In correspondence with the long-established distinction between the plant and the animal, the two chief branches of biology, zoology and botany, have developed side by side, and are represented by two different chairs in the universities. Independently of these, there arose at the very beginning of scientific activity that field of inquiry which deals with human life in all its aspects—the anthropological disciplines and the so-called "mental sciences" (history, philology, psychology, etc.). Since the theory of descent has proved man's origin from vertebrate ancestors, and thus anthropology has been recognized as a part of zoology, we have begun to understand the inner historic connection between these various branches of anthropology, and to combine them in a comprehensive science of man. The immense extent and the great importance of this science have justified the creation of late years of special chairs of anthropology. It seems desirable to do the same for the science of the protists, or unicellular organisms. The cell theory, or cytology, as an elementary part of anatomy, has to be dealt with in both botany and zoology; but the lowest unicellular representatives of both kingdoms, the primitive plants (protophyta) and the primitive animals (protozoa), are so intimately connected, and throw so great a light, as independent rudimentary organisms, on the tissue cells in the histon, or multicellular organism, that we must regard as a sign of progress the recent proposal of Schaudinn to found a special institute and journal for the science of protists. One very important section of it is bacteriology.
The practical division of biology, according to the extent of the organic kingdom, leads us to mark out four chief provinces of research: protistology (the science of the unicellulars), botany (the science of plants), zoology (the science of animals), and anthropology (the science of man). In each of these four fields we may then distinguish morphology (the science of forms) and physiology (the science of functions) as the two chief divisions of scientific work. The special methods and means of observation differ entirely in the two sections. In morphology the work of description and comparison is the most important as regards both outer form and inner structure. In physiology the exact methods of physics and chemistry are especially demanded—the observation of vital activities and the attempt to discover the physical laws that govern them. As a correct knowledge of human anatomy and physiology is indispensable for scientific medicine, and the work requires a particularly large apparatus, these two sciences have long been studied separately, and have been handed over to the medical facility in the division of the academic curriculum.
The broad field of morphology may be divided into anatomy and biogeny; the one deals with the fully developed, and the other with the developing, organism. Anatomy, the study of the formed organism, studies both the external form and the inner structure. We may distinguish as its two branches the science of structures (tectology) and the science of fundamental forms (promorphology). Tectology investigates the features of the structure in the organic individual, and the composition of the body out of various parts (cells, tissues, and organs). Promorphology describes the real form of these individual parts and of the whole body, and endeavors to reduce them mathematically to certain fundamental forms (chapter viii.). Biogeny, or the science of the evolution of organisms, is also divided into two parts—the science of the individual (ontogeny) and of the stem or species (phylogeny); each follows its own peculiar methods and aims, but they are most intimately connected by the biogenetic law. Ontogeny deals with the development of the individual organism from the beginning of its existence to death; as embryology it observes the growth of the individual within the fœtal membranes; and as metamorphology (or the science of metamorphoses) it follows the subsequent changes in post-fœtal life (chapter xvi.). The task of phylogeny is to trace the evolution of the organic stem or species—that is to say, of the chief divisions in the animal and plant worlds, which we describe as classes, orders, etc.; in other words, it traces the genealogy of species. It relies on the facts of paleontology, and fills up the gaps in this by comparative anatomy and ontogeny.
The science of the vital phenomena, which we call physiology, is for the most part the physiology of work, or ergology; it investigates the functions of the living organism, and has to reduce them as closely as possible to physical and chemical laws. Vegetable ergology deals with what are called the vegetative functions, nutrition and reproduction; animal ergology studies the animal activities of movement and sensation. Psychology is directly connected with the latter. But the study of the relations of the organism to its environment, organic and inorganic, also belongs to physiology in the wider sense; we call this part of it perilogy, or the physiology of relations. To this belong chorology, or the science of distribution (also called biological geography, as it deals with geographical and topographical distribution), and œcology or bionomy (also recently called ethology), the science of the domestic side of organic life, of the life-needs of organisms and their relations to other organisms with which they live (biocenosis, symbiosis, parasitism).
Third Table
SYNOPSIS OF THE CHIEF BRANCHES OF BIOLOGY (1869)
Biology = The Science of Life
| I. | Protistology = the science of single cells—unicellular organisms. |
| The four chief branches of systematic biology. |
| II. | Botany = the science of plants—tissue plants (metaphyta). | ||
| III. | Zoology = the science of animals—tissue animals (metazoa). | ||
| IV. | Anthropology = the science of man—speaking primates. |
| A. Morphology = The Science of Forms. Anatomy and biogeny of organisms. | |
| A I. Anatomy. The science of structure. 1. Tectology. The science of structure. Cytology, science of cells. —— The science of fundamentalforms. Knowledge of the geometricalideal forms (mathematicallydefinable) in relationto the concrete real form ofthe individual. | A II. Biogeny. The science of development. 3. Phylogeny.Stem history. Paleontology and genealogy. 4. Ontogeny. 4a. Embryology. (Development within the fœtal membranes.) 4b. Metamorphology. (Modification of the organism after fœtal life.) |