capable of creating, I would especially refer to his theory of the Cranial Homologies, which has been in our own country so beautifully carried out, modified, and proved by the extensive researches of Professor Owen.

AUTHOR'S PREFACE TO THE TRANSLATION.

It is with no readiness or pleasure that I write introductions of any kind, and usually abstain from doing so, partly because they appear to me like a kind of apology or makeshift for the author, and partly because the contents of the book itself should indicate his status or position. With regard, however, to the history of the work, some few words are certainly requisite for its Translation.

I wrote the first Edition of 1810 in a kind of inspiration, and on that account it was not so well arranged as a systematic work ought to be. Now, although this may appear to have been amended in the second and third edition, yet still it was not possible for me to completely attain the object held in view. The book has therefore remained essentially the same as regards its fundamental principles, such as those concerning the formation of matter, the protoplasmic substance (Schleim-Substanz) and vesicular form of the organic mass, the signification and function of the organs, as also the principles of classification in Minerals, Plants and Animals, so that all this is consequently as old as the first edition. It is only the empirical arrangement into series of plants and animals, that has been modified from time to time in accordance with the scientific elevation of their several departments, or just as discoveries and anatomical investigations have increased and rendered some other position of the objects a matter of necessity. This susceptibility to change will of course be persistent in the future, although the principles themselves should continue wholly unchanged; ay, the very stability of the latter will tend the more to invite the naturalist to the pursuit of empirical inquiries, by determining beforehand in what direction he is to extend his point of view, and thus spare himself the trouble of blindly and laboriously groping about in the dense labyrinth of facts. Such a work therefore as the present can only approximate completion through the progress made in science, and each new edition will supply some defect of its predecessor in the distribution or parcelling out of things.

In the first edition the principle was raised of individual bodies being alone the object of Natural History, and that in the next place they are to be arranged according to the combination of their organs or component parts, and by no means after the division or mere form of a single organ; that, for example, a special organ or anatomical system lies as the basis of each Vegetable and Animal class, and that there must be therefore as many classes, and no more, as there are cardinal organs present upon which to found them. On that account it was absolutely necessary first of all to find out these cardinal organs, and determine their rank; and, in so doing, it was shown that organs and classes are at bottom of one kind, and that the development by stages or degrees of the embryo is the antetype of that of the classes; furthermore, that each class takes its starting-point from below, and consequently that the classes do not stand simply one above the other, but fall into a series of mutually parallel ranks. Now it is this which, along with the doctrine of the infusorio-vesicular form of the organic mass, and that touching the signification of parts, as to how e. g. the blossom is the repetition of the vegetable axis or trunk, the cephalic bones that of the vertebræ, the feet of the branchiæ, and the maxillæ in turn of the feet, appears to me the cardinal point attained in my Philosophy of Nature; more especially, because it was these very doctrines which were first of all, i. e. before all the others, comprehended and almost universally adopted. The inorganic matters and activities pass, however, parallel also to the anatomical formations and functions; and that this is the case too with the spiritual or psychical functions the philosophy of the future will probably be in the condition to point out.

The reader will not expect to find that the serial arrangement of Plants and Animals, with their parallelism, has been in every instance thoroughly attained. The present is but a sample of how we are to proceed in our desire of obtaining a Natural system. With such an attempt one has something to change every year, and I have in the present translation made some alterations in respect to the Mollusca and Fishes. In this sense then it is my wish that the book may be regarded, and accordingly received with its due amount of indulgence.

LORENZ OKEN.

PREFACE.

The first principles of the present work I laid down in my small pamphlet entitled Grundriss der Naturphilosophie, der Theorie der Sinne und der darauf gegrundeten Classification der Thiere; Frankfurt bey Eichenberg, 1802, 8vo (out of print). I still abide by the position there taken, namely, 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. Thus, strictly speaking, there are only 5 Animal Classes: Dermatozoa, or the Invertebrata; Glossozoa, or the Fishes, as being those animals in whom a true tongue makes for the first time its appearance; Rhinozoa, or the Reptiles, wherein the nose opens for the first time into the mouth and inhales air; Otozoa, or the Birds, in which the ear for the first time opens externally; Ophthalmozoa, or the Thricozoa, in whom all the organs of sense are present and complete, the eyes being moveable and covered with two palpebræ or lids. But since all vegetative systems are subordinated to the tegument or general sense of feeling, the Dermatozoa divide into just as many or corresponding divisions, which, on account of the quantity of their contents, may be for the sake of convenience also termed classes. Thereby 9 classes of the inferior animals originate, but which, when taken together, have only the worth or value of a single class. So much by way of explaining the apparent want of uniformity in the system.

I first advanced the doctrine, that all organic beings originate from and consist of vesicles or cells, in my book upon Generation. (Die Zeugung. Frankfurt bey Wesche, 1805, 8vo.) These vesicles, when singly detached and regarded in their original process of production, are the infusorial mass, or the protoplasma (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 concerning the primo-constituent parts of the organic mass is now generally admitted or recognised, and I need not, therefore, add anything by way of apology for it or defence.

In mine and Kieser's Beyträgen zur vergleichenden Zoologie, Anatomie und Physiologie; Frankfurt bey Wesche, 1806, 4to, I