of the most serious of sciences. The anatomy and physiology of animals is too often neglected; in fact, one sometimes remembers the jest made by Edward Forbes and related by Huxley, to the effect that the pure systematic zoologist was unaware that the stuffed skins he named and arranged ever had contained anything but straw. It is perhaps better, however, that we have specialists who devote themselves to each branch of our study, while our pages still remain that "home for destitute truth" relating to the natural history of living animals.
The Nemertine worms (Nemertinea) are described by Prof. Louis Joubin. In writing the word "described" we are not referring to specific diagnosis, but to the description of the worms themselves, their exterior characteristics, anatomy, physiology, and life-history. The principles of their zoological classification are well set out, followed by an "Index bibliographique" and a very full general index. The illustrations are numerous and, we may add, excellent, and, with the recent contribution on the same subject in the Cambridge Natural History, we feel that these lowly organized creatures are at length receiving adequate treatment.
Dr. Paul Pelseneer, in his necessarily larger contribution on the Mollusca, has pursued a similar treatment of his subject, which he has divided into the sections Amphineura, Gastropoda Scaphopoda, Lamellibranchia, and Cephalopoda. It has often been asserted that there were conchologists who devoted their whole study to the outside covering or shell of the species which they collected, and should such specialists find time or inclination to investigate the nature of the living animal itself, Dr. Pelseneer will at least prove a not inefficient guide.
Taxidermy, in some form or other, if not an ancient art, was at least an early practice. Besides the Egyptian mode of embalming to which Mr. Browne refers, we are told by Gibbon, that according "to the voice of history," on the death of the Roman Valerian, Sapor's illustrious prisoner, "his skin, stuffed with straw, and formed into the likeness of a human figure, was preserved for ages in the most celebrated temple of Persia." Animal effigies, for they could be called by no other name, must have had considerable influence in inculcating an early knowledge of Zoology, as well as the living wild animals imported for the purposes of imperial holidays. A Zoology without the practice of Taxidermy or animal preservation, is the science independent of museums and private collections, and valuable as field observations are, and recorded perhaps nowhere with greater alacrity than in the pages of this Journal, students still require both the living and the dead. Moreover, the love of Zoology is not always combined with the qualifications of Midas, and a knowledge of the art is necessary for the collector with a moderate income at home, as well as for the travelling naturalist abroad. Taxidermy is now an art, a thing of joy to the naturalist as he examines those beautiful cases of British Birds in our National Collection, and many who can spare the cash and not the time or energy, will gladly rely on professional assistance. As our author remarks, there is really no reason for "the narrow way in which most professional taxidermists bolster up their art in a secret and entirely unnecessary manner—unnecessary because no amateur can, but by the severest application, possibly compete with the experience of the technical or professional worker."
We cannot pretend to criticise a book which demands a special and technical knowledge. Mr. Browne is an advocate of non-arsenical preservatives, which perhaps prejudice alone may have prevented our having personally used. There are also to be found the recipes for numerous preservative fluids both for fish and reptiles, some well known and others apparently novel. Besides these, we are told how to fight and overcome museum pests, the material with which to mend broken specimens, how to clean skins and prepare microscopic objects, and to fit up cases and cabinets; of course the directions to skin and set up mammals, birds, reptiles, fishes, &c, are fully detailed, and the volume concludes with advice on museum arrangement. We have found so many useful hints in the perusal of this manual that we now regard it as a friend on the book-shelf to be often consulted, for there are few zoologists who are not collectors, and few collections that do not sometimes give anxiety. This is a subject which might well find a place in our "Notes and Queries."