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23 chapters
PREFACE
PREFACE
This book is not intended to be a full or detailed history of animal morphology: a complete account is given neither of morphological discoveries nor of morphological theories. My aim has been rather to call attention to the existence of diverse typical attitudes to the problems of form, and to trace the interplay of the theories that have arisen out of them. The main currents of morphological thought are to my mind three—the functional or synthetic, the formal or transcendental, and the materia
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CHAPTER I
CHAPTER I
The first name of which the history of anatomy keeps record is that of Alcmaeon, a contemporary of Pythagoras (6th century B.C. ). His interests appear to have been rather physiological than anatomical. He traced the chief nerves of sense to the brain, which he considered to be the seat of the soul, and he made some good guesses at the mechanism of the organs of special sense. He showed that, contrary to the received opinion, the seminal fluid did not originate in the spinal cord. Two comparison
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CHAPTER II
CHAPTER II
For two thousand years after Aristotle little advance was made upon his comparative anatomy. Knowledge of the human body was increased not long after his death by Herophilus and Erasistratus, but not even Galen more than four centuries later made any essential additions to Aristotle's anatomy. During the Middle Ages, particularly after the introduction to Europe in the 13th century of the Arab texts and commentaries, Aristotle dominated men's thoughts of Nature. The commentary of Albertus Magnus
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CHAPTER III
CHAPTER III
Cuvier was perhaps the greatest of comparative anatomists; his work is, in the best sense of the word, classical. Like all his predecessors, like Aristotle, like the Italian anatomists, Cuvier studied structure and function together, even gave function the primacy. Some functions, he says, [41] are common to all organised bodies—origin by generation, growth by nutrition, end by death. There are also secondary functions. Of these the most important, in animals at least, are the faculties of feeli
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CHAPTER IV
CHAPTER IV
Science, in so far as it rises above the mere accumulation of facts, is a product of the mind's creative activity. Scientific theories are not so much formulæ extracted from experience as intuitions imposed upon experience. So it was that Goethe, who was little more than a dilettante, [70] seized upon the essential principles of a morphology some years before that morphology was accepted by the workers. Goethe is important in the history of morphological method because he was the first to bring
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CHAPTER V
CHAPTER V
E. Geoffrey made an experiment, unsuccessful but instructive. He tried to found a science of pure morphology; he failed: his failure showed, once and for all, that a pure morphology of organic forms is impracticable. Already, in 1796, in one of his earliest memoirs, [86] Geoffroy was guided by the idea that Nature has formed all living things upon one plan. Organs which seem anomalous are merely modifications of the normal; the trunk of an elephant is formed by the excessively prolonged nostrils
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CHAPTER VI
CHAPTER VI
Geoffroy's theories were not generally accepted by his contemporaries, but his methods had considerable influence, especially in France, where many made essays in pure morphology. His chief follower was Serres, who is mentioned indeed in the Philosophie anatomique as a fellow-worker. Serres was primarily a medical anatomist; his interest lay in human anatomy and embryology, normal and pathological. His best early work was an Anatomie comparée du cerveau (1824-26), which met with a flattering rec
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CHAPTER VII
CHAPTER VII
To complete our historical survey of the morphology of the early 19th century we have now to turn back some way and consider the curious development of morphological thought in Germany under the influence of the Philosophy of Nature . We have already seen many of these notions foreshadowed by Goethe, who had considerable affinity with the transcendentalists, but the full development of transcendental habits of thought comes a little later than the bulk of Goethe's scientific work, and owes more
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CHAPTER VIII
CHAPTER VIII
Richard Owen is the epigonos of transcendental morphology; in him its guiding ideas find clear expression, and in his writings are no half-truths struggling for utterance. Fig. 4.—Ideal Typical Vertebra. (After Owen.) But he was, though a staunch transcendentalist, an eclectic of the older ideas current in his time; for he picked out what was best in the older systems—Cuvier's teleology, Geoffroy's principle of connections, Oken's idea of the serial repetition of parts. In particular, he assimil
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CHAPTER IX
CHAPTER IX
Von Baer was recognised as the founder of embryology even by his contemporaries. His predecessors, Aristotle, [166] Fabricius, [167] Harvey, [168] Malpighi, [169] Haller, [170] Wolff, [171] had made a beginning with the study of development; von Baer, by the thoroughness of his observation and the strength of his analysis, made embryology a science. It was to one of the German transcendentalists that von Baer owed the impulse to study development. Ignatius Döllinger, Professor in Würzburg, induc
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CHAPTER X
CHAPTER X
Pander's work of 1817 was the forerunner of an embryological period in which men's hopes and interest centred round the study of development. "With bewilderment we saw ourselves transported to the strange soil of a new world," wrote Pander, and many shared his hopeful enthusiasm. K. E. von Baer's Entwickelungsgeschichte was by far the greatest product of this time, but it stands in a measure apart; we have in this chapter to consider the lesser men who were Baer's contemporaries, friends, follow
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CHAPTER XI
CHAPTER XI
With the founding of the cell-theory by Schwann in 1839 an important step was taken in the analysis of the degrees of composition of the animal body. Aristotle had distinguished three—the unorganised material, itself compounded of the four primitive elements, earth and water, air and fire, the homogeneous parts or tissues and the heterogeneous parts or organs, and this conception was retained with little change even to the days of Cuvier and von Baer. Those of the old anatomists who speculated o
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CHAPTER XII
CHAPTER XII
The influence of the cell-theory on morphology was not altogether happy. The cell-theory was from the first physiological; cells were looked upon as centres of force rather than elements of form, and the explanation of all the activities of the organism was sought in the action of these separate dynamic centres. There resulted a certain loss of feeling for the problems of form. The organism was seen no longer as a cunningly constructed complex of organs, tissues and cells; it had become a mere c
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CHAPTER XIII
CHAPTER XIII
It is a remarkable fact that morphology took but a very little part in the formation of evolution-theory. When one remembers what powerful arguments for evolution can be drawn from such facts as the unity of plan and composition and the law of parallelism, one is astonished to find that it was not the morphologists at all who founded the theory of evolution. It is true that the noticeable resemblances of animals to one another, the possibility of arranging them in a system, the vague perception
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CHAPTER XIV
CHAPTER XIV
At the time when Darwin's work appeared there already existed, as we have seen, a fully formed morphology with set and definite principles. The aim of this pre-evolutionary morphology had been to discover and work out in detail the unity of plan underlying the diversity of forms, to disentangle the constant in animal form and distinguish from it the accessory and adaptive. The main principle upon which this work was based was the principle of connections, so clearly stated by Geoffroy. The princ
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CHAPTER XV
CHAPTER XV
Haeckel and Gegenbaur set the fashion for phylogenetic speculation, and up to the middle 'eighties, when the voice of the sceptics began to make itself heard, the chief concern of the younger morphologists was the construction of genealogical trees. The period from about 1865 to 1885 might well be called the second speculative or transcendental period of morphology, differing only from the first period of transcendentalism by the greater bulk of its positive achievement. It must be remembered th
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CHAPTER XVI
CHAPTER XVI
In his papers of 1866 and 1867 Kowalevsky had remarked upon the widespread occurrence of a certain type or fundamental plan of early embryonic development, characterised by the formation, through invagination, of a two-layered sac, whose cavity became the alimentary canal. This developmental archetype was manifested in, for instance, Sagitta , [424] Rana , [425] Lymnæa , [426] Astacus , [427] Phoronis , [428] Asterias , [429] Ascidia , [428] the Ctenophora , [428] and Amphioxus . [428] He notice
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CHAPTER XVII
CHAPTER XVII
" Of late the attempt to arrange genealogical trees involving hypothetical groups has come to be the subject of some ridicule, perhaps deserved. But since this is what modern morphological criticism in great measure aims at doing, it cannot be altogether profitless to follow this method to its logical conclusions. That the results of such criticism must be highly speculative, and often liable to grave error, is evident." The quotation is from Bateson's paper of 1886, and it is symptomatic of the
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CHAPTER XVIII
CHAPTER XVIII
Until well into the 'eighties animal morphology remained a purely descriptive science, content to state and summarise the relations between the coexistent and successive form-states of the same and of different animals. No serious attempt had been made to discover the causes which led to the production of form in the individual and in the race. It is true that evolution-theory had offered a simple solution of the great problem of the unity in diversity of animal forms, but this solution was form
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CHAPTER XIX
CHAPTER XIX
We have laid stress upon the distinction established by Roux between the two stages of development—the automatic and the functional—because of the light which it seems to throw upon the phylogenetic relation of form to function. We have pointed out, too, the paramount rôle that function plays in Roux's theories of development and heredity, and we have brought out the close kinship existing between his theory and that of Lamarck. For Roux, as for Lamarck, the function creates the organ, and it is
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CHAPTER XX
CHAPTER XX
To write a history of contemporary movements from a purely objective standpoint is well recognised to be an impossible task. It is difficult for those in the stream to see where the current is carrying them: the tendencies of the present will only become clear some twenty years in the future. I propose, therefore, in this concluding chapter to deal only with certain characteristics of modern work on the problems of form which seem to me to be derived directly from the older classical tradition o
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CHARLES DARWIN
CHARLES DARWIN
THE ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION. 6s. net. Popular Edition. 2s. 6d. net. Also in Paper Covers, 1s. net. DESCENT OF MAN, AND SELECTION IN RELATION TO SEX. With Illustrations. 3s. 6d. net. VARIATION OF ANIMALS AND PLANTS UNDER DOMESTICATION. Woodcuts. 2 vols. 15s. net. Popular Edition. 7s. 6d. net. EXPRESSION OF THE EMOTIONS IN MAN AND ANIMALS. With Illustrations. 9s. net. Popular Edition. 3s. 6d. net. VARIOUS CONTRIVANCES BY WHICH ORCHIDS ARE FERTILIZED BY INSECTS. Woodcuts. 7s
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WORKS BY EDWARD HALFORD ROSS,
WORKS BY EDWARD HALFORD ROSS,
Of the John Howard McFadden Researches; the Lister Institute of Preventive Medicine, London; and sometime Health Officer, Port Said, the Suez Canal District and Cairo. THE REDUCTION OF DOMESTIC MOSQUITOS. Instructions for the use of Municipalities, Town Councils, Health Officers, Sanitary Inspectors, and Residents in Warm Climates. Demy 8vo. 5s. net . THE REDUCTION OF DOMESTIC FLIES. With Illustrations. Demy 8vo. 5s. net ....
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