Lorenz. Under this name the great naturalist of the transcendental or deductive school is commonly known; but his real name was "Lorenz Ockenfuss," under which he was baptized at Bohlsbach, Württemberg, being born in that small Swabian village on the 1st of August 1779. As "Ockenfuss" he was entered at the natural history and medical classes in the university of Würzburg; whence he proceeded to that of Göttingen, where he became a private teacher, and abridged his name to "Okon." As Lorenz Oken, he published, in 1802, his small work entitled *Grundriss der Naturphilosophie, der Theorie der Sinne, und der daraus gegründeten Classification der Thiere*, 8vo.

This is the first of the series of works which placed Oken at the head of the "natur-philosophie" or physio-philosophical school of Germany. In it he extended to physical science the philosophical principles which Kant had applied to mental and moral science. Oken had, however, in this application, been preceded by Fichte, who, acknowledging that the materials for a universal science had been discovered by Kant, declared that nothing more was needed than a systematic co-ordination of these materials; and this task Fichte undertook in his famous *Doctrine of Science* (Wissenschafts-lehre), the aim of which was to construct *a priori* all knowledge. In this attempt, however, Fichte did little more than indicate the path; it was reserved for Schelling fairly to enter upon it; and for Oken, following him, to explore its mazes yet farther, and to produce a systematic plan of the country so surveyed.

In the *Grundriss der Naturphilosophie* of 1802, Oken sketched the outlines of the scheme he afterwards devoted himself to perfect. The position advanced in that remarkable work, and to which he ever after professed himself to adhere, is this—"that the animal classes are virtually nothing else than a representation of the sense-organs, and that they must be arranged in accordance with them." Agreeably with this idea, Oken contends that there are only five animal classes:—1. The Dermatozoa, or Invertebrata; 2. the Glossozoa, or Fishes, as being those animals in which a true tongue makes, for the first time, its appearance; 3. the Rhinozoa, or Reptiles, wherein the nose opens for the first time into the mouth and inhales air; 4. the Otozoa, or Birds, in which the ear for the first time opens externally; and 5. the Ophthalmozoa, or mammals, in which all the organs of sense are present and complete, the eyes being movable and covered with two lids.

In 1803 Oken made another characteristic advance in the application of the *a priori* principle, by a book *On Generation* (*Die Zuegung*, Frankl., 8vo), wherein he maintained the proposition "that all organic beings originate from, and consist of, vesicles or cells." These vesicles, when singly detached and regarded in their original process of production, are the infusorial mass or protoplasm (ur-schleim), from whence all larger organisms fashion themselves, or are evolved. Their production is therefore nothing else than a regular agglomeration of infusoria; not, of course, of species already elaborated or perfect; but of mucous vesicles or points in general, which first form themselves by their union or combination into particular species."

This doctrine is strikingly analogous to the generalized results of the ablest microscopic observations on the development of animal and vegetable tissues which have been prosecuted of late years.

One year after the production of this remarkable treatise, Oken advanced another step in the development of his system; and in a volume published in 1806, in which Keiser assisted him, entitled, *Beiträge zur Vergleichenden Zoologie, Anatomie, und Physiologie*, he demonstrated that the intestines originate from the umbilical vesicle, and that this corresponds to the vitellus or yolk-bag. Caspar Friedrich Wolff had previously proved this fact in the chick; but he did not see its application as evidence of a general law. Oken showed the importance of the discovery as an illustration of his system. In the same work Oken described and re-called attention to the corpora Wolfiana, or "primordial kidneys," as they are now termed and recognised. At this period, the enlightened Duke of Weimar and the poet Goethe (who repaid the friendship of his prince by the reflection of his own undying renown), were bringing to perfection the plan of general education for the grand-duchy. The university of Jena, under these auspices, had been rapidly rising to pre-eminence; not through the wealth of its endowments or by any artificial excitement, but through the celebrity of the professors and members, whose noble aspirations were stimulated by the encouraging eye of the prince, and the observant care of his minister for education. Under these auspices had been fostered a Griesbach, Fichte, Shelling, Feuerbach, the two Humboldts, Hufeland, and Schlegel.

The reputation of the young privat-dozent of Göttingen had reached the ear of Goethe, and in 1807 Oken was invited to fill the office of "Extraordinary Professor of the Medical Sciences" in the university of Jena. He accepted the call, and selected for the subject of his "Inaugural discourse," his ideas on the "Signification of the bones of the skull," based upon a discovery he had made in the previous year. This famous lecture was delivered in the presence of Goethe, as privy-councillor and rector of the university, and was published by the young professor in the same year, with the title, *Über die Bedeutung der Schädelknochen, ein Programm beim Antritt der Professur an der Gesammt-Universität zu Jena*, 4to, 1807. Of the relation of this essay to the vertebral theory of the skull, we shall subsequently offer a few remarks.

With regard to the origin of the idea, Oken narrates in his *Isis*, that, walking one autumn-day in 1806, in the Hartz forest, he stumbled upon the blanched skull of a deer, picked up the partially dislocated bones, and, contemplating them for a while, the truth flashed across his mind, and he exclaimed, "It is a vertebral column!" At a meeting of the German naturalists, held at Jena, some years afterwards, Professor Kieser gave an account of Oken's discovery in the presence of the grand-duke, which account is printed in the *Tageblatt*, or "proceedings," of that meeting. The professor states that Oken communicated to him his discovery when journeying in 1806, to the Isle of Wangeroog. On their return to Göttingen, Oken explained his ideas by reference to the skull of a turtle in Kieser's collection, which Oken disarticulated for that purpose with his own hands. "It is with the greatest pleasure," writes Kieser, "that I am able to show here the same skull, after having it thirty years in my collection. The single bones of the skull are marked by Oken's own hand-writing, which may be so easily known." There was a cause, as we shall presently see, for this circumstantial testimony.

Oken having delivered and printed his *Introductory Lecture* in 1807, informs us, in the heft vii. of his *Isis*, that he presented copies to Goethe and to other members of the grand-duke's government. "Goethe was so pleased with my discovery as to invite me to stay with him during the Easter week of 1808 in his house at Weimar, which invitation I accepted."

The range of Oken's lectures at Jena was a wide one, and they were highly esteemed. They embraced the subjects of natural philosophy, general natural history, zoology, comparative anatomy, the physiology of man, of animals, and of plants. The spirit with which the professor grappled with the vast scope of science is characteristically illustrated in his essay *Über das Universum als Fortsetzung des Sinnensystems*, 4to, 1808. In this work he propounds "that organism is none other than a combination of all the universe's activities within a single individual body." This doctrine led him to the conviction "that world and organism are one in kind, and do not stand merely in harmony with each other."

In the same year he published his *Erste Ideen zur Theorie des Lichts*, &c., in which he advanced the proposition, that "light could be nothing but a polar tension of the ether, evoked by a central body in antagonism with the planets; and that heat was none other than the motion of this ether." Here Oken may be said to have anticipated the doctrine of the "correlation of physical forces."

In 1809, he extended his system to the mineral world, arranging the ores, not according to the metals, but agreeably to their combinations with oxygen, acids, and sulphur. In 1810 Oken summed up his several views on organic and inorganic natures into one compendious system. The first edition of his *Lehrbuch der Naturphilosophie* appeared in that and the following years, in which he sought to bring his several doctrines into mutual connection, and to "show that the mineral, vegetable, and animal kingdoms are not to be arranged arbitrarily in accordance with single and isolated characters, but to be based upon the cardinal organs or anatomical systems, from which a firmly-established number of classes would necessarily be evolved; that each class, moreover, takes its starting point from below, and consequently that all of them pass parallel to each other." That, "as in chemistry, where the combinations follow a definite numerical law, so also in anatomy, the organs—in physiology, the functions—in natural history, the classes, families, and even genera of minerals, plants, and animals—present a similar arithmetical ratio."

Three editions of this extraordinary book have appeared, each more fully elaborated than the former. An epitome of the work will presently be given. In continuing the personal history of the author of the *Naturphilosophie*, we may first mention that, on Goethe's recommendation, Oken was honoured, on the publication of the first edition of the *Lehrbuch* in 1810, with the title of "Hof-rath," or court-counsellor. In 1812 he was appointed "ordinary professor of natural sciences" in the university of Jena. In 1816 he commenced the publication of his well-known periodical, entitled *Isis, ein Encyclopädische Zeitschrift, vorzüglich für Naturgeschichte, vergleichende Anatomie und Physiologie*, 4to. In this journal not only appeared essays and notices on the natural sciences, but on other subjects of interest; poetry, and even comments on the politics of other German states, were occasionally admitted. This led to representations and remonstrances from the governments criticized or impugned, and the court of Weimar gave Oken the alternative of suppressing the *Isis*, or of resigning his professorship. He chose the latter. The publication of the *Isis* at Weimar was prohibited. Oken made arrangements for its issue at Rudolstadt, and this continued uninterruptedly until the year 1848.

The independent spirit manifested by Oken excited his courtly enemies to harsher measures. An accusation was preferred against Oken as a member of a forbidden "secret democratic society"; he stood his trial and was acquitted. He thereupon retired for a while into private life, occupying himself with the editorship of the *Isis*, and with his scientific works. Amongst these may be cited the *Lehrbuch der Naturgeschichte*, 1815-1825; his *Handbuch der Naturgeschichte zum Gebrauch bei Vorlesungen*, 1816-1820; and his *Naturgeschichte für Schulen*, 8vo, 1821. In these manuals Oken considered that he had arranged for the first time the genera and species in accordance with the only true or physio-philosophical principles; stating briefly everything of vital importance respecting them; and that it was the first attempt to frame a truly scientific history of nature.

In 1821 Oken promulgated, in his *Isis*, the first idea of the annual general meetings of the German naturalists and medical practitioners, which happy idea was realized in the following year, when the first meeting was held at Leipzig in 1822. They have been continued ever since in Germany; and similar annual scientific gatherings have been adopted in other countries, of which the "British Association for the Advancement of Science" is an instance, avowedly, at its origin, organized after the German or Okenian model. The writer of the present notice attended the German annual meeting at Freiburg in 1838, and heard a fervid extempore address by Oken of upwards of an hour's duration, in which the rare eloquence of the gifted man, and the sympathy and respect of his countrymen for the orator, were strikingly manifested.

In 1828 Oken resumed his original humble duties as "private teacher" in the newly-established university of Munich; and soon afterwards he was appointed "ordinary professor" in the same university. In 1832, on the proposition by the Bavarian government to transfer Oken to a professorship in a provincial university of the state, he resigned his appointments and left the kingdom.

Switzerland has the honour of affording the final place of refuge, with means of an independent pursuit of science, to this philosophic and patriotic naturalist. Oken was appointed in 1833 to the professorship of natural history in the then recently-established university of Zurich. There he continued to reside, fulfilling his professional duties and promoting the progress of his favourite sciences, to the period of his demise, in the seventy-second year of his age.

In his *Lehrbuch der Naturphilosophie*, of which a translation of the last edition, by A. Tulk, Esq., has been published by the Ray Society, under the title of *Elements of Physio-philosophy*, Oken begins by asserting that philosophy, as the science which embraces the principles of the universe or world, is only a logical conception; but it may conduct to the real conception. Thus the mathematics are principles (or a philosophy) of which the universe is the reality. "The world consists of two parts—one apparent, real, or material; the other non-apparent, ideal, spiritual. Hence there are two divisions of philosophy,—viz., pneumatico- and physio-philosophy."

The latter is the subject of this treatise.

Its object is "to show how, and in accordance with what laws, the material took its origin; to portray the first periods of the world's development from nothing; how the elements and heavenly bodies originated; in what method by self-evolution into higher and manifold forms they separated into minerals, became finally organic, and in man attained self-consciousness." Physio-philosophy is, therefore, in fact, the history of creation, a name under which it was taught by the most ancient philosophers,—viz., as "cosmogony."

Man, being the crown of nature's development, must comprehend every thing that has preceded him. "In a word, man must represent the whole world in miniature." Hence the laws of spirit are not different from the laws of nature—both are transcripts of each other.

Physio-philosophy, therefore, is more important than pneumatico-philosophy, because nature is antecedent to the human spirit.

And the whole of philosophy consists in the demonstration of the parallelism that exists between the activities of nature and of spirit.

But inasmuch as the spiritual existed before the real, and gave it birth, physio-philosophy must commence from the spirit.

It is divided into three parts: the first, treating of spirit and its activities; the second, of the individual phenomena or things of the world; the third, of the continuous operation of spirit in the individual things.

It would be impossible, within the limits of this article, to follow Oken through his extraordinary development of the science he has thus described. Every sentence is a link in the chain of argument, which could not be extracted so as to be intelligible, nor would it endure further condensation. It must suffice to state that he traces, agreeably with his system, the evolutions of every form of being, organic and inorganic, in a regular series, from the simple element to the most complex shapes. "Polarity is the first force which appears in the world," "Galvanism is the principle of life," "the vital force," "The galvanic process," he says, "is one with the vital process," "There is no other vital force than the galvanic polarity." Oken, then, contends that organism is galvanism, residing in a thoroughly homogeneous mass. A galvanic pile, pounded into atoms, must become alive. In this manner nature brings forth organic bodies. The basis of electricity is the air; of magnetism, metal; of chemistry (the name he gives to the influence that produces chemical combination), salts. The basis of galvanism, in like manner, is the organic mass. Accordingly, whatever is organic is galvanic; whatever is alive is galvanic. Life, organism, galvanism, are one. Life is the vital process; the vital process is an organic or galvanic process. Galvanism is the basis of all the processes of the organic world.

At the creation God created a mass of organisms of no larger size than an infusorial point. Whatever is larger has not been created but developed. "So," says Oken, "the Bible teaches us." God did not make man out of nothing, but took an elemental body then existing, an earth-clod or carbon, moulded it into form, thus making use of water, and breathed into it life,—viz., air, whereby galvanism or the vital process arose.

Organization is produced by the co-operating influence of light and heat. "The other imparts the substance, the heat the form, the light the life."

The life of an inorganic body is a threefold action of the three terrestrial elements, in which three processes galvanism consists. The nutrient process is magnetic, present and entire in every part of the body, and wheresoever it is withdrawn there is death. It operates according to the laws of crystallization. The digestive process acts according to the laws of chemism, which is not only the process of liquefaction, but the process of formation or creation of new organic matter. The digestive process converts the inorganic to the organic mass. It is the formation of mucus. The chyle is strictly a mucus. Into mucus the air finally settles down by the process of oxidation, called the respiratory process. By this the juices emerge from their state of indifference, by which each point of the juice becomes polar towards every other; all are mutually attracted, all repelled, and thereby a decided circulation-motion is originated.

Every globule of sap or mucus is per se indifferent. It has, therefore, a natural affinity for each of the three elements comprehended in the organism. By respiration it is united Oken. to the element air, by digestion to the element water, by nutrition to the element earth. These three processes constitute the galvanic process. Thus the galvanic circle is complete, and motion is the manifestation of galvanism. The process of motion is synonymous with the galvanic process—this is the vital process.

The distinction between the organic and the inorganic is self-motion. The organic is destroyed so soon as motion disappears in it; the inorganic is destroyed so soon as motion enters it.

The above will serve as an idea of the spirit of the work, and of the author's style and treatment of the most recondite questions. We now return to Oken's essay on the Signification of the Bones of the Head, on which, perhaps, his reputation as an original discoverer is best founded.

There nevertheless still prevails confusion, or indistinctness of ideas, in the opinions set forth relative to Oken's claims to, or share in, the discovery of the vertebral nature and arrangement of the bones of the skull.

All Oken's writings are eminently deductive illustrations of a foregone and assumed principle, which, with other philosophers of the transcendental school, he deemed equal to the explanation of all the mysteries of nature.

According to Oken, the head was a repetition of the trunk—a kind of second trunk, with its limbs and other appendages; this sum of his observations and comparisons—few of which he ever gave in detail—ought ever to be borne in mind in comparing the share taken by Oken in homological anatomy with the progress made by other cultivators of that philosophical branch of the science.

The idea of the analogy between the skull, or parts of the skull, and the vertebral column, had been previously propounded and ventilated in their lectures by Autenreith and Kielmeyer, and in the writings of Jean-Pierre Frank. By Oken it was applied chiefly in illustration of the mystical system of Schelling—the all-in-all and all-in-every-part. From the earliest to the latest of Oken's writings on the subject, "the head is a repetition of the whole trunk with all its systems." The brain is the spinal chord; the cranium is the vertebral column; the mouth is intestine and abdomen; the nose is the lungs and thorax; the jaws are the limbs; and the teeth the claws or nails." Spix, in his folio Cephalogenesia, 1818, richly illustrated comparative craniology, but presented the facts under the same transcendental guise; and Cuvier ably availed himself of the extravagancies of these disciples of Schelling to cast ridicule on the whole inquiry into those higher relations of parts to the archetype, which Professor Owen has called "general homologies."

"M. Spix," Cuvier writes, "makes this bone, which I call 'posterior frontal,' the 'scapula' of the upper limb of the head; and M. Oken, according to the same mystical language, makes it the 'merry thought' (fourchette) of the upper limb of the head; for it must be remarked, that the Philosophy of Nature, in pretending to find again in the head all the parts of the trunk, acts so arbitrarily, that each of those who would apply it employ these strange denominations in a different manner."

"Cet humerus de la tête de M. Oken devient pour M. Spix le pubis de cette même tête, ou, pour parler un langage intelligible, un des osselets de l'ouie." 1

The vertebral theory of the skull had practically disappeared from anatomical science when the labours of Cuvier drew to their close. It needs only to refer to the works of his chief pupils and successors, Milne-Edwards, John Müller (Physiologie), Wagner (Lehrbuch der Zoootomie), or Agassiz (Poissons Fossiles), to have sufficient evidence of that fact. In Owen's Archetype and Homologies of the Vertebrate Skeleton, the idea of the vertebral structure of the skull was not only revived but worked out for the first time inductively, and the theory rightly stated, as follows:—"The head is not a virtual equivalent of the trunk, but is only a portion, i.e., certain modified segments of the whole body. The jaws are the 'bony arches' of the first two segments; they are not limbs of the head."—(P. 176.)

Vaguely and strangely, however, as Oken had blended the idea with his a priori conception of the nature of the head, the chance of appropriating it seems to have overcome the moral sense—the least developed element in the spiritual nature—of Goethe, unless the poet deceived himself.

Comparative osteology had early attracted Goethe's attention. In 1785 he published his essay Uber den Zwischenkiefer der Menschen und der Thiere, 4to, Jena, showing that the intermaxillary bone existed in man as well as in brutes. Not a word in this essay gives the remotest hint of his having then possessed the idea of the vertebral analogies of the skull.

In 1820 (Morphologie, i, 2, p. 250), Goethe first publicly stated that thirty years before the date of that publication he had discovered the secret relationship between the vertebrae and the bones of the head, and that he had always continued to meditate on this subject. The circumstances under which the poet, in 1820, narrates having become inspired with the original idea, are suspiciously analogous to those described by Oken in 1807, as producing the same effect on his mind. A bleached skull was accidentally discovered in both instances; in Oken's it was that of a deer in the Harz Forest; in Goethe's it was that of a sheep picked up on the shores of the Lido, at Venice. Mr Buckle, in his discourse "On the Influence of Women in the Progress of Knowledge"—Fraser's Magazine, April 1858, p. 402, states:—"Goethe, strolling in a cemetery near Venice, stumbled upon a skull which was lying before him. Suddenly the idea flashed across his mind that the skull was composed of vertebrae; in other words, that the bony covering of the head was simply an expansion of the bony covering of the spine. This luminous idea was afterwards adopted by Oken and a few other great naturalists in Germany and France, but it was not received in England till ten years ago, when Mr Owen took it up, and in his very remarkable work on the Homologies of the Vertebrate Skeleton, showed its meaning and purpose as contributing towards a general scheme of philosophic anatomy." This reproduction of a disparaging statement respecting Oken necessitates the following summary of the facts:

It may be assumed that Oken, when a private teacher at Göttingen in 1806, knew nothing of this unpublished idea or discovery of Goethe; and that Goethe first became aware that Oken had the idea of the vertebral relations of the skull when he listened to the Introductory Discourse in which the young professor, invited by the poet to Jena, selected this very idea for its subject. It is incredible that Oken, had he adopted the idea from, or been aware of an anticipation by, Goethe, should have omitted to acknowledge the source—should not rather have eagerly embraced so appropriate an opportunity of doing graceful homage to the originality and genius of his patron.

The anatomist having lectured for an hour, plainly unconscious of any such anticipation, it seems hardly less incredible that the poet should not have mentioned to the young lecturer his previous conception of the vertebrocranial theory, and the singular coincidence of the accidental circumstance which he subsequently alleged to have produced that discovery. On the contrary, Goethe permits Oken to publish his famous lecture, with the same unconsciousness of any anticipation as when he delivered it; and Oken, in the same state of belief, transmits a copy to Goethe, who thereupon honours the professor with special marks of atten-

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1 Ossatures Fossiles, 4to, 1824, tom. v., pt. ii., pp. 75-85, quoted in an able article in the Quarterly Review, vol. xclii., in which the history of the Discoveries of the Archetype and Homologies of the Vertebrate Skeleton is briefly but convincingly discussed, pp. 70-80. Oken, to whom the treatise was communicated, has pretended that the idea was his own property, and has reaped the honour of it." This accusation again called out Oken, who thoroughly refuted it in an able, circumstantial, and temperate statement, in heft vii. of the Isis, 1847. Goethe's osteological essay of 1785, and the only one he printed in that century, is on a different subject. In the Morphologie of 1820-24, Goethe distinctly declares that he had never published his ideas on the vertebral theory of the skull. He could not, therefore, have sent any such essay to Oken before the year 1807. Oken, in reference to his previous endurance of Goethe's pretensions, states, that "being well aware that his fellow-labourers in natural science thoroughly appreciated the true state of the case, he confided in quiet silence in their judgment. Meckel, Spix, Ulrich, Bojanus, Carus, Cuvier, Geoffrey St Hilaire, Albers, Straus-Durckheim, Owen, Kieser, and Lichtenstein, had recorded their judgment in his favour and against Goethe. But upon the appearance of the new assault in Michelet's edition of Hegel, he could no longer remain silent."

A recent biographer of Goethe asks, "why did not Oken make the charge of plagiarism during Goethe's lifetime?" The answer is, that he at no time made such charge. He left Goethe's affirmations for what they were worth, and to produce such effect as they might with the competent historians of science. It was possible that Goethe had stated a truth; he might only have been uncandid and ungenerous. But that did not make Oken the less an original discoverer. Only when he was charged with plagiarism did he enter into the question with the view of honest self-vindication, and that both before and after Goethe's death.

As to the question of the superiority of the deductive over the inductive method in philosophy, as illustrated by the writings of Oken. His bold axiom, that heat is but a mode of motion of light,—and the idea broached in his essay on Generation (1805), viz., that "all the parts of higher animals are made up of an aggregate of infusoria or animated globular monads"—are both of the same order as his proposition of the head being a repetition of the trunk, with its vertebræ and limbs. Science would have profited no more from the one idea without the subsequent experimental discoveries of Oersted and Faraday; or by the other without the microscopical observations of Brown, Schleiden, and Schwann; than from the third notion without the inductive demonstration of the segmental constitution of the skull by Owen.

It is questionable, indeed, whether in either case the discoverers of the true theories were excited to their labours, or in any way influenced, by the a priori guesses of Oken; more probable is it that the requisite researches and genuine deductions therefrom, were the results of the correlated fitness of the stage of the science, and the gifts of its true cultivators at such particular stage.

Oken's real claims to the support and gratitude of naturalists rest on his appreciation of the true relations of natural history to intellectual progress, of its superior teachings to the mere utilitarian applications of observed facts, of its intrinsic dignity as a science.

To natural history thus worthily comprehended Lorenz Oken devoted his whole time and energies up to his last illness, which closed his career at Zurich, on the 11th of August 1851. A fine statue of the philosopher, by Drake of Berlin, has been erected to his honour in the university of Jena, where he first publicly taught.

We give a list of Oken's chief works and original essays:

1. Grundriss der Naturphilosophie, der Theorie der Sinne und der darauffolgenden Classification der Thiere. Frankf. 1802, 8°. 2. Die Zeugung. Frankf. 1805, 8°. 3. Abriss der Biologie, Göttingen, 1805, 8°. 4. Ueber die Bedeutung der Schädelknochen, ein Programm beim Antritt des Professors zu Jena, Frankf. 1807, 4°. 5. Ueber das Universum als Fortsetzung des Sinnesystems, Jena, 1808, 4°. 6. Erste Ideen zur Theorie des Lichts, der Finsterniss, der Farben, und der Wärme, Jena, 1808, 4°. 7. Grundzüge des natürlichen Systems der Erde, Jena, 1809, 4°. 8. Ueber den Werth der Naturgeschichte, Jena, 1809, 4°. 9. Lehrbuch der Naturphilosophie, 3 vols., Jena, 1809–11. —Ed. 2, Jena, 1831—Ed. 3, Zürich, 1843.—(Angl.) Elements of Physio-philosophy, Ray Society, 8°. London, 1847. 10. Lehrbuch der Naturgeschichte, Leipzig, 1813.—Weimar, 1815, 1825, 8° fig. 11. Isis, 12. Handbuch der Naturgeschichte zum Gebrauch bei Vorlesungen, Nürnberg, 1816–20, 8°. 13. Naturgeschichte für Schulen, Leipzig, 1821, 8°. 14. Études d'un Système d'Anatomie et de Physiologie, et d'Histoire Naturelle, Paris, 1812, 8°. 15. Allgemeine Naturgeschichte, Stuttgart, 1833–42, 14 vols., 8°. —Wiegmann Arch., 1835, I. p. 16. Ideen zur Classification des Animalium.—Ann. Sc. n. (2) S XIV. p. 247. 17. Das Thierreich, Stuttgart, 1836–38, 4 vols., 8°. Art. fol. 18. Idee sulla Classificazione filosofica dei tre Regni della Natura.—II Politecnico, Milano, III, 1840, pp. 8, 28.—Ann. Sc. Nat. ser. 2, XIV. p. 247. 19. Fortpflanzung der Wasserschnecken ohne Paarung.—Isis, 1817, p. 320. 20. Ueber Geschlecht und Gattung.—Isis, 1817, p. 465. 21. Aufenthalt der Meerwürmer und Anatomie von Arenicola piscatorum.—Isis, 1817, p. 466, fig. 22. Reisefragen.—Isis, 1817, p. 537. 23. Ueber Proteus anguinus und die durchgehenden Naslocher als Character der Amphibien.—Isis, 1817, p. 641, fig.; 1821, p. 271. 24. Nachtrag über die Bedeutung der Schädelknochen.—Isis, 1817, p. 1204; 1818, p. 510; 1828, pp. 353, 401; 1837, p. 575. 25. Nachtrag über die Entstehung der Därme aus dem Nebelblaschen.—Isis, 1818, p. 59. 26. Bedeutung der Knochen des Crocodilshäufels und der Nasenbeine der Vögel.—Isis, 1818, p. 278. 27. Ueber die Farben der Blumen.—Isis, 1818, p. 472. 28. Die Presswerkzeuge der Insekten entsprechen den Füssen.—Isis, 1818, p. 477, fig. 29. Verzeichniss der entomologischen Litteratur von 1790–1800.—Isis, 1818, p. 711. 30. Anatomie von Thalassema.—Isis, 1818, p. 878. 31. Bestimmung der giftigen Milbe in Persien (Rhynchoporus persicus).—Isis, 1818, p. 1567. 32. Begriff des Muschelbaues.—Isis, 1818, p. 1817. 33. Deutung des Thieres von Stronsia.—Isis, 1818, p. 2099. 34. Entstehung des ersten Menschen.—Isis, 1819, p. 1117. 35. Bein-Philosophie.—Isis, 1819, p. 1528, t. 18. 36. Ueber Pterodactylus longi- et brevirostris.—Isis, 1819, p. 1788, t. 20. 36. Ueber die Bedeutung des Insecten Leibes.—Isis, 1820, p. 552. 37. Ueber das Atmen der Pricken.—Isis, 1821, III. p. 271. 38. Nachtrag zu Richter's Aufsatz über den weiblichen Kuckucksmagen.—Isis, 1823, II. p. 225. 39. Ueber die Sammlung der vergleichenden Anatomie zu Paris.—Isis, 1823, Lit. Anz. p. 265. 40. Zahnsystem.—Isis, 1823, p. 274. 41. Bemerkungen über die Schädel der Saugthiere, Vögel und Lurche.—Isis, 1823, p. 363. 42. Ueber die Schädel der Fische und die Bedeutung des Kiemendeckels.—Isis, 1823, p. 401. t. 14, 15. 43. Ueber das Brust- und Schultergerüst und das Becken der Thiere.—Isis, 1823, p. 441. t. 16, 17. 44. Bemerkungen über die Skelete von Haarthieren.—Isis, 1823, p. 455. 45. Ueber die niederen Thiere in der Pariser Sammlung der vergleichenden Anatomie.—Isis, 1823, p. 497. t. 17. 46. Ueber die Saugthiere in der Zoologischen Sammlung zu Paris.—Isis, 1823, p. 481. t. 17. 47. Ueber die Vögel, Lurche, Fische, Weichthiere, und Kerfe in dieser Sammlung.—Isis, 1823, p. 505. 48. Ueber das Ey und die Zitzen des Schnabelthiers.—Isis, 1823, p. 1427. 49. Radlimens des pieds vers l'anus des Boas.—Féruss. Bull. 1826, VII. p. 445. 50. Bau des Bisambeutels.—Isis, 1826, p. 849, t. 6 (Féruss. Bull. 1827, X. p. 144). 51. Ueber die Bedeutung der Forts-hüllen und die Ursache des ersten Atmens.—Isis, 1827, p. 371. t. 4. 52. Ueber die Bedeutung der Schulter und Muskeln der Schädelkröte.—Isis, 1827, p. 456. 53. Ueber das Längszentrum in den Wirbeln des Menschen.—Isis, 1829, p. 306. 54. Ueber die Bedeutung der Farren- und Moos-capel.—Isis, 1829, p. 395. 55. Cypris uranotropis, Agass. aus der Isar.—Naturf. in Berl. 1829, IV. p. 414. 56. Ueber die Aufnahme der Naturwissenschaften in die Gymnasien.—Isis, 1829, p. 1225. 57. Entwicklung des Kiechlehens im Ey.—Isis, 1830, VI. p. 575. 58. Ueber das Betragen von Proteus.—Isis, 1832, p. 699. 59. Ueber die Richtung des Wurzellehens u. das Winden des Steugels.—Isis, 1834, p. 804. 60. Ueber Lepidodiren.—Isis, 1838, p. 347; 1839, p. 607; 1840, p. 407; 1843, p. 441. 61. Ueber den Steinbruch von Oeningen.—Isis, 1840, p. 282.—L. u. Br. N. Jahrh. 1843, p. 230. 62. Ueber das Periboot (Nautilus pompilius, L.)—Isis, 1835, p. 1. 63. Ueber die Schädelwürfel.—Isis, 1847. 64. Beiträge zur vergleichenden Zoologie, Anatomie und Physiologie.—Ramb. u. Würzb. 1803; 1807, 2 vols. 4°. fig.—Isis, 1818, I. p. 59, von Oken u. Kissler.