NATURAL HISTORY, in the widest sense, includes all natural science, and has the whole of creation for its subject. In this sense the term was employed by the philoso phers of antiquity. But it is now limited to those branches of science which relate to the crust of the earth and its productions. Of these, geology and mineralogy have for their subject inorganic portions of creation; botany and zoology, the various branches of which are often pursued as separate sciences, with physiology, have for their subject organized creatures. Natural history takes cognizance of the productions of nature. and of their relations to each other, with all the changes on the face of the earth, anti :ill the phenomena of life, both animal and vegetable. It derives assistance from other sciences, particularly chemistry and natural philosophy; and some of the branches of chemistry may also be regarded as branches of natural history. When man himself is considered as a subject of scientific study, psychology must be added to the branches of natural history, but in the term as commonly employed this can scarcely be said to be included.
In every department of natural history, classification is of the utmost importance, and scarcely less important is a scientific nomenclature suited to the classification. The subjects of study are so incalculably numerous that an arrangement of them in well defined groups is necessary to any considerable attainment in the knowledge of them; and it is only by systems of classification which arrange smaller groups in knowledge and these in larger and larger again, that natural history has been brought to its present state. The very division of natural history into different sciences is a result of such a chissitieittion, and implies it recognition of the largest and highest groups. It is nut. always in the establishment of these groups that the greatest difficulty is experienced. The primary distinction of all the subjects of natural history into organized and u»or gituized, or into those haying life and those not having life, presents itself very readily to every mind. Anti equrdly natural and necessary is the distinction of organized beings into plants and animals, however difficult it has been found to draw the precise limit between the lowest of plants and the lowest of animals. Another distinction readily presents itself to the student of living beings in the kinds which retain the snore characters front one generation to another. But here arises one of the most important of all the questions of natural history, what a species is and how it differs from a ra piety. For this we refer to the article SPECIES. But much difference of
opinion as there is on this point, the common and long-prevalent notion may be assumed, as suitable enough for guidance in all that relates to classification, that those are distinct si;erzes which cannot by any change of circumstances—or, let it be said, by any ordinary change of circumstances. and any whoderate period of tune—be so modified as be transmitted one into another, whilst- those are only rarietks of which the inodificatkin and transmutation can be thus effected. Thus, in botany, Bra ssica olerceea is a species, of which kale, cabbage, cauliflower, broccoli, Brussels sprouts, etc., are varieties. Species. grouped together, according to their natu ral affinities, form genera; but a genux does not necessarily consist of more .specibs than one; for, whilst some contain hundreds of species, others, apparently very distinct, con tain only one as yet known to naturalists. The distinctions by which genera are sepa rated are of course arbitrary, and are admitted to be so by those who deny that the distinctions between species are arbitrary, or that there is any uncerteinty about them but what arises from the imperfection of our knowledge; for, at present, it must be admitted on all bands, that the uncertainty is in iuninnerable instances VOIN great, what are species and what are varieties. The great object, however, in the formation of genera i- that they shall be accordant with the facts of nature; and so in regard to the larger or higher groups which are composed of associated genera, as tribes, families, orders, classes. etc. But in all this, the great difficulty is that affinities exist on many sides; and that groups cannot be satisfactorily arranged in the order of a series, but often rather as if they radiated from a common center; whilst otherwise viewed, the same groups might seem to radiate very differently front another common center. A natu ral xptrut is one framed with the utmost possible regard to all these facts; an rarti tid al fixes on one class of facts mid proceeds upon it, in disregard of all others. Sec BOTAN Y. In the inorganic departments of nature a species is of course something different from what it is in the organic. But classification still proceeds on the recog-. eition of facts in nature itself, which it is sought to exhibit in the groups that are formed. See MINERALOGY.
The nomenclature of natural history, in so far as it relates to organic beings, con tinues essentially as it was established by Linnaeus. See GENUS. The names have in ninny cases been changed, but not the mode of nomenclature.