DR. OGILVIE'S MASTER-BUILDER'S PLAN. * IT is about fifty years since
Oken first promulgated his theory on a pervading typical law of formation, at all events as regarded vertebrate animals ; close observation of the upper part of the backbone, where it terminates in the base of the skull, having, it is said, originally suggested the idea to him. Since that time Oken's views have been tested, received, and expounded in a gra- dually accelerating ratio. The first popular illustration of Oken's principle in this country was published we believe in 1833, when Sir Charles Bell's well-known treatise on the human hand ap- peared. The exposition of a typical law pervading the structure of the group vertebrata was not directly Bell's object, so much as the illustration of design according to the scheme of the Bridge- water Series, in which the treatise on the hand originally ap- peared. The enforcement of Oken's law could not, however, be avoided ; because the object of the great English anatomist was to prove design by tracing the upper extremity (for the subject ex- tended beyond the title of "hand,") from its germ in the fin of the fish, through the paddle of the turtle, the wing of the bird, the paw of the lion or the bear, the hoof of the horse, the foot of the camel, the long-clawed feet of the sloth, the all but hand and arm of the ape and monkey, till it exhibits its perfect form in the arm and hand of man. But although natural theo- logy was the primary object of Sir Charles Bell, it is probable that his treatise better illustrated the typical law of formation, • The Master-Builder's Plan, or the Principles of Organic Architecture as indi- eafed in the Typical Forms of Animals. By George Ogilvie, M.D,, Lecturer OU the Institutes of Medicine, &e., in the Mari-sae' College and University, Aberdeen. Published by Longman, and Co.
than if he had written with an anatomical purpose. The neces- sity of showing design on a uniform plan, with the perpetual adaptation and extension of the primal law to the endless require- ments of different classes of animals, enforced Oken's law in the particular kind of structure treated of with more fulness and feli- city than a mere anatomist would have attained.
A few years later, Dr. Southwood Smith incidentally exhibited the typical law more extensively and with greater felicity than it has perhaps even yet been done, though in physiology rather than anatomy. In "The Philosophy of Health,' the uniform opera- tion of the principle of nutrition both in animal and vegetable life, with its exquisite adaptation to circumstances, was really de- monstrated. Where locomotion is necessary, as in animals, diges- tion and motion are continuously provided for by an internal stomach ; where the object to be nourished is fixed, and draws its nutriment from an extended space as a tree, the stomach is ex- ternal, in fact turned inside out, becoming roots. But in both eases, the same principle, that of the spongiole, is resorted to. Since the time of Southwood Smith's publication various emi- nent men have devoted, themselves to the elucidation of Oken's theory with equal industry and knowledge, if not with the power of popular illustration possessed by Charles Bell and Southwood Smith. Of these Owen is the most distinguished and systematic inquirer ; but his labours have been confined to the vertebrate. Numerous writers have contributed to the three or four other groupes of aniniantia. The object of The Master Builder's Plan—a somewhat affected title,—is to bring together the results of these scattered labours, so as to exhibit popularly and briefly the conclusions which Dr. Ogilvie and others think may be drawn from modern anatomical researches, and also to trace the signs of a uniform plan or typical law throughout the whole of animal life. In the vertebrate this is done easily enough. The back-bone of a neckless fish, with its fins and caudal appendage, is organically the same kind of struc- ture, as man with his neck adapted to the "os sublime," and his arms and hands, lower limbs and feet ; while, even to the crawling serpent, the ribs throughout fulfil one purpose, with endless adaptations to the particular ends in view. In the articulate, where the skeleton is external, and the ring is substituted for the vertebra, the typical law of the group is visible throughout. We do not think its consistency with the vertebrate is so clearly proved. No doubt by presenting the typical form of each group in a diagram, a strong similarity is respectively seen between the skeletons, and the nervous, circulating, and alimentary systems : but this similarity seems rather forced than natural. In the loiter groups of mollusca, radiate, and protozoa, the structural re- semblance is still less evident, though what appears a typical law may prevail throughout in the embryotic germ.
The book is not so pervadingly popular as its author intended it should be. This may in part arise from the nature of the sub- ject. Resemblances which nature has so veiled, that generation after generation of anatomists have passed without observing them, and which were only detected by special genius, require something of that attention to realize which is necessary to fol- low mathematical proof, or indeed proof of any kind where the connecting links are slender. An equal cause of something like dryness we believe to be the confined limits to which Dr. Ogilvie has restricted himself ; for expositions of novel views, especially of this nature require considerable space. That it is not inherent in the author is clear enough, from the plain and popular style in which he handles matters of a general kind ; flight for in- stance.
"In the varied mechanism of flight we have another illustration of the same principle. This of all the faculties of animal life is perhaps the one which—but for our familiarity with it—would make the greatest impression -upon us. That a gross material body should be capable of soaring at will into the impalpable air, has indeed, from the very first, excited in reflecting minds sentiments of wonder, not unmixed with envious longings to appro- priate to ourselves what appeared the one great endowment in which we are surpassed by the lower animals. But in this respect human ingenuity has met with but very partial success. Though by taking advantage of the buoyancy of certain gases, man may float himself up in a balloon, yet in so far as his movements in the air can be turned to any practical use, or are at all of the nature of proper flight, he has advanced no nearer his object after the lapse of centuries than in his first essays." • • "In birds the requisite power in the air is given by the stroke of the vanes of quill-feathers, supported by bones answering to those of the arm, the hand and finger bones being rudimentary. But birds are not the only flying vertebrates, though they are so in a peculiar sense, and possess the faculty in the highest degree of perfection, their whole conformation being adapted to the function, and the construction of their wings possessing spe- cial advantages for the purpose. In all the other classes we can point to species which have a limited power of the same nature. "Thus we have the flying-fish, which, though probably dependent, like others of its kind, on the stroke of its tail against the water for its first pro- jection into the air, can to a certain extent support itself in that element by its immense fore-fins. Here, therefore, as in the bird, the power of flight, such as it is, depends on the fore-limbs ; but the moving surface is different, for the arm bones are rudimentary in the fish, and feathers are unknown as tegumentary appendages. Their place is supplied by a fold of skin stretched over the fin-rays, which represent the finger bones of the higher Vertebrate, elements, as we have seen, but little developed in the bird. The hand, in- stead of being lost among the feathers, as in the latter, forms in the fish the whole free extremity, and is directly attached to the body of the animal. "Among reptiles, an extinct species, the Pterodactyle, had also the power of flight. In this animal the fold of skin seems to have been stretched over one finger only, which was immensely elongated in proportion to the rest."
Another example may be taken from one of those apparent laws of nature, the reason of whose uniformity man with his present knowledge cannot see, as the importance ascribed to the number five.
"Another point noticed by Professor Owen, is the constancy with which the number five is indicated in the digits of all the Aigher Vertebnita.
the class of fishes, indeed, in which they have only the rudimentary forra rays, their number is indefinite, varying from the single jointed filament, that constitutes the limb of the lepidoairen, to the large _pectoral fin of the skate, in which there may be as many as fifty rays. But in all eases ie which they assume the character of fingers and toes, we have clear indica. lions of five being the typical number. This they never exceed, and whez they fall short of it, there still subsists a relation among the remaining bones, enabling us to determine the precise digits that are lost and re- tained ; to point out, for example, the finger in the hand of man that an- swers to the forefoot of the horse, and the toe that corresponds to its hind. foot ; nay, the very nail in the hand or foot which becomes, by excess of development, the great hoof of the horse.' This he determines to be the middle digit, the representative of that finger which even in the halo hand shows a slight superiority in length, vindicating as it were its position as
'the most constant of all in the vertebrate series, and most entitled to be viewed as the persistent representative of the terminal segments of the pri. be saject to mitive ray of the lepidesiren.' In the ox, again, the bones which suppon
the cloven hoof answer to the middle and ring fingers. • • • "Five is the prevailing number in this class [the radiata]. Not only is the circumference of the body divisible into five equal and similar seements, but even the more minute details of its organization appear to the same law. Every plate of the sea-urchin is built up of pentagonal particles. The skeletons of the digestive, the aquiferous, and tegumentary systems equally present the quinary arrangement ,.and even the hard frame- work of the disc of every sucker is regulated by this mystic number."
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