Tim Natural-HistorySciences havefor some years past been attract- ing upon
themselves'an increasing amount of public attention, and w.; observe that they have, as branches either of instruction or am asement, established themselves recently within several of our larger schools. Lord Ellenborough, who from his place in the House of Lords protested against these, as he has often against other studies, may console himself with the consideration that the young ensign or cornet who may have been a member of the natural- history society of the school to which he belonged, will have gained thereby tastes and pursuits which will enable him, when at remote country stations in the United Kingdom, to live independently of the excitements of the small county town, and when on the sugar island in the tropics to dispense with the highly brandied hospi- talities of the resident planter. It is indeed open to question, whether the natural-history, as opposed to the natural, sciences have, as far as mere schoolboys are concerned, any much higher functions than those we have indicated. Most of them are in their very nature applied sciences, and for a fundamental knowledge of them a knowledge of several other primary sciences is required. And whilst in the results of their study they do not admit of the exact testing and estimating to which all boys' work ought to be subjected, the processes which have to be employed in the pursuit of them are liable occasionally to prove a little antagonistic to the maintenance of disciplinal routine. Chemistry and the mechani- cal sciences do admit of precision as to processes, and of accuracy as to estimation of results, and they may serve therefore as useful gymnastics for minds which are unsusceptible of culture through the medium of the new Latin Primer. Botany also, so far as it is systematic and classificatory, does admit of very considerable pre- cision and accuracy, even as a school study ; and as it may be made to call forth very considerablb activity in the way of verifi- cation and observation, and may easily be kept from degenerat- ing into anything like birds-nesting or butterfly-catching, it may, though a natural-history science, serve at school for uses to which zoology and physiology are more or less unfitted. But however Lord Ellenborough and ourselves may differ or agree as to the usefulness of these studies virginibus puerisque, it will be allowed on all hands that adults at all events pay attention to these subjects in much larger numbers nowadays than they did in times when the achromatic microscope was not yet invented, and the Origin of Species not yet written. And it is with express reference to the needs and requirements of individuals who are come to years of discretion, that we propose herewith to notice the two volumes on the Comparative Anatomy of Vertebrates which have been recently published by Professor Owen.
The author, in the opening sentences of his preface, refers to his single volume on the Comparative Anatomy of the Invertebrata as • Comparative Anatomy and Physiology of Vertebrates. By &chard 0 wen, F.5.5. 2 vols. Loudon: Longman'. 1866. forming part of the whole of which the two volumes before us will form, as we suppose, onetalf, and to which a fourth volume, con- taining the anatomy of the soft parts of mammals, will yet have to be added. And the four volumes, when completed, are to be considered as "completing the outline of the organization of the animal kingdom." An allotment, we must observe, which assigns but one out of four volumes which are to give an outline of the Invertebrate and Vertebrate worlds both, to the former of those two kingdoms, seems to us to be justifiable neither from the point of view which the man of science, nor from that which the dilet- tante would take. Both in modern and in geological times, both in space and in time, the Invertebrata outnumber and outweigh the Vertebrata ; and this their superiority in variety and number, both of types and of individuals, is ordinarily as distinctly repre- sented in the Handbook of Comparative Anatomy and the cabinet& of the virtuoso, as it is in the "Great Stone Book of Nature." As, however, the single volume on this multifold kingdom appeared now more than ten years ago, we shall not dwell any further on this disproportion, but shall direct our attention to the two. volumes before us, which treat of the Vertebrata, and endeavour to give our readers an adequate idea, firstly, of their general scope and bearing, and, secondly, of the position which their author has- taken up in them on certain special points to which more or less public attention has lately been drawn.
The first of these two volumes treats of fish and the other cold- blooded Vertebrata, the second is divided nearly equally between descriptions of all the various systems in birds and of the osseous systems of mammals These two later classes are ranged together,. confessedly Vol. L, p. 7, for purposes of convenience, as warm- blooded or htematothermal animals, in antithesis to the assemblage treated of in the first volume, and styled, in a somewhat strangely derived Grecism, hmmatocryal. The anatomyof these several classes is given under certain heads, chosen by reference to the several functions of life, animal and organic, the motor and nervous systems being in every case treated of first, and being followed by those of. organic or vegetative life. Two chapters on the development of the cold-blooded class and of birds justify the title, Comparative- Anatomy and Physiology of Vertebrates, which is printed on the back, though not on the title-page of each volume. Of physiology, however, as opposed to anatomy, of functions as opposed to- structures, we have not much in these volumes beyond what these two chapters and those on the active and passive organs of motion. convey to us. The great mass of the work is made up of disquisi- tions on pure anatomy, and is intended either to show forth the unity of type in structures, or the affinities and relationships of. different classes of animals. An instance, however, of a happy com- bination of all these several lines of investigation is furbished to. us in the following passage, which reproduces for us strikingly and convincingly the life and habits of the huge and now extinct Ground-Sloths of South America. At p. 413, Vol. II., we read as. follows :— " The principle of viewing structures and instruments in reference, to the work that they may do, is shown to be good in gaining insight into the mode of life of extinct animals in a striking degree through Re- application to the skeletons of the megatherioids. The teeth of these conform so closely in all characters with those of the sloths as to suggest leaves rather than roots to have been their food. In the light slender sloths the modifications of structure for climbing, clinging, and living altogether in trees are carried out to an extreme. In the colossal extinot kinds the foliage was obtained in a different way. The huge single claw on the hind foot would be applicable as a pickaxe to clear away the soil from between the ramifications of the roots, a second claw would have
interfered with such work A tree being prostrated, and its foliage thus brought within reach, every indication in the skull of the size, strength, flexibility, and prehensile power of the tongue harmonizes both the foregoing teleological conclusions. The megatherioids, like the
giraffe, thus plucked off the foliage on which they fed. It needed only evidence of the occasional occurrence of what might happen to a beast in the fall of a tree which it had uprooted to seal the fore- going physiological inferences with the stamp of truth, and the skeleton of the Mylodon in the Hanterian Muse= shows that evidence above the right orbit and at the back part of the cranium."
An equally happy and fruitful application of the facts of struc- ture to the elucidation of function is to be seen in Vol. L, p. 287„ where from a detailed comparison of those varying quantities, viz., the size of the cerebellum, the muscular activity, and the so- called " philoprogenitivenes.s in the class Fishes," the hypothesis which assigns the co-ordination of muscular movement to the cerebellum is shown, as clearly as "the method of concomitant variations" can show anything, to be preferable to the phreno- logical doctrine which "located amativeness" in the back part of the skull and brain.
Dismissing now from consideration the physiological, which is the least important aspect of the work before us, we will proceed to speak of its merits as a treatise on zoological and morphological, anatomy. And from the purely literary, or rather from the biblio- graphical, point of view, we think we have some reason to complain of the exceedingly large proportion of these volumes which matter already in one form or another published makes up. It is true that, with the exception of some eighteen pages on the vascular system of birds excerpted, overtly of course, from an ancient Cyclopseffia, Professor Owen has employed his scissors almost or quite exclusively upon his own memoirs published in the Transac- tions of various scientific societies and elsewhere. But a work of such detail of descriptive anatomy as the one before us must be unintelligible to almost every reader except within the precincts of a museum, where access can be had to actual specimens ; and within such institutions the original memoirs in question would ordinarily be accessible also, and would thus make supererogatory much of the letter-press contained in these covers. The force of this somewhat invidious objection is weakened, it is true, by the fact that these volumes are most richly illustrated, and contain more than 850 woodcuts. Still, teachers, and much more learners, of anatomy know that the exertion which is necessary for the comprehension through the medium of illustrations of even a single monograph of a rare specimen or animal is exceedingly great, and far more than an ordinary mortal can put forth and sustain through the successive chapters of a systematic work. Actual inspection of actual specimens is as necessary for most men in the mastering of their anatomy, as contact with the actual earth was to Antmus in his struggle with Hercules. We are sure that it is unwise to strive to compress the details of monographs Within the compass of a systematic work, and it is all but equally clear to us that it is impracticable to meet in the same volume the needs alike of the zootomist or anatomist and bf the inquirer into the morphological relations of the different forms and structures of living creatures. The two subjects should be treated of separately. Stanniurs and Wagner, the latter of whom may be judged of in an English translation, have shown that it is possible to treat of the zootomy of the Vertebrata, if not exhaustively, still most com- prehensively and availably, within the limits of a single octavo ; and Mr. Huxley, in his recently published Lectures on the Element of Comparative Anatomy, has given us a bird's-eye view of the morphology and affinities of the entire animal kingdom from an elevation built up of but the first hundred pages or so of his volume.
Faults of arrangement such as those we allude to render less justifiable than it would be in a treatise of smaller compass the adoption of such a binary division of Vertebrata as that which classes them apart as they are warm or cold-blooded. Of this, as being confessedly an "artificial and convenient" division (p. 7, Vol. I.), we will not farther speak, but we cannot thiqk it in any true sense " convenient " to endorse in a scientific work the popular error which, in spite of "clothes,"—and indeed of much deeper "philosophy," classes the naked together with the scaly quadrupeds, and speaks of them both alike as "reptiles." Animals like frogs ought to be called " amphibia," as they alone of all animals are truly amphibious ; and animals like lizards ought to have the name " reptiles " exclusively to themselves, seeing that, as V. Baer said in his own quaint way long ago, they have nothing in common with amphibia except that they are neither fish, nor birds, nor mammals. Yet Professor Owen, in the very page (Vol. I., p. 6) in which he puts forth several other arguments tending to this conclusion, says, "The broad and well marked characters afforded by the respiratory system will probably give permanence to the division, so convenient for most purposes, of the Vertebrate pro- vince into the four great classes above defined, viz., Pisces, Reptilia, Ares, Mammalia."
Blots of a more purely real and less formal character are pre- sented to us in what we must speak of as the deadly heresies relating to the tympanic bone, to the fornix of marsupials, and, finally, to the value of embryology as a test of morphological identity. These heresies have been again and again refuted, and yet they are still adhered to with that "adamantine adheres- cence " with which Lord Macaulay clung to his unification of the two Penns, and ignored Mr. Forster's demonstration of their separate individuality. The tympanic heresy consists in affirming that the ring of bone which supports our ear-drum is but a stunted representative of the pedicle on which the lower jaw of the oviparous vertebrate swings. It is twice unmistakably and emphatically laid down as an article of faith, at p. 303 and p. 314 of Vol. II. There are innumerable scientific arguments to show its utter untenability, but these it is needless to give here, inasmuch as a simple inspection of an animal as accessible and easily pro- curable as a frog, will show that he has an ear-drum or tympanic ring underlying the transparent skin of the side of his head, and co-existing with, and therefore unquestionably not homologous with, nor a representative of, a pedicle for the lower jaw.