1. It has a certain external and internal form, the latter being more usually called structure;
2. It occupies a certain position in space and in time;
3. It is the subject of the operation of certain forces in virtue of which it undergoes internal changes, modifies external objects, and is modified by them; and
4. Its form, place and powers are the effects of certain causes.
In correspondence with these four aspects of its subject, biology is logically divisible into four chief subdivisions—I. Morphology; II. Distribution; III. Physiology; IV. Aetiology.
Various accidental circumstances, however, have brought it about that the actual distribution of scientific work does not correspond with the logical subdivisions of biology. The difference in technical methods and the historical evolution of teaching posts (for in all civilized countries the progress of biological knowledge has been very closely associated with the existence of institutions for the diffusion of knowledge and for professional education) have been the chief contributory causes to this practical confusion. Details of the morphology of plants will be found in the articles relating to the chief groups of plants, those of animals in the corresponding articles on groups of animals, while the classification of animals adopted in this work will be found in the article [Zoology]. Distribution is treated of under [Zoological Distribution], [Plankton], [Palaeontology] and [Plants]: Distribution. [Physiology] and its allied articles deal with the subject generally and in relation to man, while the special physiology of plants is dealt with in a section of the article [Plants]. Aetiology is treated of under the heading [Evolution]. But practical necessity has given rise to the existence of many other divisions; see [Cytology], for the structure of cells; [Embryology], for the development of individual organisms; [Heredity] and [Reproduction], for the relations between parents and offspring.
(T. H. H.; P. C. M.)
BION, Greek bucolic poet, was born at Phlossa near Smyrna, and flourished about 100 B.C. The account formerly given of him, that he was the contemporary and imitator of Theocritus, the friend and tutor of Moschus, and lived about 280 B.C., is now generally regarded as incorrect. W. Stein (De Moschi et Bionis aetate, Tübingen, 1893) puts Bion, chiefly on metrical grounds, in the first half of the 1st century B.C. Nothing is known of him except that he lived in Sicily. The story that he died of poison, administered to him by some jealous rivals, who afterwards suffered the penalty of their crime, is probably only an invention of the author of the Ἐπιτάφιος Βίωνος (see [Moschus]). Although his poems are included in the general class of bucolic poetry, the remains show little of the vigour and truthfulness to nature characteristic of Theocritus. They breathe an exaggerated sentimentality, and show traces of the overstrained reflection frequently observable in later developments of pastoral poetry. The longest and best of them is the Lament for Adonis (Ἐπιτάφιος Ἀδώνιδος). It refers to the first day of the festival of Adonis (q.v.), on which the death of the favourite of Aphrodite was lamented, thus forming an introduction to the Adoniazusae of Theocritus, the subject of which is the second day, when the reunion of Adonis and Aphrodite was celebrated. Fragments of his other pieces are preserved in Stobaeus; the epithalamium of Achilles and Deidameia is not his.
Bion and Moschus have been edited separately by G. Hermann (1849) and C. Ziegler (Tübingen, 1869), the Epitaphios Adonidos by H.L. Ahrens (1854) and E. Hiller in Beiträge zur Textegeschichte der griechischen Bukoliker (1888). Bion’s poems are generally included in the editions of Theocritus. There are English translations by J. Banks (1853) in Bohn’s Classical Library, and by Andrew Long (1889), with Theocritus and Moschus; there is an edition of the text by U. Wilamowitz-Möllendorff in the Oxford Scriptorum Classicorum Bibliotheca (1905). On the date of Bion see F. Bücheler in Rheinisches Museum, xxx. (1875), pp. 33-41; also G. Knaack in Pauly-Wissowa’s Realencyclopädie, s.v.; and F. Susemihl, Geschichte der griechischen Litteratur in der Alexandrinerzeit, i. (1891), p. 233.